PubMed Health⌕ Search

Biomedical subjects

J Angerer

Publications and source records attributed to J Angerer.

144 records · Page 8Linked to original sources
PubMed1977

[A method for the determination of bromide in urine with an ion-sensitive electrode (author's transl)].

A potentiometric method for determining the concentration of bromide in human urine is described. On account of its specificity and precision, this method is especially suited for the determination of slightly elevated bromide concentrations due to occupational exposure to alkyl bromides. The rate of recovery is 102.5 to 112.5%, and the variability coefficients lie between 5.8 and 8.6%. The detection limit is about 0.013 mmol/l. The concentrations of bromide in the urine of a group of normal persons lie between 0.059 and 0.162 mmol/l.

Adolescent↗
PubMed1976

[Gas chromatographic determination of formic acid in urine as carbon monoxide (author's transl)].

A gas chromatographic method for determining formic acid in human urine is described. The analytical reliability of this method fullfills the criteria of statistical quality control. The rate of recovery is 101.2 to 105.7% the variability coefficients lie between 2.9 and 7.2%. The selectivity of this method is demonstrated by analysing a group of components normally occuring in urine which did not interfere with the determination of formic acid. The detection limit of about 4.3 mumol/1 formic acid in urine permits the determination of the concentration of formic acid in the urine of normal persons. The concentrations of formic acid in the urine of a group of normal persons lies between 0 and 2.79 mmol/1. The average concentration was 0.39 +/- 0.60 mmol/1.

Carbon Monoxide↗
PubMed1975

[A new method for sampling and sample application in the ultra-trace of air by gas chromatography-mass spectrometry (author's transl)].

A new method is described for sampling and sample application in the ultra-trace analysis of air by gas chromatography-mass spectrometry. In this new technique, a preseparation occurs on the gas chromatographic column during sample application, since the atmospheric constituents that are co-condensed during sample application we call this method "Druckaufgabe" (pressure application). The method is not only of theoretical value. It has a potentially wide application to occupational and environmental problems.

Acetates↗
PubMedDate not supplied

Determination of carbon disulfide at the workplace by sampling on charcoal tubes--problems and solutions.

The aim of the study was to check the reliability and comparability of different analytical methods for ambient monitoring of carbon disulfide (CS2). A stationary sampling system, consisting of a charcoal sampling tube and pump, and two personal sampling systems, consisting of a charcoal sampling tube and a portable pump and of a diffusive charcoal sampler have been compared. The limits of quantification, within-series precision, between-series precision, recovery, and comparability of the methods were investigated. For passive sampling the recovery was determined by three different techniques. For a sampling time of 6 hours the limit of quantification was 0.2 ppm for the personal sampling and 0.01 ppm for the stationary sampling system. The within-series precision was between 5 and 8%. For personal sampling the between-series precision was between 9 and 12% using a passive sampler. The recovery ranged between 45 and 85% depending on the quotient of eluent volume and charcoal mass. The comparison of the two personal sampling methods in a field study using linear regression demonstrated with statistical certainty an excellent concordance of the methods. The study shows that particularly the method for determining air levels of carbon disulfide by passive sampling is associated with high systematic errors. If these errors are unknown or ignored they will result in highly underestimated exposure data for carbon disulfide.

Carbon Disulfide↗
PubMedDate not supplied

Gas chromatographic method for the simultaneous determination of S-p-toluylmercapturic acid and S-phenylmercapturic acid in human urine.

An analytical method for the simultaneous determination of S-p-toluylmercapturic acid (p-TMA) and S-phenylmercapturic acid (PMA) in human urine is described. PMA is a common biomarker for benzene exposure, whereas p-TMA is detected for the first time in the urine of workers occupationally exposed to toluene. Before analysis, the acidified urine samples were spiked with S-(p-fluorine)-phenylmercapturic acid as internal standard. After extraction with ethyl acetate and derivatization with diazomethane, the methylethers were detected by gas chromatography coupled with mass selective detection. The criteria of reliability were satisfactory. The imprecisions within the series and from day to day were in a range from 4.9 to 13.4%, and the detection limits were 1 microgram/L for PMA and 5 micrograms/L for p-TMA. The application of the method to urine samples of 32 subjects exposed to a median external concentration of 63 ppm toluene resulted in a median p-TMA excretion of 20 micrograms/L. However, no p-TMA was detected in the urine of subjects without occupational exposure to toluene. The determination of arylmercapturic acids is also suitable for biological monitoring of mixed exposures to toluene and benzene.

Acetylcysteine↗
PubMedDate not supplied

Determination of dialkyl phosphates in human urine using gas chromatography-mass spectrometry.

Organophosphates are used as pesticides in agriculture and pest control. They are metabolized to dialkylphosphates, which are excreted in urine. Determination of these metabolites is useful for assessing human exposure to organophosphates. This publication describes a new, reliable, and very sensitive analytical procedure for quantitating dimethylphosphate (DMP), diethylphosphate (DEP), O,O-dimethylthiophosphate (DMTP), O,O-diethylthiophosphate (DETP), O,O-dimethyldithiophosphate (DMDTP), and O,O-diethyldithiophosphate (DEDTP) in human urine. The analytes are extracted from acidified urine into a mixture of diethylether and acetonitrile. Dibutylphosphate serves as internal standard. Derivatization is performed using pentafluorobenzylbromide at 40 degrees C overnight. After further liquid-liquid extraction, analysis is carried out by gas chromatography-mass spectrometry. The limits of detection are 5 microg/L urine for DMP and 1 microg/L for the other five metabolites. Using the new procedure, 54 spot urine samples from persons in the general population in Germany were analyzed. Nearly every sample contained DMP, DEP, and DMTP, and the median values (95th percentiles) of the concentrations were 30 microg/L (105 microg/L), 4 microg/L (21 microg/L), and 22 microg/L (174 microg/L), respectively. DETP and DMDTP were found in lower concentrations.

Environmental Monitoring↗
PubMedDate not supplied

External quality assurance program for biological monitoring in occupational and environmental medicine.

Biological monitoring of chemical exposure in the workplace and in the environment has become increasingly important in assessing health risk. The analysis must be carried out under a quality assurance scheme to guarantee that the results obtained in biological monitoring are comparable with the threshold limit values and results from other laboratories. Since 1982, the German Society for Occupational and Environmental Medicine has offered 28 intercomparison programs. These programs cover 96 analytes in urine, blood, and plasma for 47 substances and cover most parameters that are relevant in occupational and environmental medicine. The data obtained in these programs provide a good overview of the current quality of the determination of analytes that are assessed in occupational and environmental toxicological laboratories. For the analyses of inorganic substances in blood and urine, the tolerable variation ranges from 7.5% to 43.5%. For organic substances in urine, the tolerable variation ranges from 12% to 48%. For organic substances in urine, the tolerable variation ranges from 12% to 48%. The highest variations (36% to 60%) were found for the analysis of organochlorine compounds in plasma. The tolerable variations for determining solvents in blood by head space gas chromatography range from 26% to 57%. The overall average success rates for the participants of the external quality programs range from 65% to 75%.

Environmental Monitoring↗