Environmental analysisQuality control of water, soil, and air
02 Metrohm ... • is the global market leader in titration • is the only company to offer a complete range of ion analysis equipment – titration, voltammetry, and ion chromatography • is a Swiss company and manufactures exclusively in Switzerland • grants a 3-year instrument warranty and a 10-year warranty on chemical suppressors for ion chromatography • provides you with unparalleled application expertise • offers you more than 1300 applications free of charge • supports you with expert service through local representatives and regional support centers • is not listed on the stock exchange, but is owned by a foundation • gives the interest of customers and employees priority over maximizing profit
Metrohm – customized environmental analysis forwater, soil, and air samplesThe importance of environmental analysisThe rapid growth in the world population has led to sharp You can count on our know-how Metrohm offers you complete solutions for very specific 03increases in the consumption of energy and resources analytical issues. Your Metrohm contacts are profession-and in the production of consumer goods and che cals. mi als, who develop customized applications for you andIt is estimated that there are a total of 17 million chemi- pro vide you with professional support in all matters con-cal compounds on the market, including as many as cerning environmental analysis.100,000 that are produced on a large industrial scale. Discover on the following pages the solutions MetrohmThe effects of human activities on the environment are offers for analysis in the environmental compartmentscomplex and call for sensitive analytical methods and water, soil, and air.powerful analytical instruments.As a leading manufacturer of instruments for chemicalanaysis we know about these challenges. We offer you lstate-of-the-art instruments and systems, with which youcan monitor the composition of your water, soil, and airsamples.
Selected methods from the field of environmental analysis04 Substances introduced into the environment are distrib- uted among the environmental compartments water (hy I. Water As its physical state changes, water passes through all drosphere), soil (pedosphere), rock (lithosphere), and air spheres. It is the most frequently analyzed environmental (atmosphere), as well as among the organisms living on compartment and is also the easiest, because – unlike air them (biosphere). Only if we know the type and quantity or soil – it already exists in the liquid phase. If drinking of these contaminants can we protect the environment water samples are to be analyzed, sample preparation is and its inhabitants. This requires internationally accepted usually not necessary; however, it is usually unavoidable in standards, in which limits and test methods are defined. the case of wastewater samples. Metrohm instruments comply with numerous environ- mental standards. The following list contains a selec tion broken down according to environmental compartments. Parameter Standard Matrix Method Page Permanganate index ISO 8467 Drinking water Titration 6 DIN 38409-5 Surface water Titration ISO 6060 Drinking water, Chemical oxygen demand ISO 15705 Seawater, Titration 7 (COD) ASTM D 1252 Wastewater DIN 38409-44 Ca, Mg DIN 38406-3 Drinking water Titration 8 EPA 130.2 Sulfide ASTM D 4658 All types of water Titration Fluoride ASTM D 3868 Drinking water Titration 9 EPA 340.2 Wastewater Titration, Ion-selective Electrode (ISE) Free chlorine EPA 330.1 All types of water Titration DIN EN ISO 10304-1 All types of water Ion chromatography – – – Anions, e.g., F , Cl , Br , EPA 300.0, Part A Drinking and wastewater Ion chromatography 10 NO2–, NO3–, SO42–, etc. EPA 300.1, Part A Drinking water Ion chromatography EPA 9056 Drinking and wastewater Ion chromatography Chromium(VI), anions DIN EN ISO 10304-3 All types of water Ion chromatography Chromium(VI) ASTM D 5257 All types of water Ion chromatography EPA 218.7 Wastewater Ion chromatography ISO 11206 Drinking water Ion chromatography ASTM D 6581 Drinking water Ion chromatography DIN EN ISO 10304-4 All types of water Ion chromatography Oxyhalides DIN EN ISO 15061 Drinking and mineral water Ion chromatography 11 EPA 300.0, Part B Drinking and wastewater Ion chromatography EPA 300.1, Part B Drinking water Ion chromatography EPA 317.0 Drinking water Ion chromatography EPA 326.0 Drinking water Ion chromatography Cations, e.g., Li+, Na+, K+, NH4+, ISO 14911 Surface and drinking water Ion chromatography 2+ 2+ Mg , Ca , etc. ASTM D 6919 Wastewater Ion chromatography Amines (MMA, guanidine) – Wastewater Ion chromatography 12 Bromate EPA 321.8 Drinking water Ion chromatography (IC-ICP/MS) Bromate, halogenated acetic acids EPA 557 Drinking water Ion chromatography (IC-MS/MS) Perchlorate EPA 314.0 Drinking water Ion chromatography 13 EPA 332.0 Hg, As, Cr EPA 6800 Hydrosphere, Ion chromatography (IC-ICP/MS) Biosphere Zn, Cd, Pb, Cu, Tl, Ni, Co DIN 38406-16 Drinking and wastewater Voltammetry II III VI Cd, Pb, Cu, Fe /Fe , Cr – Seawater Voltammetry 15 CN– Sample preparation acc. rinking and wastewater D Voltammetry to DIN 38405-13 DIN 38406-17 Groundwater, raw water, U Voltammetry drinking water EDTA, NTA DIN 38413-5 Wastewater, sludge Voltammetry Anions, cations, All types of water VoltIC (Voltammetry and Various 16 heavy metals ion chromatography) pH value, conductivity, TitrIC (Titration and Various All types of water 17 anions, cations ion chromatography) Drinking water, pH value, conductivity, and parameters that can Process-dependent Boiler feed water, Online and atline be determined by titration specifications Cooling water, 19 process analysis Process water, or voltammetry Wastewater Further standard-compliant methods for water analysis can be found in the brochure water analysis (8.000.5027EN).
II. SoilThe soil is a multiphase system in which the hydrosphere, enter the human body through plants and animals.atmosphere, lithosphere, and biosphere exist side by side. The constituents of soil are very difficult to access andIt serves as a source of water and nutrients for plants, is difficult to mobilize. Sample preparation usually involvesa habitat for a large number of organisms, and is an im extraction and digestion procedures.portant carbon sink. Harmful soil pollutants can easily 05 Parameter Standard Matrix Method Page pH value ISO 10390 Soil pH measurement 22 Conductivity ISO 11265 Soil Conductivity measurement 23 Total organic carbon – Soil Titration 24 (TOC) Cyanide ISO 11262 Soil Continuous flow analysis 25 Anions, e.g., F–, Cl– – Soil Titration ISO 15192 DIN EN 15192 Chromium(VI) Soil Ion chromatography 26 EPA 3060A EPA 7199 Anions and cations – Soil Ion chromatography 27 ISO 11466 Trace elements Soil Voltammetry ISO 19730 28 Organophosporus pesticide AOAC 970.53 Soil Voltammetry residuesIII. AirThe atmosphere is an important thermal buffer against mo bility, enter our organism easily through breathing,space, and protects the earth from cosmic radiation. It is and influence the climate and weather. Filter methods,the place where clouds are formed and water is present and aerosol and gas collectors bring the constituents ofthere in all its physical states. Thus it is a heteo eneous r g air into the aqueous phase, which is preferable for chemixture of finely dispersed, solid or liquid paricles in a t mical analysis.gas (air). Its constituents are characterized by extreme Parameter Standard Matrix Method Page Saccharidic tracers – Particulate matter Ion chromatography, filter 31 ISO 16740 Chromium(VI) Workplace air Ion chromatography, filter 32 ASTM D 6832 Pb, Cd, Zn, Cu – Particulate matter Voltammetry, filter 33 Anions and cations – Particulate matter Ion chromatography, PILS* 35 Pb, Cd, Zn, Cu – Particulate matter Voltammetry, PILS* Anions and cations Ion chromatography and – Particulate matter 36 Pb, Cd, Zn, Cu voltammetry, PILS* Hydrogen chloride DIN EN 14791 Emissions, Chimneys Ion chromatography, MARGA* Sulfur dioxide DIN EN 14791 Emissions, Chimneys Ion chromatography, MARGA* 38 Nitrogen dioxide DIN EN 16339 Ambient air Ion chromatography, MARGA* * PILS is a semicontinuous aerosol sampler that is coupled to one or two analyzers (e.g., IC and/or VA); MARGA is the combination of aerosol and gas sampler including ion chromatographs.
I. Water06 Titration Sum parameters usually characterize similar chemical, Permanganate index according to DIN EN ISO 8467 physical, physicochemical or biological features of differ- The permanganate index determines the easily oxidizable ent components. Their advantage is in the fast determi- fraction of the organic constituents in water and is used, nation and informative value, which allow the sample to in a broader sense to evaluate the or nic chemical con- ga be evaluated quickly. Thus, for example, electrical con- tamination in waters with minimal or low contamination, ductivity provides valuable information on the salt con- such as drinking water samples. For determination, the tent of a water sample. Another important sum param- water sample is heated for ten minutes with sulfuric acid eter is the chemical oxidizability of water components, and an excess of permanganate solution of known con- which provides indications of the type and quantity of centration in a boiling water bath. After that, the per- organic material present in the sample. manganate consumption is determined by adding an excess of sodium oxalate solution and back-titrating the According to the oxidizing power of the oxidizing agents consumed oxalate with permanganate solution. The per used, a distinction is made between the permanganate m anganate index is expressed as the quantity of oxygen index and the chemical oxygen demand (COD). While the in mg/L that would be needed for oxidation. permanganate index is the more informative parameter for samples with minimal or low contamination, COD is suitable for severely contaminated samples. The MATi13 system for fully automatic determination of the permanganate index
07 The Mati12 system for fully automatic COD determinationChemical oxygen demand according to Automation solutions from MetrohmDIN 38409-44 and ASTM D 1252 Manual determination of the permanganate index andThe chemical oxygen demand (COD) is a measured value COD involves a great deal of work and, because the infor the sum of the substances in a certain volume of dividual manual steps are difficult to reproduce, usuallywater that can be oxidized by chromate. Chromate is a means inaccurate results.much stronger oxidizing agent than permanganate,which is why it also oxidizes most organic compounds Metrohm solves this problem with a fully au tomatedpractically completely into CO2. In sewage treatment system in which tiamoTM titration software controls allplants, COD is regarded as a valuable indicator for evalu- the individual steps − from sample preparation and theating treatment performance. addition of the various solutions right through to the recording and archiving of data. Identical sequencesFor volumetric determination of the COD, the sample of guarantee unique reproducibility. New applications canwater is heated over a defined period with potassium be added to the freely configurable systems at any time,dichromate. The remaining quantity of potassium dichro- no matter whether they are for the determination of themate is then back-titrated with ammonium iron(II) sul- pH value, conductivity, acid capacity, or for coupling withfate. an ion chromatograph. Thus, it is possible to adapt any standard system individually to the particular task in theThe water constituents are oxidized either in a special laboratory.COD heating device with reflux condensing or in a closedreaction vessel with an external heat source. Titrationtakes place directly in the reaction vessels without theneed to transfer the content to other vessels. This pre-vents any sample losses and saves valuable time, especially when there is a high sample throughput.
08 Calcium and magnesium according to DIN 38406-3 and EPA 130.2 With regard to the determination of water hardness, a distinction is made between temporary hardness (carbo nate hardness) and permanent hardness (sulfate hard- ness). Another important parameter includes the total hardness that represents the sum of the dissolved alcaline earth metals, but that is approximated as the sum of the calcium and magnesium hardness. Temporary hardness is determined by end point titration with hydrochloric acid, total hardness by complexometric titration with Na2EDTA as titrant and a Ca2+-selective electrode. Combined polymer membrane electrode for calcium determination Chloride Chloride ions are determined by potentiometric titration with AgNO3 as titrant and a combined Ag-ring electrode, the Ag Titrode, following prior pH adjustment with nitric acid. The maintenance-free Ag-Titrode uses a pH glass membrane as reference electrode, which means that no refilling of electrolyte is required. The Ag-Titrode for chloride determination
09Fluoride (ASTM D 3868) and Automation – greater efficiency and reproducibilitysulfide (ASTM D 4658) With Metrohm’s titrators and automation solutions, it isSulfide and fluoride ions are determined by ion-selective possible, upon request, to offer any fully automated titra-electrodes. tion system, no matter whether the requirement is for de termination of a single parameter or several parame-For fluoride determination, a buffer substance is added ters in one sample run (e.g., pH value, conductivity,to the sample. This buffer substance both maintains the alkalinity, and total hardness). But that is not all: theionic strength, regulates the pH value and complexes in tiamoTM titration software also allows numerous third-terfering aluminum and iron(III) ions. party devices to be incorporated − for example, for determining turbidity according to DIN EN ISO 7027 orTo measure sulfide, a buffer is added. This both regulates for determining color according to DIN EN ISO 7887.the pH value and prevents the oxidation of sulfide byatmospheric oxygen.
Ion chromatography10 Modern ion chromatography (IC) allows efficient separa- tion and determination of inorganic and low-molecular to be monitored on account of their suspected carin genic properties. c o organic anions and cations. Various separation mecha- nisms and types of detection as well as the possibility of Before injection, the samples pass through the ultrafiltra- automated sample preparation make IC a proven routine tion cell mounted directly on the 858 Professional IC method in water and environmental analysis. Sample Pro essor. Sample preparation and analysis are fully c automatic. The equipment is controlled, the data collected Oxyhalides and standard anions in drinking and managed, and the system monitored by the intelligent water (EPA 300.1) MagIC NetTM chromatography software. The clear symbols, Chlorate, chlorite, and bromate are by-products that are well laid-out presentation, and intuitive operation make formed by oxidation of the halides when drinking water analysis remarkably easy. and mineral water are disinfected. Their concentration needs chloride; 11 mg/L nitrate; 12 mg/L sulfate; 8 mg/L 2.4 2.2 Conductivity [µS/cm] 2.0 1.8 dichloroacetate; 500 µg/L fluoride; 95 µg/L 1.6 phosphate 100 µg/L bromate; 11 µg/L bromide; 47 µg/L chlorate; 18 µg/L chlorite; 10 µg/L nitrite; 40 µg/L 1.4 1.2 1.0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Time [min] Drinking water sample, spiked with 10 µg/L of each ClO2–, BrO3–, ClO3–, 40 µg/L of each NO2–, Br–, 100 µg/L PO43–, 500 µg/L dichloroacetate; column: Metrosep A Supp 7 - 250/4.0 (6.1006.630); eluent: 3.6 mmol/L Na2CO3, 0.8 mL/min; column temperature: 45 °C; sample volume: 20 µL
Bromate in drinking water (EPA 326.0)Bromate forms during the ozonization of drinkng water. i de termination of bromate in the lower µg/L range. In the 11Several international standards stipulate detection limits ng/L range bromate can be detected by means of IC/MSand test methods. Depending on the required detection coupling or post-column derivatization with potassiumlimit, different detection methods can be used. Conduc iodide and subsequent UV detection.ti detection with chemical suppression allows the vity tap water sample spiked with 1 µg/L bromate 3.0 unspiked tap water sample 2.5 bromate 2.0 Intensity [mAU] 1.5 1.0 0.5 0.0 -0.5 0 1 2 3 4 5 6 7 Time [min] Spiked and unspiked drinking water sample; column: Metrosep A Supp 16 - 100/4.0 (6.1031.410); eluent: 100 mmol/L H2SO4, 19.3 µmol/L ammonium molybdate tetrahydrate, 0.8 mL/min; post-column reagent: 0.27 mol/L KI, 0.2 mL/min; column temperature: 45 °C, wavelength: 352 nm; sample volume: 1000 µLBromate determination: overview of test methods and detection limits (acc. to DIN 32645) EPA method Injection volume Detection limit Ultrapure water rinking water* D [μL] [μg/L] Conductivity detection with 300.1 100 0.130 0.390 chemical suppression IC/MS coupling; MS detection 100 0.006 0.007 Post-column derivatization with 317.0 100 0.210 0.640 o-dianisidine; VIS detection Post-column derivatization with KI; 326.0 1000 0.032 0.066 UV detection *Drinking water matrix: 100 mg/L of each chloride, sulfate, and carbonate
12 Aliphatic amines in wastewater Aliphatic amines are important starting materials and in Short-chain aliphatic amines in industrial wastewaters termediate products in the chemical and pharmaceutical can be determined easily on a cation-exchange column industries. They are used to produce solvents, crop pro- with subsequent conductivity detection. Not only impor- tection agents, polymers, detergents, dyes, explosives, tant amines (methylamine, dimethylamine, trimethylamine, lubricants, and pharmaceuticals. Their use on a large in ethanolamines, guanidine, etc.), but also alkali metals dustrial scale has led to significant discharges into aqua and alkaline earth metals can be detected in a single de tic systems. Secondary amines, especially, are re ded as gar termination. There is no need for complicated derivai t hazardous to waters, as they react even at trace concen- zation procedures, such as those in gas chromatography. trations with nitrite to form carcinogenic nitrosamines. Interfering particles, colloids, algae, or bacteria pre sent in many (waste)water samples are removed fully automati- cally by inline ultrafiltration before analysis. -560 sodium; 20 mg/L -565 ammonium; 10 mg/L Conductivity [µS/cm] methylamine; 10 mg/L -570 aminoguanidine; 5 mg/L -575 guanidine; 5 mg/L -580 -585 -590 0 1 2 3 4 5 6 7 8 9 10 11 12 Time [min] Water sample spiked with wastewater-typical amines; column: Metrosep C 4 - 100/4.0 (6.1050.410); eluent: 1.7 mmol/L HNO3, 0.7 mmol/L dipicolinic acid, 5% acetone, 0.9 mL/min; sample volume: 10 μL
Modern detection methods in ICCoupling IC with mass spectrometry (MS) and inductively made between the different oxidation states of one andcoupled plasma mass spectrometry (ICP/MS) brings the same element. This element species analysis is impor-detection limits down to ultratrace levels. Whereas the tant for elements such as arsenic, chromium, mercury,great advantage of structure-specific IC/MS is that it is selenium, and gadolinium, which occur as simple ele-possible to identify compounds not only by way of their mental and molecular ions or as polar and ionic coordi- 13retention time but also on the basis of their MS spectrum nation compounds, and display different toxicities,(organic acids), IC-ICP/MS enables a distinction to be depending on their bonding. Separation and detection of arsenite, monomethylarsenate, dimethylarsenate and arsenate by IC-ICP/MS; column: Metrosep A Supp 15 - 150/4.0 (6.1030.420); eluent: 8 mmol/L ammonium nitrate, pH = 8.3, 0.7 mL/min; sample volume: 10 µL; ICP/MS: without reaction and collision mode, m/z: 75Further applicationsAnalyte Coupling EPA method Remark IC/MS – along with other oxyhalidesBromate IC-MS/MS EPA 557 along with haloacetic acids and dalapon IC-ICP/MS EPA 321.8 after removal of haloacetic acids EPA 332.0Perchlorate IC/MS in water and soil samples EPA 6860Anions and IC/MS – parallel determination in various matricesorganic acidsAmines IC/MS – very sensitive determination in water samplesOrganic acids• Acetate IC/MS – occur in process water along with a high salt matrix• Propionate• ButyrateChromium(VI) IC-ICP/MS EPA 6800 speciation analysisArsenic IC-ICP/MS – speciation analysisSelenium IC-ICP/MS EPA 6800 speciation analysisMercury IC-ICP/MS EPA 6800 isotope dilution mass spectrometryGadolinium- analysis of gadolinium chelates (Gadovist, Magnevist, etc.)containing MRI IC-ICP/MS – and free gadolinium ionscontrast agents
Voltammetry14 Voltammetric trace and ultratrace analysis of drinking water, groundwater, surface water, seawater and waste exation capacity; it indicates the amount of heavy metal ions which is barely complexed. Determination is achieved w ater is used to determine electrochemically active inor- by voltammetric titration. After each addition of me tal ganic ions. It is frequently employed to complement and tit ant, a voltammogram is registered. Plotting the currents r validate spectroscopic methods. Its features are: compact of the respective peak heights versus the metal concen- equipment, relatively low investment and running costs, tration provides a titration curve from which the com- simple sample preparation, short analysis times, and high plexation capacity is deduced. accuracy and sensitivity. Versatile application areas Speciation analysis Voltammetry is especially suitable for laboratories in which Another advantage of voltammetry is the possibility to only a few parameters have to be monitored with a mod- distinguish bet ween different oxidation states of metal erate sample throughput. Important fields of application ions (speciation) as well as between free and bound include environmental monitoring, limnology, hy - dro metal ions. This provides important information regard- gra hy, oceanography, marine biology, and soil science. p ing the bioavailability and toxicity of heavy metals. 797 VA Computrace Determination of the complexation capacity The 797 VA Computrace is a modern, user-friendly all- Natural waters often contain dissolved organic com- round measuring stand that enables accurate and sensi- pounds that complex heavy metals and thus change bio tive determination of metal and nonmetal traces with the availability and toxicity of the latter. The parameter used help of voltammetric and polarographic methods. to quantify the organic ligands in a sample is the compl- Detection limits Element Detection limit [ng/L] Antimony SbIII/SbV 200 Arsenic AsIII/AsV 100 Bismuth Bi 500 Cadmium Cd 50 Chromium CrIII/CrVI 25 Cobalt Co 50 Copper Cu 50 II III Iron Fe /Fe 50 Lead Pb 50 Mercury Hg 100 Molybdenum MoIV/MoVI 50 Nickel Ni 50 Platinum Pt 0.1 Rhodium Rh 0.1 Selenium SeIV/SeVI 300 Thallium Tl 50 Tungsten W 200 Uranium U 25 Zinc Zn 50
15Many toxic transition metals and a few anions can be Cyanidedetermined voltammetrically, with a high degree of sen- Apart from heavy metals, voltammetry can also be usedsitivity and without prior sample preparation, in drinking for trace analysis of a few anions. For example, free cya-water and groundwater. Here are a few relevant examples: nide in a concentration range of 0.01...10 mg/L can be determined easily and reliably even in sulfide-containingNickel and cobalt solutions with a large excess of phosphate, nitrate, sul-These metal ions must be determined regularly in water fate, and chloride.samples. DIN 38406 Part 16 describes the determinationof these ions in different types of water. -150 Ni -125 -100 I [nA] -70 -50 Co -25 0 -0.80 -0.90 -1.00 -1.10 -1.20 -1.30 U [V] Voltammetric determination of nickel and cobalt in sea water according to DIN 38406-16
16 The fully automatic VoltIC pro consists of several 800 Dosinos, a 797 VA Computrace, an 858 Professional Sample Processor, and an 850 Professional IC AnCat (from right to left). VoltIC pro – Voltammetry and ion chromatography VoltIC pro combines voltammetry (VA) and ion chroma- tography (IC) in a single system and permits the fully automatic analysis of anions, cations, and heavy metals. The necessary sample preparation steps are performed by sharing the same liquid handling system and sample changer, which directs the samples to the VA analyzer and the ion chromatographs. VoltIC pro can be con- trolled with just one software. All the results are filed in a single database and can be converted into an easily readable report by pressing a button. VoltIC pro is very flexible and can be easily adapted to a wide variety of requirements in the analytical laboratory. Available Metrohm instruments (IC and VA) can be easily extended to a «VoltIC pro» system. The VoltIC Report: All the results at a glance
TitrIC pro – Titration and ion chromatographyTitrIC pro stands for a unique combination of direct measurement, titration, and ion chromatography and permits TitrIC pro comes in three versions – the basic, ad ced van and high end systems. All three systems determine tem- 17the fully automatic determination of temperature, con- perature and conductivity, pH as well as p and m value,ductivity, pH as well as p and m value, alkalinity, total and analyse anions by ion chromatography.hardness and numerous ion concentrations. Just as in theVoltIC pro system, the analysers use the same liquid han- In the basic system, TitrIC pro I, the content of Ca anddling instruments, a common sample changer, and the Mg is measured by titrimetry. In TitrIC pro II and TitrIC prosame database. The system is controlled by the master III, cations are determined by ion chromatography. Insoftware MagIC NetTM, while the titration software addition, TitrIC pro III has a sample changer with thetiamoTM runs in the background. TitrIC pro has impres- DisCover function for the automatic removal of the lid ofsively short analysis times, uses little space and gives high the sample vessel. If required, additional determinationsprecision results. can be integrated into the «TitrIC pro» systems.The High-End-System TitrIC pro III consists of 856 Conductivity Module, two 800 Dosinos, an 802 Magnetic Stirrer, a 905 Titrando,and 815 Robotic USB Sample Processor XL and the 850 Professional IC for anions and cations.
Potentiostats and galvanostats18 Energy from wastewater: the microbial fuel cell Like all living beings, microorganisms meet their energy Initial results show that the degradation of pollutants in requirements by breaking down energy-rich substances. wastewater can be used to recover energy. The target is Humans make use of this in sewage treatment plants, energy-neutral wastewater purification. For this, how- where bacteria mineralize the organic pollutant load to a ever, the electron transfer processes still need to be opti- large extent. The microorganisms release electrons, which mized, e.g., by increasing the size of the electrode surface. they transfer to electron acceptors such as oxygen, At present, work is being done with electrodes made nitrate, and sulfate. If this transfer of electrons is from a up of countless conducting carbon fibers on which the mediator – i.e., an electron bridge – to a solid elec tron bacteria sit. The electrochemical impedance spectroscopy receptor such as an anode, an electric current will flow, ca pabilities of the Autolab PGSTAT128N with FRA32M provided there is also a cathode and a power consumer. module allow the electron transfer kinetics and interfacial This way, bacterial energy is directly converted to electri- properties to be monitored. cal energy. It is essential that the bacteria are in di rect contact with the electrode in the form of a biofilm. www.metrohm-autolab.com
Online and atline analysis systems fromMetrohm ApplikonOnline and atline Process Analyzers from MetrohmApplikon are the preferred solution for process monitoring ence, we offer a wide range of analyzer products and integrated systems for diverse applications and industries 19in a wide range of industries. Using the complete range to meet the challenging requirements and demands ofof modern ion analysis (pH value, conductivity, and redox your process.potential titration, KF titration, photometry, ISE measure-ments, and voltammetry) Metrohm Applikon Pro cess Metrohm Applikon is part of the Metrohm Group andAnayzers pro l vide high precision results for any wet-che represented in over 35 countries. Our regional and localmical parame ers you need right at your production line. t presence offers knowledgeable support in sales, applica- tions, project engineering and start-up. We intend to beMetrohm Applikon has specialized in online and atline cess monitoring partner for years to come. your proprocess analysis for over 35 years. With this vast experi-Offline lab analysis• Manual sampling• Sample transport to the lab• Sample registration and analysis in the labAtline analysis• Manual sampling• Continuous manpower needed• Automated lab analysis close to sampling point inside plant• Ideal where mutiple samples have to be taken at several sampling points along the processOnline analysis• In-process measurement & response• Automated sampling & registration• Automated sample preconditioning• Automated lab analysis• Fast feedback of results• Very limited manpower needed• Close loop control
Process analysis20 Customized online and atline process control Because of the outstanding dissolving properties of wa Alert range of analyzers The Alert analyzers are either based on colorimetric or ter a large number of organic and inorganic compounds ion-selective electrode (ISE) methods. The ISE methods accumulate in it. This requires powerful analysis that mo are generally used for measurements in the ppm and ni tors the composition of the water continuously. With percent range, whereas the colorimetric techniques are the process analyzers from Metrohm Applikon this is used for the ppb to ppm range. Some typical applications possible 24 hours a day, 7 days a week. The analyzers are for the Alert analyzers are: used directly on-site, as close as possible to the process, and run without any operator intervention. More ver, it o Sodium and silica in power plants makes no difference whether a single parameter is to be Both sodium and silica play a major role in corrosion determined in a single sample stream or several different processes that occur in cooling water systems. For power parameters are to be determined simultaneously in com- plants, it is essential to monitor the concentrations of plex, multiple sample streams – whatever your require- these species. With the Alert Ion Analyzer equipped with ment, Metrohm Applikon can offer you an appropriate the Metrohm Na+ ISE, it is possible to measure sodium online or atline analyzer. concentrations down to 1 ppb. If lower detection limits are required, the Alert analyzer can be replaced by the Proven wet-chemistry methods more accurate ADI 2018 analyzer. Silica in cooling water All analyzers are based on wet-chemical analysis tech- or high-purity water can be determined with the Alert niques such as titration, colorimetry, or ion-selective elec Colorimeter at concentrations as low as 1 ppb. tr ode measurements. Most of the well-established labo- ratory methods for water analysis can be easily trans- ferred to the analyzers. In online analysis, sampling and sample preparation are at least as important as the ana- lyzer itself. Metrohm Applikon has a lot of expertise in this area and configures custom-made sampling systems, for example, for filtration, sample taking from pressur ized containers or degassing. Straightforward network integration The analyzers are all equipped with possibilities for digital as well as analog outputs. Results, for example, can be transferred via 4...20 mA outputs, where alarms can be as transmitted via the digital outputs. Digital inputs, in turn, can be used for remote start-stop purposes. www.metrohm-applikon.com ADI 2045TI – the flexible analyzer for online applications
21Chemical oxygen demandThe chemical oxygen demand (COD) is one of the most other ana lyses. In addition, Metrohm Applikon offers aimportant sum parameters for assessing wastewater pol- large num er of sample preparation systems that can be blution. Metrohm Applikon offers both titrimetric determi- combined with any application, no matter how unusualnation, described already on page 7, and also colorimet- that application might be.ric determination: depending on the required detectionlimit, continuous COD determination can be performed Iron in drinking waterby either the ADI 2045TI or the ADI 2019 online analyzer. The taste of drinking water depends to a large extent on its origin and treatment. Water contains differentHeavy metals, phosphates, nitrates, and COD in amounts of magnesium, iron, sulfate, and carbonate,wastewater depending on whether it has passed through stone, clayNumerous parameters need to be continuously moni- or gravel sand. Low concentrations of iron below 2 mg/L,tored in industrial and municipal wastewaters. These especially, have a significant effect on taste. Many waterinclude, for example, the heavy metals cadmium, lead, suppliers use sand filters to remove the iron. ALERT ana-zinc, and cobalt, and also the anions nitrate, ammonium, lyzers, developed specifically for water analysis, ensurephosphate, and sulfate. Metrohm Applikon has a wide continuous monitoring of the filter performance. Ironrange of analyzers available: while the ADI 2045VA is can be detected colorimetrically in the presence of adesigned specifically for determining heavy metals, the color indicator – and this can be done every six minutes.ALERT analyzers ADI 201Y and ADI 2045TI perform the
II. Soil22 Determination of pH value and conductivity The pedosphere is the name given to a highly complex A simple method for determining the pH value is de cri s boundary area where the lithosphere, hydrosphere, at bed in ISO 10390. It describes the slurrying of an airdried mosphere and biosphere coexist. As a multiphase system, and sieved (max. 2 mm sieve) soil sample with distilled the pedosphere consists predominantly of soil mineral water and subsequent measurement. Alter aiely, ex n tv matter, approximately equal proportions of soil air and traction can be performed using 0.01 molar CaCl2 or soil water, and a small amount of organic matter. The 1 molar KCl. The cations in these solutions displace the pedosphere forms the key basis of life for plants, animals, protons that are absorbed on the ion exchangers of the and humans. Harmful substances contained in it come soil as quantitatively as possible. mainly from weathering, cultivation, or the air. Soil pH value – soil reaction according to ISO 10390 The pH value of a soil sample is the most frequently de termined parameter in soil analysis. It is the characteristic value of what is known as «soil reaction» and allows soils to be classified according to their acidity and alkalinity. Determination of the pH value provides information about the acid or base action of the soil solution. This in turn is enormously important for the nutrient supply and microbial activity of the soil. For example, many metals (trace elements) are considerably more mobile in acidic soils. If the soil pH values are very low, toxic levels can soon be reached and these can damage the roots of plants. On the other hand, excessively high pH values quickly lead to a shortage of trace elements because of immobilization. The flat membrane electrode is ideal for pH measurements in sediment-containing sample solutions. The 827 ph lab for the laboratory
23Determination of electrical conductivity in soilsamples according to ISO 11265The determination of conductivity provides qualitativein formation about the amount of dissolved salts in thesoil. It allows conclusions about the ability of the soilwater to mobilize mineral substances in the soil.To determine electrical conductivity, a weighed-out quantity of a dried soil sample is shaken up with a de finedvolume of distilled water and then measured directly.
Titration24 Total organic carbon (TOC value) Dead soil organic matter is known collectively as humus. Humus does not form a homogeneous soil fraction, but exists in a variety of forms, depending on the degree of decomposition. It provides plants with nutrients and forms an important habitat for many soil-dwelling organ- isms. The most important component of humus is the total organic carbon (TOC), which is also used generally as a measure of the humus content. The determination of the TOC value of a soil sample is based on the Walkley-Black method. For this, an air-dried soil sample is treated (after determination of the water content) with a potassium dichromate solution to which sulfuric acid has been added. As a result, all the organic carbon constituents in the soil sample are oxidized. The unconsumed dichromate is then back-titrated with an iron sulfate solution. Stand-alone Titrator 916 Ti-Touch for routine analysis
25Important soil parameters – overviewMethod Sample preparation Detection type TitrantpH value (ISO 10390) Slurrying Direct measurement –pH value for the determina- Continuous pH control to Direct measurementtion of the leaching behaviour determine the influence (with continuous eluate –of inorganic components from of pH value on leaching analysis)waste bevaviour Conductivity (ISO 11265) Slurrying Direct measurement –Total organic carbon Visually with barium(TOC), Walkley-Black K2Cr2O7/H2SO4 digestion 1 mol/L FeSO4 (acidic) diphenylamine sulfonatemethodAluminium Extraction Visually, phenolphthalein 0.02 mol/L NaOH Carbonate content, Soil sample is shaken with a) Photometrically withPiper method 0.2 mol/L HCl and allowed phenolphthalein(also known as rapid titration to settle; 10 mL of the 0.1 mol/L NaOH b) phenolphthalein,or acid neutralization supernatant solution is SET titration to pH 7.8method) back-titrated with NaOH a) Photometrically withAcidity Ion exchange with phenolphthalein 0.025 mol/L NaOH«Exchangeable acidity» (H + Al) 1 mol/L KCl b) Potentiometrically, SET titration to pH 7.6Total cyanide and easily a) Photometrically withreleased cyanide Distillation phenolphthalein 0.005 mol/L AgNO3(ISO 11262) b) PotentiometricallySoluble anions Extraction with CO2-free SET titration tocarbonate/bicarbonate 0.1 mol/L HCl dist. Water pH 8.4 and 4.4(alkalinity)
Ion chromatography26 Chromate(VI) in soil samples Chromium occurs primarily in the stable oxidation states Ion chromatography can detect chromate in the soil Cr(III) and Cr(VI). The oxidation state determines the bio- down to μg/L levels. Here, the relatively large, doubly logical and toxicological properties, which could hardly charged chromate anion is separated from the other be any more different: Cr(III) is one of the essential trace anions on an anion-exchange column and then convert- elements and plays an important role especially in the ed by post-column reaction with 1,5-diphenylcarbazide metabolism of fats and glucose, whereas hexavalent solution to form a reddish-violet complex that is analyzed chromium is very toxic and carcinogenic. at 540 nm with a UV/VIS detector. Chromium is present in different concentrations in all The sample preparation of soil samples is a demanding types of soil and rock. It usually occurs in the cationic and task. It is essential to ensure that the extraction solution less bioavailable trivalent form; it can, however, also oc releases the chromate from the samples without there cur as toxic and very mobile chromium(VI) anion – usu- being any change in the oxidation state of the chromate. ally as a result of anthropogenic input. Because of the For most soil samples, alkaline digestion according to EPA differences in toxicity, the total concentration of chromi- 3060A or ISO EN 15192 is recommended. Before ion um is of less interest than the concentration of chromate. chromatographic determination, filtering with 0.45 μm filters is required. This can also be automated conveni- ently with the use of an inline ultrafiltration cell. 12 10 Intensity [mAU] 8 Chromium(VI); 6.9 mg/kg 6 4 2 0 1 2 3 4 5 6 7 8 9 10 11 12 13 Time [min] Worked-up soil sample (2.5 g soil in 100 mL 0.25 mol/L NaOH/0.14 mol/L Na2CO3, then dilute with ultrapure water 1:10); column: Metrosep A Supp 5 - 250/4.0 (6.1006.530); eluent: 15 mmol/L Na2CO3, 10 mmol/L NaOH, 0.7 mL/min; sample volume: 100 μL; post-column derivatization with 0.5 g/L 1,5- diphenylcarbazide/10% methanol/0.5 mol/L H2SO4, flow rate PCR: 0.5 mL/min; UV/VIS detection at 540 nm
27Anions and cations in soil samplesThe nutrient content in soil samples determines plant Ion chromatography with conductivity detection enablesgrowth and is of great importance especially with regard rapid determination of the nitrogen components nitrate,to agricultural use. Of prime interest here are the concen- nitrite, and ammonium, and also of the ions sulfate,trations of the main nutrient elements (macronutrient phosphate, calcium, magnesium, and potassium. Sampleelements) nitrogen, phosphorus, potassium, calcium, mag preparation includes aqueous extraction of the soil samples.n esium, and sulfur. chloride; 262.9 mg/kg 3.8 3.4 nitrate; 406.4 mg/kg 3.0 Conductivity [µS/cm] 2.6 2.2 sulfate; 183.6 mg/kg phosphate; 104.2 mg/kg 1.8 nitrite; 30.2 mg/kg 1.4 1.0 0.6 0.2 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Time [min] Anion determination in a worked-up soil sample, 10 g seed compost in 100 g water, then extract for 10 minutes in the ultrasonic bath, dilute with ultrapure water 1:10 (v/v) and then filter with 0.45 μm filters and RP cartridges; column: Metrosep A Supp 5 - 250/4.0 (6.1006.530); eluent: 3.2 mmol/L Na2CO3,1.0 mmol/L NaHCO3, 5% acetone, 0.7 mL/min; column temperature: 30 °C; sample volume: 20 μL
Voltammetry28 Trace elements and harmful pollutants in the soil The determination of the nutrient content in the soil tion methods are described in standards (e.g., ISO 12914). requires not only ion chromatographic analysis of the The extracts obtained can usually be determined directly main nutrient elements, but also determination of the by voltammetry. essential trace elements iron, manganese, zinc, and cop- per. This can be achieved very accurately and sensitively Another application of voltammetry is the determination by voltammetry. Moreover, voltammetry is suitable for of organophosphorus pesticide residues, such as, for analyzing harmful heavy metals such as lead, cadmium, example, diazinon, malathion, parathion-methyl, and pa chromium, mercury, uranium, and zinc in the soil. rahion, according to AOAC 970.53. Through extraction t with organic solvents the electrochemically active sub- In contrast to water analyses, ion analysis in soils is usu- stances are separated from the soil matrix and then ally preceded by extraction or digestion to transfer the enriched by adsorption on the HMDE and determined by ions into the aqueous solution. Various sample prepara- reduction.
Potentiostats and galvanostatsAnalysis for the electroremediation ofcontaminated soils 29Soils contaminated with heavy metals and organic com- substances, such as phenols, aromatic amines, or halogepounds represent a serious risk to the environment, which nated hydrocarbons, are oxidized on the anode. Elecro tis why cost-effective and environmentally compatible re remediation is ideal for fine-grained clay, loam, or siltmediation of contaminated sites is becoming increasn ly i g soils with a high water-retention capacity, where other inurgent. In situ methods where contaminated soils are situ remediation techniques usually fail.treated without being excavated are the state of the art.A very promising method is electroremediation (also The first Autolab potentiostats/galvanostats were devel-known as electrochemical remediation), where se of ries oped exactly two decades ago for this type of applica-anodes and cathodes installed in the soil body and con- tion. By combining a PGSTAT128N potentiostat/galva-nected to a direct-current source induce an electrical nostat (cyclic voltammetry and galvanostatic analysis)field, under the influence of which electrokinetic trans- and a booster it is possible to track the redox reactionsport and redox processes take place. As a result, heavy – the oxidation of organic compounds and the reductionmetals are reduced on the cathode and harmful organic of heavy metals – taking place in the soil body.Autolab PGSTAT128N with BSTR10A 10A Current Booster www.metrohm-autolab.com
30 III. Air On average about 300,000 m3 air pass through a per- production). By reflecting sunlight and acting as conden- son’s respiratory system in the course of a lifetime. In this sation seeds for cloud formation, they influence our cli- way, impurities in the atmosphere directly enter the mate and weather. lungs. Especially dangerous are the aerosols that contain particles with diameters of less than 10 µm – also know The chemical composition of aerosols is highly complex as particulate matter. These are airborne heterogeneous and not yet fully understood. To estimate the effects of mixtures of substances made up of minute particles, aerosols on health and climate, it is essential to know some of which are solid and some liquid. The smaller their chemical composition. Sampling is done using two these particles are, the deeper they go into the lungs. different types of aerosol collector. The first type are filter Once they reach the place where the gas exchange collectors that are based on the deposition of suspended occurs, the pulmonary alveoli, there is just one micron of particles on surfaces; they usually require a pump, are tissue between them and the blood stream. operated in offline mode, and supply data over prolon ged accumulated periods. The second type are powerful Aerosols come both from natural sources (volcanic erup- aerosol collectors such as PILS or MARGA that work pri- tions, sea spray, desert dust, fire, biogenic input) and from marily in online mode and provide semicontinuous data. anthropogenic sources (burning of fossil fuels, industrial
Filter methodsThe particulate matter contained in the air is collected onfilters with a certain air flow over a defined period of time. Thus, concentration profiles of these saccharidic tracers make it possible to obtain indications of sources of aero- 31Sampling is usually in accordance with DIN EN 12341. sols. For example, analysis of the saccharide compositionThe composite air samples of particulate matter are ex- in summer filters shows a significantly higher proportiontracted and the extract is then analyzed using ion chro- of sugar alcohols. In winter filters, by contrast, there is amatography (IC) or voltammetry (VA). predominance of anhydrosugars, especially levoglucosan.Saccharidic tracers in particulate matter by IC Following direct water extraction by the aerosol filters,The anhydrosugars levoglucosan, mannosan, and galac- the saccharidic tracers are separated by ion chromatog-tosan are produced when cellulose and hemicellulose are raphy and determined reliably down to lower ng/m3 lev-burnt and act as tracers for the combustion of biomass. els by way of pulsed amperometric detection (PAD). TheBy contrast, the sugar alcohols arabitol and mannitol are IC-PAD method requires no derivatization, can be auto-tracer substances for biological processes: when fungi mated easily and is suitable for routine use with largefling spores into the air, the concentration of mannitol in sample series.the aerosol increases. Studies in the Amazon rain forestshowed that the biogenic fraction consisted of fungalspores and formed up to 50% of the ambient aerosol.Determination of saccharidic tracers in filter extracts from a) a winter filter and b) a summer filter; ultrasound-assisted extraction withultrapure water; columns: Metrosep A Supp 15 - 150/4.0 (6.1030.420) coupled to Metrosep Carb 1 - 150/4.0 (6.1013.010); eluent:70 mmol/L sodium hydroxide, 0.65 mL/min; column temperature: 32 °C; sample volume: 100 µL; PAD measuring mode (gold work-ing electrode), measuring time 100 ms
32 Chromium(VI) in the particulate matter of indoor air – IC method according to ASTM D 6832 When breathed in, water-soluble chromium(VI) particles The method described in ASTM D 6832 for chromium(VI) in the PM2.5 fraction pass all the way through to the determination in the particulate matter of indoor spaces pulmonary alveoli. There they penetrate the extremely describes an ion chromatographic separation of the thin tissue and enter the liver and kidney cells by way of chro mium(VI) species with post-column derivatization the blood plasma. Starting out from the red cells, Cr(VI) and spectrophotometric detection. The sampling and thus interacts with the cellular protein molecules of the sample preparation techniques chosen are such that no DNA. transformation occurs between trivalent and hexavalent chromium compounds. Furthermore, a distinction can be Like other carcinogenic compounds, chromium(VI) is made between soluble and insoluble chromium(VI) com- subject not to an occupational exposure limit, but to the pounds by choosing the appropriate extracting agent. ALARA principle of minimization (as low as reasonably achievable). It requires the emissions of carcinogenic substances to be reduced to the minimum. This calls not only for speciation analysis, but also for detection limits in the low μg/L range. 26 24 22 20 chromium(VI); 390 µg/L 18 Intensity [mAU] 16 14 12 10 8 6 4 2 0 0 1 2 3 4 5 6 7 8 9 10 11 12 Time [min] Determination of the insoluble chromium(VI) content in filter extracts of an air sample; ultrasound-assisted extraction with 1.5% Na2CO3 and 1% NaOH; column: Metrosep A Supp 10 - 250/4.0 (6.1020.030); eluent: 0.25 mol/L (NH4)2SO4, 0.05 mol/L NH4OH, 0.6 mL/min; column temperature: 25 °C; sample volume: 1000 μL; post-column derivatization with 2 mmol/L 1,5-diphenylcarbazide/10% methanol/0.5 mol/L H2SO4; flow rate post-column reagent: 0.2 mL/min; UV/VIS detection at 540 nm
33Heavy metals in the particulate matter byvoltammetryThe heavy metals (e.g., lead, cadmium, and zinc) con-tained in particulate matter and dust deposits not onlyact directly on the respiratory system through inhaled air,but can also accumulate in soil and water as a result ofwet and dry deposition from the air and thus enter thefood cycle, and from there make their way into the or ganism. Apart from having a carcinogenic effect, heavyme damage especially the kidneys, liver, nervous sys- talstem, and cardiovascular system.Although the ambient air concentrations of heavy metalshave decreased considerably since the ban on leadedgasoline, particulate matter samples from sites exposedto traffic and industry still show noticeable amounts oflead, arsenic, and cadmium. Directive 2008/50/EC of theEuropean Parliament and of the Council on ambient airquality and cleaner air sets limits and targets for variousconcentrations of harmful substances in the air.With the help of voltammetry, heavy metals in the air canbe determined right down to trace levels.
Semicontinuous methods34 PILS – Particle Into Liquid Sampler Compared with the filter methods, the Particle Into Liquid PILS can be connected directly to a wide range of analy- Sampler (PILS) allows a much higher time resolution. Semi zers. Apart from coupling to ion chromatographs and c ontinuous measurements are possible approximately every vol tammetric measuring stands, which is described in this 15 minutes. This high time resolution allows changes in brochure, coupling to TOC or ICP analyzers is also wide- the aerosol composition to be correlated with meteoro- spread. Whereas the former determines the total organic logical and other data. Furthermore, there is no need for carbon in the aerosol, ICP is used for multi-element ana complicated and error-prone manual sample preparation, lysis. Offline sampling with an autosampler is also possible. and no hassle of storing samples. Semicontinuous determination of anions and The way PILS works is simple. At the intake a size-selec- cations by PILS-IC tive cyclone limits the particle size of the aerosols to a Coupling with ion chromatography allows climate-relat- maximum of 1, 2.5 or 10 μm (PM1, PM2.5, PM10), as requi ed water-soluble anions and cations in the aerosol to be red. The aerosols then enter a condensation chamber, determined. This enables important conclusions to be where they meet a supersaturated water vapor phase. drawn about the precursors and thus about the question Within a very short time they grow into droplets, are se of whether particles are emitted directly – as in the case parated out, and transported to the ion chromatograph of the primary sea salt aerosols (NaCl) – or whether the or the voltammetric measuring cell by a carrier fluid. materials are secondary aerosols that are not formed until a chemical reaction has taken place (e.g., sulfate aerosols). lithium; 80.0 µg/L bromide; 920.0 µg/L 2.8 765.5 2.6 766.0 2.4 Conductivity [µS/cm] Conductivity [µS/cm] ammonium; 91.1 µg/L 2.2 766.5 nitrate; 295.2 µg/L 2.0 767.0 potassium; 11.4 µg/L 1.8 chloride; 11.0 µg/L sodium; 6.2 µg/L calcium; 7.0 µg/L sulfate; 31.5 µg/L 767.5 nitrite; 2.5 µg/L 1.6 1.4 768.0 1.2 768.5 1.0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Time [min] Time [min] Anions in an aerosol sample (PM2.5) from outside air; the internal Cations in an aerosol sample (PM2.5) from outside air; the internal standard is LiBr; column: Metrosep 5 - 100/4.0 (6.1006.510); standard is LiBr; column: Metrosep C 4 - 100/4.0 (6.1050.410); eluent: 3.2 mmol/L Na2CO3/1.0 mmol/L NaHCO3, flow rate: eluent: 1.7 mmol/L HNO3, 0.7 mmol/L dipicolinic acid, flow rate: 0.7 mL/min; sample volume: 250 μL 0.9 mL/min; sample volume: 250 μL
Anions and cations by PILS-ICSemicontinuous determination of anions and cations in be detected immediately. The falling nit rate and ammo- 35atmospheric aerosols allows high time resolution, which nium concentrations between 12.00 a.m. and 1.00 p.m.enables the concentration to be recorded over a prolon are a consequence of the lower volume of traffic duringged period. Sudden changes in aerosol composition can the lunch break. Semicontinuous ion chromatographic determination of anion and cation concentrations in air samples from Herisau (Switzerland) by a PILS sampling systemHeavy metals by means of PILS-VAThe combination of the PILS aerosol collector with the of the aerosols: the concentrations of copper and cad-797 VA Computrace allows semicontinuous determina- mium in the air increase steadily over several days until ittion of various heavy metals (Cd, Pb, Zn, Cu, Ni, Co, etc.) starts to rain and a large proportion of the copper andin particulate matter. The high time resolution picks up cadmium are washed out of the air (wet deposition).even the smallest changes in the chemical composition Semicontinuous voltammetric determination of heavy metal concentrations (Cd, Pb, and Cu) in air samples from Herisau (Switzerland) by a PILS sampling system
36 Standard ions and heavy metals by PILS-IC-VA Simultaneous coupling with several analyzers is also pos- tograph for anion and cation determination and to a sible: in PILS-IC-VA the particles brought into solution are voltammetric measuring stand for determination of the conveyed in three streams to a two-channel ion chroma- heavy metal ions. Semicontinuous ion chromatographic determination of the anion and cation concentrations and voltam- metric determination of the heavy metal concentrations in air samples from Herisau (Switzerland). To simulate contamination events, sparklers that had been previously immersed in heavy metal salt solutions were burnt.
MARGA – Monitor for AeRosols and GAsesWhile the PILS aerosol collector enables semicontinuous where they meet a supersaturated steam phase, absorb 37determination of water-soluble ions in aerosol particles, an increasing amount of water as condensation seeds,MARGA (Monitor for AeRosols & Gases in Ambient Air) grow as a result of this, and are finally separated outoffers the option of also analyzing the composition of mechanically in a glass spiral (cyclone). The resulting solu-the water-soluble gas phase. As in the PILS system, air is tion is collected, and its anion and cation content is desucked into the analyzer through a size-selective particle ter mined hourly by the integral ion chromatograph.separator. Together, gases and aerosols enter a rotatinggas-phase diffusion separator (denuder), where the for- A MARGA system provides exact results every hour. Bemer are absorbed in a thin layer of water (NH4+, SOx, cause the system can work for days on end without theNOx, HCl), and sent to the ion chromatograph for deter- addition of new solutions, MARGA is ideal for field use inmination of the anions and cations. From the denuder, remote regions.the aerosols go to the Steam-Jet Aerosol Collector (SJAC), The MARGA system at a glance. At the top is the box with the air inlet, diffusion separator, Steam-Jet Aerosol Collector (SJAC), eluent container and some pumps; in the middle are the sam- ple delivery and the two ion chromatographs for determination of anions and cations. The bottom shelf accommodates vari- ous storage containers, an uninterruptable power supply, and a vacuum pump. www.metrohm-applikon.com