Biomedical subjects
Publications and source records attributed to R Matissek.
Tetrachloroethene (perchloroethylene) from dry-cleaning units may contaminate adjacent flats in the same building. Increased concentrations of tetrachloroethene have been found in foodstuffs in homes situated above dry cleaning units and in foodstuffs from groceries located neat drycleaning units. The concentrations were extremely high in foods rich in fat.
An outline will be given on chemical changes in substances contained in food due to the use of technological processes. The facts about hydrolytic alteration of carbohydrates, lipids and protein as well as changes due to oxidation on lipids and phenolic components will be explained. Changes caused by non-enzymic browning reaction (Maillard-Reaction) and the formation of flavouring and brown pigments in food play a major role in food quality variations as do changes due to storage and processing. A report will be given, using selected examples, on the Maillard-Reaction, the formation of products as well toxicological and physiological characteristics.
Methyl isothiazolone formulations (Kathon CG) promoted as preservatives in the cosmetic field were investigated for their organic components by capillary gas chromatography/mass spectrometry. 2-methyl-3(2H)-isothiazolone and 5-chloro-2-methyl-3(2H)-isothiazolone were identified as effective major components and 4,5-dichloro-2-methyl-3(2H)-isothiazolone, 3-chloro-N-methyl-propionamide and dichloro-N-methyl-acetamide as minor components. Various methods like thin-layer chromatography with chemical and UV-detection, high-performance thin-layer chromatography using direct optical measurement, capillary gas chromatography with nitrogen selective thermionic detector, high-performance liquid chromatography with UV- resp. diode-array-UV-detector and UV-spectrometry were applied for detection and identification of the compounds. For quantitative determination it was necessary to obtain the corresponding purified isothiazolones as reference compounds. Commercial formulations were fractionated by reversed phase flash chromatography. Then the exact composition of the fractions obtained was determined by an absolute method, based on chemical reaction on a semi-micro scale. These solutions were used as reference for calibration. For quantitative determination of 2-methyl-3(2H)-isothiazolones reversed phase HPLC has proved to possess good reliability using the internal standard method (2-acetyl-5-chlorothiophen). Response factors and the relative calibration curves for this method were ascertained. A special technique based on extractive separation and purification by flash chromatography was developed for the isolation of 2-methyl-3(2H)-isothiazolone and 5-chloro-2-methyl-3(2H)-isothiazolone from cosmetic products. The average recovery rates and detection limits are given. The method was tested on several different commercial cosmetics. The samples contained between 5.5 and 39.4 mg/kg of methylisothiazolones.
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The different approaches to achieving skin tanning with emphasis on natural tanning, due to UV radiation of the sun or solaria, and artificial tanning through tannings agents are described. In contrast to the artificial tan the natural tan is a protection against UV radiation and is caused by pigmentation (melanin formation). The artificial tanning is based on a chemical reaction usually by means of dihydroxy acetone (melanoidin formation). Reaction mechanisms by both agents are reported. The determination of dihydroxy acetone in cosmetic tanning preparations by TLC, GC, HPLC, enzymatic tests and by a new method for capillary GC including sample preparation is described. When exceeding the natural protection mechanisms the skin should be protected by physico-chemical measures. The active principles in sunscreens are the UV filtering substances. UV filters permitted in the EG are listed. 2-Hydroxy benzophenone is used as an example to explain the mechanism of UV filtering substances. Analysis of UV filtering substances in cosmetic sunscreens by TLC, GC, HPLC is described as well as a fast and simple method for separation of lipophilic UV filters followed by capillary GC determination.