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2749617 
Journal Article 
Determination of Butylated Hydroxytoluene in Plasma by High-Performance Liquid Chromatography 
Verhagen, H; Thijssen, HHW; Kleinjans, JCS 
1987 
1 
Journal of Chromatography
ISSN: 0021-9673 
NIOSH/00175827 
422 
C 
288-293 
English 
3437016 
WOS:A1987L157200032 
A chromatographic method for determining butylated-hydroxytoluene (128370) (BHT) in plasma was described. Samples were diluted to 1.0 milliliter (ml) with water. A 25 microliter (microl) aliquot of 100 micrograms per ml (microg/ml) 3,5-di-tert-butyl-4-hydroxyanisole (DBHA) was added as an internal standard. The samples were extracted with 5ml of corn oil enriched diethyl-ether (ether). The organic phase was separated and evaporated to dryness at 0 degrees-C. The residue was dissolved in 0.5ml methanol to which 0.5ml hydrochloric-acid was added. The mixture was heated at 95 degrees for 1 hour to dealkylate BHT and DBHA to their highly fluorescent counterparts 3-mono-tert-butyl-4-hydroxytoluene and 3-tert-butyl-4-hydroxyanisole (25013165), respectively. The samples were cooled, extracted with ether and evaporated to dryness as before. The residue was reconstituted in 500microl of a 45:54:1 mixture of acetonitrile/water/acetic-acid and analyzed by reversed phase high performance liquid chromatography with isocratic elution and fluorescence detection. When samples spiked with 50, 500 and 5000 nanograms per ml (ng/ml) BHT were analyzed by the method, BHT concentrations of 51, 460 and 5106ng/ml, respectively, were measured. The corresponding coefficients of variation were 7, 2 and 4 percent. Male Wistar-rats were dosed orally with 200mg/kg BHT. Blood samples were collected at various times for up to 480 minutes after dosing and analyzed. A maximum blood BHT concentration of around 3microg/ml occurred after 2 to 3 hours. The authors note that similar experiments with butylated hydroxyanisole (25013165) (BHA) showed maximum BHA concentrations of 0.2 to 1.0microg/ml. They conclude that compared with BHA, BHT is absorbed more rapidly from the gastrointestinal tract or cleared more slowly from the plasma