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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    International archives of occupational and environmental health 37 (1976), S. 47-55 
    ISSN: 1432-1246
    Keywords: Phenylglyoxylic acid ; Gaschromatography ; Diazomethane derivatization of phenylglyoxylic acid ; Styrene metabolites ; Urinalysis of styrene metabolites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The derivatization of phenylglyoxylic acid (PGA), a urinary styrene metabolite, gives with diazomethane under ordinary reaction conditions secondary products as expected from the behaviour of other α-keto acids. Thus reproducible quantitative analysis becomes difficult. It is shown that by proper selection of reaction conditions (low temperature, short reaction time) these secondary transformations can be inhibited and exclusive derivatization to the methylester is obtained. A quantitative determination of urinary PGA can be based on this derivatization procedure. However, this method is not considered suitable for routine monitoring due to the delicate reaction conditions necessary. The results are discussed with reference to a recently published procedure based on an unknown derivative of PGA.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    International archives of occupational and environmental health 44 (1979), S. 249-263 
    ISSN: 1432-1246
    Keywords: Styrene ; Human exposure ; Pharmacokinetics ; Mandelic acid ; Phenylglyoxylic acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To obtain the necessary information on the elimination kinetics of the main urinary metabolites in humans after styrene exposure (mandelic (MA) and phenylglyoxylic acids (PGA)), which is required in order to develop a biomonitoring program suitable for industrial exposure situations, human experimental exposures were carried out at concentrations of 50 to 200 ppm and durations of 4 to 8h, limiting the total exposure to 800 ppm.h (TWA at the TLV). MA analysis in urine was performed by silylation and gas chromatography. PGA was reduced to MA prior to analysis as previously described. The post exposure elimination of MA and PGA was found to follow biphasic kinetics, the elimination of PGA being slower than that of MA (MA: t 1/2 at 0-20 h = 3.9 h, at 30-60 h = 24.7 h; PGA: t 1/2 at 0-50 h = 10.5 h). The correlation of the urinary elimination of MA and PGA with exposure was studied at different post exposure times in order to select the sampling period suited best for biological exposure monitoring. The product balance of uptake and elimination confirmed that in contrast to the situation in animals, only an insignificant amount of styrene is metabolized to hippuric acid in humans. The discussion of the data obtained in this study with regard to the toxicity of styrene showed the need for epidemiological field studies using simultaneous air, biological, and medical monitoring. At present, such a study is being carried out in the polyester plastic industry.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    International archives of occupational and environmental health 37 (1976), S. 57-64 
    ISSN: 1432-1246
    Keywords: Mandelic acid ; Phenylglyoxylic acid ; Gaschromatography ; Styrene metabolites ; Urinalyses of styrene metabolites
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A simple and specific method for the quantitative gaschromatographic (GC) analysis of mandelic and phenylglyoxylic acid (MA and PGA), human urinary styrene metabolites, is described. MA is determined by trimethylsilylation and subsequent GC analysis. Because of difficulties involved in the direct determination of PGA due to the lack of quantitative and reproducible derivatization methods, this acid is reduced to MA prior to GC analysis. By a double determination with and without reduction both acids can be analyzed quantitatively. Both analysis show the same accuracy and precision and can therefore be intercorrelated accurately.
    Type of Medium: Electronic Resource
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