Urine analysis for 3,5,6-TCP and creatinine

The urine samples were analyzed using a modified version of a published method.8 The method involved fortification of the urine samples with an internal standard 3,4,5-trichloro-2-pyridinyl, which is a structural isomer of the 3,5,6-TCP metabolite of chlorpyrifos hydrolysis of labile acid conjugates to 3,5,6-TCP solvent extraction derivitization to the f-butyl-dimethylsilyl ester of 3,5,6-TCP and subsequent negative-ion chemical ionization gas chromatography/mass spectrometry (GC/MS) analysis. Creatinine was determined in urine using a modification of a method of Fabiny and Erting-shausen.9 

Calculations of total respiratory and dermal exposure as well as calculation of chlorpyrifos body burden from urine data 

Total dermal exposure (TDE) was calculated using the following steps  

Determine the amount of chlorpyrifos on the outside torso section of the coverall and the t-shirt and briefs sample. 

Determine the percent penetration of chlorpyrifos through the outer layer of the torso section of the coverall (micrograms chlorpyrifos on t-shirt and briefs)/(micrograms chlorpyrifos on torso section). 

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