Abstract: A reagent for pH-metric acid number determination in a petroleum oil with low acid numbers (AN≦0.03 mg KOH/g oil) includes a salt of a strong base and a weak acid, and, an alkali in a mixture of water and an alcohol. The salt of a strong base and a weak is, preferably, sodium benzoate in a concentration of 0.02 to 0.1 M. The alcohol is, preferably, isopropanol in a concentration of from 50% to 80% by volume. The alkali is, preferably, an hydroxide and, most preferably, potassium hydroxide. The alkali should be adjusted to provide a pH′o, which is the pH of an equivalence-point on a titration curve of a strong acid added to a test portion of sodium benzoate, water and isopropanol.

Abstract: A reagent for the acid value determination in oils. The reagent contains a tertiary amine, such as triethanolamine, in a water-alcohol mixture as solvent. Preferred is isopropanol/water. The reagent allows determinations of acid values in oils in a two phase system. The use of the reagent is based on a pH-metric technique with conditional pH-measurement before and after the addition of an oil sample to the reagent.

Abstract: A novel method for preparation of electrodes at a low temperature from electroconducting refractory powder materials. The electrodes are useful for analytical purposes. The method is based on cold pressing of the powders, wetted with solution of a polymer and placed into a disposable frame of the same polymer, with the help of a laboratory hand device producing a relatively small pressure. Control of the end of pressing is done by means of measurement of the electrode resistance. A puncheon serves as a current conductor. Electrodes thus prepared have a low resistance, a high sensitivity and stability. In comparison with glassy carbon electrodes, the most widely applied ones in electroanalytical chemistry, the novel electrodes are cheaper, yet not inferior to such glassy carbon electrodes, and even sometimes better.

Abstract: A method for determining the acid value of oilseeds. A reagent kit for the rapid extraction of the free fatty acids from oilseeds which consists of reagents: "A" and "B". Reagent "A" contains a tertiary amine (such as triethanolamine) in water and an alcohol--hydrocarbon mixture as solvent. Preferred is water/isopropanol/heptane. Reagent "A" allows rapid (1-2 min) solid-liquid extraction of the free fatty acids and some other acids from oilseeds. Reagent "B" contains a strong acid and an inorganic salt in water. Reagent "B" enables the rextraction (liquid-liquid; about 5 min) of the free fatty acids only into a separate hydrocarbon phase, which can be used for the acid value determination.

Abstract: Novel reagents and the rapid technique were developed for the simultaneous determination of water and ene-diols or thiols in chemical products, drugs and other materials which are inaccessible for direct K. Fischer titration. The reagents include iodine, tetramethylammonium iodide or potassium iodide, non-toxic organic or inorganic base adapted to provide a pH in range of 5.5 to approximately 8.0 (diethanolamine, thriethanolamine, sodium acetate or/and urea) in methanol or another alcohol mixed with N,N-dimethyl-formamide, or with formamide, or with dimethyl sulfoxide and N,N dimethylformamide mixture as a solvent. The use of the reagents is based on the consecutive titration first a) of an ene-diol or thiol by the novel reagents and then b) of water by a conventional K. Fischer reagent in the same cell in a system protected from water vapour and oxygen, with the help of the double burette for electrometric location of the end point in both titrations (or a multistage titroprocessor).

Abstract: A device for batch injection stripping voltammetric analysis of metal traces, of very high sensitivity. This sensitivity extends down to about 0.03 to 0.3 ppb for certain metals. The microanalysis can be carried out at a high rate and in addition to the high sensitivity is characterized by accuracy and high reproducibility. One of the main features is a novel microcell with a rotating working electrode of the mercury coated graphite type.