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Biomedical subjects

T Groh

Publications and source records attributed to T Groh.

6 recordsLinked to original sources
PubMed1998

Rapid urinary iodide test.

Assessment of iodine deficiency and monitoring of iodine supplementation programs demands rapid, simple and cost-effective methods for the determination of urinary iodide concentrations. We propose a rapid test based on the iodide-catalyzed oxidation of 3,3',5,5'-tetramethylbenzidine by peracetic acid/H2O2 to yield colored products. The color of the chemical reaction is compared with color categories of a pictogram corresponding to three ranges (<10, 10-30, and >>30 microg/100 mL) of iodide concentrations. The test is very easy to perform and does not require any instrumentation or apparatus. Sample preparation is simple and consists in the removal of interfering substances by disposable columns, 65 x 10.5 mm, packed with specifically prepared activated charcoal. For comparison with a reference method for measuring urinary iodide (HPLC), we determined the iodide concentrations of 370 random (untimed) urine samples from consecutive patients by both HPLC and the rapid test. The results obtained by both methods are in close agreement with respect to classification of the samples according to the above three ranges, with a maximum difference of <5% for each range. This rapid test is therefore very well suited to epidemiological surveys of iodine deficiency especially in developing countries.

Benzidines↗
PubMed1998

Rapid urinary iodide test.

Assessment of iodine deficiency and monitoring of iodine supplementation programs demand rapid, simple, and cost-effective methods for the determination of urinary iodide concentrations. We propose a semiquantitative rapid test, based on the iodide-catalyzed oxidation of 3,3',5,5'-tetramethylbenzidine by peracetic acid/H2O2, to yield colored products. The color of the chemical reaction is compared with color categories of a pictogram corresponding to three ranges: <100, 100-300, and >300 microg/L (<0.79, 0.79-2.36, and >2.36 micromol/L) of iodide concentrations. The test is very easy to perform and does not require any instrumentation or apparatus. Sample preparation is simple and consists of the removal of interfering substances by disposable columns, 65 x 10.5 mm, packed with purified activated charcoal. For comparison with a reference method for measuring urinary iodide, by high-performance liquid chromatography, we determined the iodide concentrations of 370 random (untimed) urine samples from consecutive patients by both high-performance liquid chromatography and the rapid test. The results obtained by both methods are in close agreement, with respect to classification of the samples according to the above three ranges, with a maximum difference of less than 5% for each range. Median (y) values of a given distribution of urinary iodide concentrations can be calculated from the percent (x) of samples below 100 microg/L (0.79 micromol/L) using the regression equation: y = 179.78 - 1.60x. This rapid test, therefore, is suited to epidemiological surveys of iodine deficiency, especially in developing countries.

Chromatography, High Pressure Liquid↗
PubMed1992

Selective influencing of the migration time of SO4(2-) by forming neutral species with Pb2+ in capillary zone electrophoresis.

Organic and inorganic anions are analyzed using capillary zone electrophoresis with indirect fluorescence detection. As electrolyte 2,5-dihydroxybenzoic acid is used. By adding Pb2+ to the electrolyte the migration time of SO4(2-) can be selectively influenced and the separation of Cl- and SO4(2-) considerably improved. The fluorescence intensity of 2,5-dihydroxybenzoic acid increases in the presence of Pb2+ up to a concentration of 6*10(-4) mol/L Pb2+. Limits of detection in the lower mumol/L range were obtained.

Anions↗