The document provides a comprehensive list of electrodes suitable for pH measurement across various applications, including laboratory analysis, environmental monitoring, and industrial processes. It details specific electrodes, their order numbers, and the sample types they are designed for, such as water, soil, food products, and solvents. Additionally, it includes practical tips on care and maintenance for different electrode types and their storage conditions.

1. Electrodes for pH measurement
Which electrode for which application?
Application Specifics Electrode Order no. Application Specifics Electrode Order no.
Standard laboratory, various samples, pH 0...14, T = 0...100 °C Unitrode 6.0258.600 Bleaching & dye baths Profitrode 6.0255.100
General
Routine analysis in similar samples, pH 1...11 Ecotrode Gel 6.0221.600 Leather, paper, Dampening solutions (offset printing), glue Unitrode 6.0258.600
Water Demineralized, drinking and sea water, weakly buffered solutions Aquatrode Plus 6.0257.000 textile industry Leather, paper, textiles (surface measurement) Flat membrane 6.0256.100
General Unitrode 6.0258.600 Washing liquors Viscotrode 6.0239.100
Waste water
Sulfide-containing waste water Profitrode 6.0255.100 Dye baths, ink, wood stain, lacquers Profitrode 6.0255.100
Soil samples Surface measurement or aqueous suspensions Flat membrane 6.0256.100
Paints, lacquers, Dispersions, emulsions, resins, suspensions Unitrode 6.0258.600
Culture media, small volume samples Biotrode 6.0224.100 solvents Paint (surface) Flat membrane 6.0256.100
Fertilizers Unitrode 6.0258.600 Non-aqueous, polar solvents EtOH-Trode 6.0269.100
Agriculture,
Liquid manure Profitrode 6.0255.100
plant breeding Electroplating, General Profitrode 6.0255.100
Nutrient solutions Viscotrode 6.0239.100
metal Acidic electroplating baths Unitrode 6.0258.600
Protein-containing solutions Porotrode 6.0235.200
processing Cutting-oil emulsions Viscotrode 6.0239.100
General Unitrode 6.0258.600
Concentrated acids Profitrode 6.0255.100
Protein-containing food, beer Porotrode 6.0235.200
Food, Photographic baths Profitrode 6.0255.100
Penetration measurement (dough, cheese, meat) Spearhead 6.0226.100
stimulants Emulsions, suspensions, dispersions Unitrode 6.0258.600
Drinking water Aquatrode Plus 6.0257.000
Samples at pH >12 Unitrode 6.0258.600
Juices, wine, spirits Unitrode 6.0258.600
Creams, liquid formulations, medicinal syrups, mouthwashes, raw materials Viscotrode 6.0239.100 Temperature 50...80 °C Unitrode 6.0258.600
Pharmaceutical Dialysis solutions, urine Unitrode 6.0258.600 Temperature 80...100 °C Unitrode (Idrolyte) 6.0258.600
industry, Gastric juice, serum, small-volume samples Biotrode 6.0224.100 Special Ion-deficient solutions, weakly buffered solutions Aquatrode Plus 6.0257.000
biology Infusion solutions Aquatrode Plus 6.0257.000 applications Non-aqueous, polar solvents EtOH-Trode 6.0269.100
Protein-containing solutions Porotrode 6.0235.200 Penetration measurement Spearhead 6.0226.100
Shampoos, emulsions, shower gels, mouth rinses, perfumes Viscotrode 6.0239.100 Protein-containing solutions Porotrode 6.0235.200
Cosmetics Make-up Micro-electrode 6.0234.100 Small volume samples Biotrode 6.0224.100
Skin (surface measurement) Flat membrane 6.0256.100 Flat membrane 6.0256.100
Detergents, General Viscotrode 6.0239.100 Surface measurements Flat membrane 6.0256.100
surfactants Samples with pH >10 Profitrode 6.0255.100 Biofuels / E85 EtOH-Trode 6.0269.100

2. Practical tips, care and maintenance
Spearhead Flat membrane
Unitrode Ecotrode Gel Aquatrode Plus Profitrode Viscotrode Biotrode Porotrode EtOH-Trode
pH electrode pH electrode
Combined pH glass Combined pH glass Combined pH glass Combined pH glass Combined pH glass Combined pH glass Combined pH glass Combined pH glass Combined pH glass Combined pH glass
electrode, fixed ground- electrode, twin-pore electrode, fixed ground- electrode, ground-joint electrode, ground-joint electrode, plied Pt-wire electrode, twin-pore electrode, ceramic electrode, fixed ground- electrode, ground-joint
joint diaphragm diaphragm. joint diaphragm diaphragm diaphragm diaphragm diaphragm capillary diaphragm joint diaphragm diaphragm
• very low alkali error • for routine • for low-conductivity • for difficult matrices • for viscous, protein- • for small-volume • for measurement • for protein-con- • for pH-measurement • for pH-measurements
• insensitive to con- measurements in or weakly buffered • easy-to-clean dia- or sulfide-contain- samples in semi-solid samples taining or viscous on surfaces (e.g. skin, in EtOH
tamination similar samples. solutions phragm ing solutions • for protein-con- • maintenance-free samples leather, paper, • double-junction
• high temperature • with life-time indicator • very rapid response • double-junction • easy-to-clean dia- taining samples reference electrolyte • reference electrolyte: textiles) construction
resistance • maintenance-free • insensitive to construction phragm and samples con- (gel) Porolyte2) • very rapide response
reference electrolyte contamination taining organic • easy-to-clean pinhole (6.2318.000)
Ordering info (gel) Ordering info Ordering info solvents diaphragm • easy-to-clean
6.0259.100 without cable, 6.0253.100 without cable, 6.0255.100 (fitting • shaft diameter 3 mm capillary diaphragm
plug-in head G plug-in head G lenght: 113 mm) without • reference electrolyte:
cable, plug-in head Idrolyte1)
6.0258.010 with 6.0257.000 with Pt 1000 (6.2308.040)
Pt 1000 fixed cable, plug fixed cable, plug F+2 x 6.0255.110 (fitting
F+2 x 2 mm Ordering info 4 mm lenght:170 mm) without Ordering info Ordering info Ordering info Ordering info Ordering info Ordering info
cable, plug-in head G
6.0258.600 with Pt 1000, 6.0221.600, without 6.0239.100 without cable, 6.0224.100 without cable, 6.0226.100 without cable, 6.0235.200 without cable, 6.0256.100 without cable, 6.0269.100 without cable,
plug U (without cable) cable, plug-in head U 6.0255.120 (fitting plug-in head G plug-in head G plug-in head G plug-in head G plug-in head G plug-in head G
lenght: 310 mm) without
cable, plug-in head G
Use 6.2308.040 Idrolyte1) Store in c(KCl) = sat. Store in 6.2323.000 Store in bridge electrolyte. Store in 6.2323.000 Store in 6.2308.040 Store in 6.2308.000 Store in 6.2323.000 Store in 6.2323.000 If reference electrolyte is
for measurement at Do not wipe electrode! storage solution only! Do not wipe electrode! storage solution. Idrolyte1). KCl sat. storage solution. storage solution. c(KCl)= 3 mol/L store
temperatures 80...100 Add a small drop of dist. in 6.2324.000 storage
°C or to suppress protein Rinse with water/ethanol Do not wipe electrode! For cleaning/care 6.2325.000 Do not wipe electrode! Do not wipe electrode! Rinse with water or Rinse with water or
to remove contamination. For cleaning / care pHit Kit is recommended. For cleaning / care For cleaning / care ethanol to remove ethanol to remove water on the surface to be solution.
precipitation by KCl. contamination. contamination. measured. Do not wipe electrode!
6.2325.000 pHit Kit is Lift sleeve ring for cleaning 6.2325.000 pHit Kit is 6.2325.000 pHit Kit is
Do not wipe electrode! recommended. ground-joint diaphragm. recommended. recommended. Do not remove con- Do not wipe electrode! Do not wipe electrode! For cleaning / care
Unitrodes filled with Use soft cloth or brush to re- tamination in pinhole 6.2325.000 pHit Kit is
move any adhering material.
Lift sleeve ring for For cleaning / care For cleaning / care
c(KCl) = 3 mol/L should cleaning ground-joint diaphragm with a 6.2325.000 pHit Kit is 6.2325.000 pHit Kit is recommended.
be stored in 6.2323.000 If the sleeve ring is blocked, diaphragm. Use soft cloth needle. The gel electro- recommended. recommended.
8.000.6001EN – 2010-01
storage solution. place the electrode in hot or brush to remove any lyte might be damaged.
For cleaning / care water for a few minutes adhering material. Remove electrode slowly
6.2325.000 pHit Kit is and try again. from sample to avoid
If the sleeve ring is underpressure in the gel
recommended. Spare ground-joint blocked, place the electrolyte.
diaphragm for Profitrodes electrode in hot water
6.0255.1X0: for a few minutes and try
order no. 6.1243.020 again.
1) Idrolyte is a glycerol-based electrolyte whose ion activity corresponds to that of c(KCl)= 3 mol/L.
2) Porolyte is a KCl solution that has been gelled by polymerization and is used in electrodes with a capillary diaphragm (Porotrode). www.pH-measurement.com