US EPA

2799294 

Journal Article 

Urinary Dimethylbenzoic Acid Excretion As An Indicator Of Occupational Exposure To White Spirit 

Pfaffli, P; Harkonen, H; Savolainen, H 

1985 

1 

Journal of Chromatography
ISSN: 0021-9673 

NIOSH/00146495 

337 

1 

146-150 

English 

3980645 

WOS:A1985ACG9300021 

A liquid chromatographic method was developed for quantitating occupational exposure to white-spirit (8030306) vapors. Ten car washers occupationally exposed to white-spirit vapors were divided into three groups: five workers exposed to between 118 and 150 milligrams per cubic meter (mg/m3), three workers exposed to between 152 and 234mg/m3 and two workers exposed to between 420 and 500mg/m3, calculated as a 6 hour time weighted average concentration in the breathing zones of workers. Workers not exposed to white-spirit vapors served as comparisons. Urine samples were obtained and hydrolyzed with 50 percent sodium-hydroxide. Hydrolysates were neutralized and extracted with dichloromethane and dried with sodium-sulfate under vacuum. The residue was dissolved in acetic-acid, methanol, and water mixture and subjected to chromatography. A liquid chromatographic analyzer with an ultraviolet detector at a wavelength of 238 nanometers was used for separating the white-spirit metabolite dimethylbenzoic-acid (30587190) isomers. The procedure yielded good separation of 2,3-dimethylbenzoic-acid (603792), 3,5-dimethylbenzoic-acid (499069), while other isomers migrated together as one peak. The recovery of added standard isomers by this method was about 95 percent. No dimethylbenzoic-acid isomers were detected in the urine samples of comparisons. The mean urinary excretion rates of isomers were linearly correlated with the total exposure to white-spirit vapors. The authors conclude that the urine test relates well to individual exposure to white-spirit.