Specialty Chemical Manufacturing Expertise Since 1928GFS ChemicalsAnalytical Reagents& Solutions2006-2007 PRODUCT CATALOG
pH Reference Buffers and Primary Standards ANALYTICAL REAGENTS&SOLUTIONSpH Reference Buffers used with confidence for all ucts but also new unit sizes,GFS Chemicals’ pH Buffers are applications because stan- including bulk containers, andmanufactured from the finest dardization is performed case pricing. Certificates ofhigh-purity water and reagent using the most trusted instru- Analysis are provided withgrade chemicals. They are ments in the business – Orion, every shipment and includestandardized at 25°C against Beckman-Coulter, and Hanna, NIST Traceability.NIST reference materials to a to name a few. For simplicity,tolerance of 0.01 on Buffers all common buffers are the Primary Standards4.00, 7.00, and 10.00 and to a same price regardless of pH Even with the automation oftolerance of 0.02 on all other or if color coded. This catalog so many lab methods, itbuffer ranges. Our buffers are features not only new prod- remains essential to verify analytical standard solutions. For over 75 years, GFS Chemicals has provided pri- mary standards to support analytical chemists worldwide with traceability as well as the confidence that their results are accurate. GFS continues to support chemists performing such titrations as acid-base, redox, complexometric, and many others. Following is a list of many common primary stan- dards manufactured by GFS. Throughout the catalog, many others are listed and we wel- come inquiries for your unique standards.
For acid-base: diphenylguani- involving the formation of dine, constant boiling perchlo- complex ions. ric acid, potassium acid phthalate, potassium bi- Of several substances which iodate, sulfamic acid, and can be used as standard solu- tris-hydroxymethyl- tions in such analyses, sodi- aminomethane. um ethylenediamine- tetraacetate (EDTA) is one ofANALYTICAL REAGENTS&SOLUTIONS For redox titrimetry the fol- the most satisfactory in that it lowing are listed as primary forms highly stable complex standards: ceric ammonium ions with calcium, magnesium nitrate, ferrous ethylenedi- and numerous other metals. A ammonium sulfate, electrolyt- solution of disodium dihydro- ic iron, potassium bi-iodate, gen ethylenediaminetetra- potassium dichromate, and Find these items by name in acetate (pH 5.5) is usually sodium oxalate. the alphabetical listing in this used as the standard solution. catalog. For more information, For complexation titrimetry request GFS Chemicals publi- The most common of such (EDTA): calcium carbonate, cation No. 497, Standard titrations is the determination disodium dihydrogen ethyl- Substances and Solutions (see of calcium and magnesium, as enediaminetetraacetate dihy- page facing inside back cover). in analysis of waters for hard- drate, and magnesium iodate ness, or of limestone. The tetrahydrate. Complexometric end-point may be detected in Titration Reagents various ways, the most com- Other specially prepared pri- A spectacular advance in ana- mon utilizing the dyestuff mary standards include sodi- lytical chemistry was the Eriochrome Black T. This um chloride for argentimetric introduction of ethylenedi- dyestuff has the unique prop- titrations; and cobalt sulfate aminetetraacetate as a stan- erty of itself forming a com- for volumetric and colorimet- dard solution in titrations plex ion with magnesium. On ric analyses. titration, the EDTA first unites pH Values of Buffers at Various Temperatures 25 o 0o 5o 10 o 20o 30o 40o 50o 60o 70o 80o 90o 1.68 1.67 1.67 1.67 1.67 1.68 1.69 1.71 1.72 1.74 1.77 1.79 4.01 4.00 4.00 4.00 4.00 4.02 4.03 4.06 4.08 4.13 4.16 4.21 6.86 6.98 6.95 6.92 6.87 6.85 6.84 6.83 6.84 6.85 6.86 6.88 7.00 7.11 7.08 7.06 7.01 6.98 6.98 6.97 – – – – 9.18 9.46 9.40 9.33 9.23 9.14 9.07 9.01 8.96 8.92 8.89 8.85 10.01 10.32 10.25 10.18 10.06 9.97 9.89 9.83 – – – –
with the calcium and metals with EDTA.magnesium ions insolution and then Three primary stan-pulls the magnesium dard materials areaway from the available for titrimet-dyestuff-magnesium ric work with EDTA.complex resulting in a Ordinary reagentcolor change from red grade calcium carbon- ANALYTICAL REAGENTS&SOLUTIONSto blue. The titration ate contains sufficientis carried out at a pH magnesium to make itof 10 and yields the unacceptable as a pri-sum of the calcium mary standard but aand the magnesium special, low-magne-present. sium grade is avail- able, Item# 337. AboutAqueous solutions of the only goodEriochrome Black T primary standarddo not keep and magnesiumanother indicator, Calmagite, tion of certain blue dyes, thy- compound is magnesiumwas introduced for the EDTA molphthalein or bromthymol iodate tetrahydrate, describedtitration of calcium plus mag- blue, gives a somewhat more in 1962 by Lindstrom andnesium. The color change of satisfying color change at the Stevens; this material is avail-Calmagite at the end-point is end-point. able as Item# 348. Disodiumalso from red to blue but the Dihydrogen Ethylenediamine-colors are clearer and the The end-point with Calcein tetraacetate Dihydrate, theend-point sharper. Aqueous may be detected also by the reagent used to prepare EDTAsolutions of this indicator are disappearance of the fluores- solutions, is itself a good pri-stable indefinitely. Carried out cence under ultraviolet illumi- mary standard when properlyunder slightly different condi- nation of the calcium salt. prepared, item #365.tions, pH 12, and with the Calcein is prepared by theindicator Calcein, calcium action of formaldehyde andalone may be determined in iminodiacetic acid on fluores-the presence of even large cein. It is typical of a class ofamounts of magnesium. This indicators known at “metalflu-procedure may be applied to orochromic” indicators.the determination of calciumin water and in limestone. Another indicator of this classCalcein modified by the addi- is Calcein Blue (ß-methyl-umbelliferonemeth- ylene- iminodiacetic acid) which is useful in the titration of copper, cobalt and other
High-Purity Quaternary Ammonium SaltsANALYTICAL REAGENTS&SOLUTIONS HPLC and processes and protocols that examples and broader appli- Analytical Grade Quats have stringent purity require- cations include: As a chemical manufacturer ments; this includes suitabili- • Bu4NOH (TBA hydroxide) - serving analytical labs world- ty for use as polarographic supporting electrolyte; wide, the addition of product electrolytes and/or HPLC phase-transfer catalyst; lines targeted directly to that applications. Both methanolic titrant market is one of our top prior- and aqueous hydroxide solu- • Bu4N(H2PO4) (TBA phos- ities. Hundreds of GFS prod- tions feature: phate) - ion-pair chromatog- ucts fit this product profile, • very high alkalinity raphy; buffering medium and two groups deserve spe- • very low chloride • Me4NCl (TMA chloride) - cial mention: ultrapure (99.99 • virtual freedom from alkali USP/NF polarographic test to 99.9999%) materials and metal impurities reagent; catalyst; inhibitor standard solutions, (for exam- • low ash • Me4NOH (TMA hydroxide) - ples, see pp. 96-97) and synthetic intermediate; Quaternary Ammonium salts The EARG line fully comple- precipitant; etchant; catalyst and solutions (QUATS). ments the traditional GFS • Et4NPF6 (TEA hexafluo- QUAT line, which has found widespread industrial and rophosphate) - fluoriding GFS has a long history with agent; biocide precursor QUATS; our production of commercial use. Some key tetraalkylammonium perchlo- rates reflects the company’s dominant market position in perchloric acid and inorganic perchlorate salts. The GFS QUAT line now includes Electrometric and Analytical Reagent Grade (EARG) prod- ucts. The EARG line of high purity QUATS have characteristic properties that are of particu- lar interest to chemists and technicians dealing with
Many other products areavailable in various purities,and we make custom formula-tions on a regular basis.The chemical literaturereflects a broad and ongoinginterest in QUATS, including ANALYTICAL REAGENTS&SOLUTIONSthe perchlorate salts. Electro-analytical studies oftetraethylammonium perchlo-rate solutions have elucidatedthe nature of cation adsorp-tion at mercury electrodes.1A wide range of tetrabutyl-ammonium perchlorate solu-tions have been examined forconductometric and dielectricbehavior.2 Electronic conduc-tion has also been used tostudy the behavior of thenitrobenzene anion radical inthe presence of tetrabutylam-monium perchlorate in solidnitrobenzene.3In the final analysis, it’s allpart of the greater productselection and personal servicethat you’ve come to expectfrom GFS.1. Journal of ElectroanalyticalChemistry 1989, vol.270 pp. 381-393.2. Acta Chemica Scandanavia 1989,vol.43, pp. 103-115.3. Bulletin of the Chemical Society ofJapan 1989, vol.62, pp. 3413-3416.