Sb is determined in polyethylene terephthalate (PET) after digestion in sulfuric acid and hydrogen peroxide. The application is carried out with anodic stripping voltammetry (ASV) in hydrochloric acid.

AN-V-114

Cobalt in polyethylene terephthalate (PET)

Co is determined in polyethylene terephthalate (PET) after digestion in sulfuric acid and hydrogen peroxide. The application is carried out with adsorptive stripping voltammetry (AdSV) in ammonia buffer with dimethylglyoxime (DMG) as complexing agent.

AN-V-113

Titanium in polyethylene terephthalate (PET)

Ti is determined in polyethylene terephthalate (PET) after digestion in sulfuric acid and hydrogen peroxide. Adsorptive stripping voltammetry (AdSV) with mandelic acid as complexing agent is used for this application.

AN-V-062

4-Carboxybenzaldehyde in polyterephthalic acid

4-Carboxybenzaldehyde can be reduced directly on the DME in an solution containing ammonium

AN-V-003

Nickel, cobalt and iron in polyterephthalic acid solution

Determination of Ni, Co and Fe in a PTA solution containing HCl.

AN-V-002

Chromium, manganese and titanium in polyterephthalic acid solution

Determination of Cr, Mn and Ti in a PTA solution containing HCl.

AN-U-017

Chromate in wastewater using conductivity and subsequent UV/VIS detection after post-column reaction (diphenylcarbazide method)

Determination of chromate in wastewater using anion chromatography with conductivity detection after chemical suppression and UV/VIS detection after post-column reaction (PCR) with diphenylcarbazide reagent.

AN-U-015

Chromium(VI) in a leather extract

Determination of chromium(VI) (chromate) in leather extract using anion chromatography with UV/VIS detection after post-column reaction (PCR) and inline dialysis for sample preparation.

AN-T-039

Free alkali in sodium hypochlorite

Determination of free alkali in sodium hypochlorite by potentiometric titration with hydrochloric acid using a combined glass electrode.

AN-T-025

Hydrogen peroxide in aqueous solutions

Determination of hydrogen peroxide in aqueous solutions by potentiometric titration with permanganate using the combined Pt electrode.

AN-S-243

Chloride, chlorate and sulfate in soda lye (50% sodium hydroxide) using Metrohm Inline Sample Neutralization

Determination of chloride, chlorate and sulfate in soda lye (50% sodium hydroxide) using anion chromatography with conductivity detection after sequential suppression and Metrohm Inline Neutralization.

AN-S-178

Five anions in lignin

Determination of chloride, sulfite, sulfate, oxalate and thiosulfate in lignin using anion chromatography with conductivity detection after chemical suppression.

AN-S-084

Chloride, phosphate, phosphite and sulfate in a dye solution

Determination of chloride, phosphate, phosphite and sulfate in a dye solution using anion chromatography with conductivity detection after chemical suppression.

AN-N-057

Chloride and sulfate in a reactive dye

Determination of chloride and sulfate in a reactive dye using anion chromatography with direct conductivity detection. Suppressed IC does not work as the dye is hydrolyzed in alkaline solution and releases sulfate.

AN-N-050

Chromium(VI) in a leather extract

Determination of chromium(VI) (chromate) in leather extract using anion chromatography with UV/VIS detection (540 nm) after post-column reaction (PCR) and inline dialysis for sample preparation.

AN-K-013

Water in organic peroxides

The water content of organic peroxides is determined according to Karl Fischer using two-component reagents. To prevent any unwanted side reactions the determinations are carried out at -20 °C.

AN-H-032

Standardization of ammonium ferrous sulfate solution

Standardization of 0.1 mol/L ammonium ferrous sulfate solution for use in thermometric titration of Cr(VI) solutions.

AN-H-030

Determination of chlorite by direct titration with thiosulfate

Determination of chlorite by direct thermometric titration with standard sodium thiosulfate solution. The procedure
was applied originally to the determination of chlorite in hide treatment solutions.

AN-H-020

Determination of chromium in leather waste solutions

Determination of chromium in leather waste solutions in the range between 1000 and 30,000 ppm

AN-C-045

Magnesium in ammonium sulfate

Determination of magnesium in ammonium sulfate using cation chromatography with direct conductivity detection.

AN-C-027

Calcium, magnesium and potassium in sodium carbonate

Determination of potassium, calcium and magnesium in sodium carbonate using cation chromatography with direct conductivity detection.

AN-C-003

Sodium, ammonium and potassium in hydrogen peroxide (H₂O₂)

Determination of sodium, ammonium and potassium in hydrogen peroxide without decomposition or matrix elimination using cation chromatography with direct conductivity detection.

AB-270

Synthesis of phenyl azonaphthol

The important class of azo dyes comprises more compounds than all other classes of dyes together. The azo compounds form the basis of many dyestuffs and pigments used in the textile, paper and wood industries today.

This Bulletin describes the automated synthesis of phenyl azonaphthol by diazotization of aniline and subsequent azo coupling with 2-naphthol. The 711 Liquino is used to control and monitor the whole process.

AB-230

Titrimetric/potentiometric determination of nonionic surfactants based on polyoxyethylene adducts using the NIO electrode

This Bulletin describes the titrimetric determination of nonionic surfactants based on polyoxyethylene adducts (POE adducts). The determination is based on the conversion of the nonionic surfactant into a pseudo-cationic compound, which is determined in a precipitation titration using sodium tetraphenylborate (NaTPB). A newly developed surfactant electrode, the NIO electrode, is used as the indicator electrode. It has been designed taking into account the characteristics of this titration and therefore yields reliable, fast and efficient determinations. This Bulletin covers determinations in raw materials, formulations and wastewater. Characteristics, possibilities, limitations and interferences are pointed out.

AB-196

Polarographic determination of formaldehyde

Formaldehyde can be determined reductively at the DME. Depending on the sample composition it may be possible to determine the formaldehyde directly in the sample. If interferences occur then sample preparation may be necessary, e.g. absorption, extraction, or distillation.
Two methods are described. In the first method formaldehyde is reduced directly in alkaline solution. Higher concentrations of alkaline or alkaline earth metals interfere. In such cases the second method can be applied. Formaldehyde is derivatized with hydrazine forming the hydrazone, which can be measured polarographically in acidic solution.

AB-136

Polarographic determination of styrene in polystyrene and copolymers

This Application Bulletin describes a simple polarographic method to determine monomeric styrene in polymers. The limit of determination lies at 5 mg/L. Before the determination, styrene is converted to the electrochemically active pseudonitrosite using sodium nitrite.

AB-105

Determination of lead and cadmium released from crockery and glassware

Lead and cadmium are metals which, when absorbed by the human organism over a long period in quantities exceeding 0.5 mg Pb or 0.05 mg Cd per day, will lead to toxic symptoms. For this reason, efforts are now being made in various countries to eliminate the most likely sources of these metals, whether in the air (exhaust gases from leaded motor fuels) or from eating and drinking vessels, or at least to reduce the risks of their being absorbed by human beings.

These metals are determined by extraction with 4% acetic acid followed by either atomic absorption spectrometry (AAS) or polarography. Of the two alternative methods, polarography offers certain advantages over AAS. Firstly, the apparatus required is generally lower in first cost and cheaper to maintain, and secondly, the polarographic method enables Cu, Cd, Pb, As and Sb to be determined together in a single operation. This Bulletin describes the determination of the above metals by means of differential pulse polarography.

AB-068

Potentiometric determination of carboxyl and amino terminal groups in polyamide fibers

Indication of the titration endpoint of the weakly alkaline or weakly acidic terminal groups in non-aqueous solution is frequently not easy. An improvement is possible by using a suitable titrant (TBAOH = tetrabutylammonium hydroxide for terminal carboxyl groups; perchloric acid for terminal amino groups).

An improvement in the evaluation can also be achieved by choosing benzyl alcohol as the solvent.

The choice of electrode combination and the measuring setup is also important. Differential potentiometry using the three-electrode technique results in a great improvement in titrations in poorly conducting solutions. Noisy signals are eliminated.

AB-008

Potentiometric titration of hypochlorite, chloride and chlorate in mixtures

Potentiometric titration methods are described for the determination of hypochlorite, chloride and chlorate in mixtures. Hypochlorite is titrated in alkaline solution with arsenite. Then, after acidification of the sample solution, the total chlorides (chloride plus chloride formed from hypochlorite) can be determined using silver nitrate. Chlorate is first reduced to chloride under acidic conditions with iron(II) ions and then also titrated as chloride. The individual components can also be determined by the methods described here.