Urine samples human exposure application

For applications in the diagnostics and biomarker area, 8-oxo-7,8-dihydro-2,-deoxyguanosine (8-oxoGuo) was measured as an oxidation stress biomarker in urine samples from smokers and non-smokers (Hu et al. 2006). When 100, uL of samples (10 times dilution) were used, a detection limit of 5.7 pg/mL (2.0 fmol) was achieved. The cycle time was 10 min per sample. The application was used for clinical scale. A similar approach was used for the detection of N7-methylguanine, another carcinogen exposure biomarker in human urine (Chao et al. 2005). 

No studies were located regarding the metabolism of 3,3 -dichlorobenzidine in humans following dermal exposure. In a 24-hour urine sample of rats given a single dermal application of 3,3 -dichlorobenzidine (50 mg/kg/day), -diacetyl 3,3 -dichlorobenzidine (but not/V-acetyl 3,3 -dichlorobenzidine or the unchanged chemical) was detected (Tanaka 1981). Since the mutagenicity of diacetylated product is much less than either the monoacetylated or parent compoimd (Lazear et al. 1979 Reid et al. 1984 ... 

The long term objective of our work is to examine the applications of LC-MS in measuring human exposure to toxic substances. Specifically, we are investigating the direct measurement of polar and ionic metabolites of toxic compounds in the urine. Common mammalian metabolic routes include conjugation with glucuronide or sulfate moieties (9), and such conjugates are difficult to analyze by GC without extensive sample preparation (10, H). The model compounds chosen for this study and their typical parent compounds are shown in Table I. 

The accuracy of determinations of picloram in fortified river water and human urine samples determined by the RIA was good with the mean overall amounts detected varying from 82% to 110% of the amount of picloram added (Table I). The range of concentrations over which picloram was accurately quantitated with no sample clean-up correspond with levels found in urine in applicator exposure studies conducted by Libich et al. (19). It must be emphasized that determination of unknown concentrations of picloram in river water and urine was performed by using standard curves prepared in the respective matrix. 

Application to Human Exposure (Urine Samples). Vycudihk (1985, 1987) analyzed urine samples from multiple casualties of the Iran-Iraq War in the 1980s that were hospitalized for treatment of suspected sulfur mustard exposure. Urine samples from eight of the patients produced positive results for sulfur mustard using GC-MS. Concentrations found ranged from 1 to 30 ng/mL. The method could not distinguish between sulfur mustard and its hydroxyethyl metabohtes that were present in the urine samples. 

Application to Human Exposure (Urine and Blood). To date, there have been no reports of the collection of biomedical samples from individuals with suspected lewisite exposure. Samples from such an incident will be critical for confirming the validity of assaying for the biomarkers observed in animal models. Additionally, the biomarkers that have been investigated in animal studies to date have indicated a rapid clearance in urine and less so for blood. This will obviously create severe problems for the retrospective determination of lewisite exposure beyond a few days at most when analyzing urine samples. The blood assay for both bound and free CVAA will potentially provide a longer opportunity for retrospective confirmation of exposure (based on one animal study), but also indicates a substantial decrease (90%) in concentration levels observed over a 10 day period. 

As with urine, saliva (spumm) is easy to collect. The levels of protein and lipids in saliva or spumm are low (compared to blood samples). These matrices are viscous, which is why extraction efficiency of xenobioties amoimts to only 5 to 9%. By acidifying the samples, extraction efficiencies are improved as the samples are clarified, and proteinaceous material and cellular debris are precipitated and removed. Some xenobioties and their metabohtes are expressed in hair. Hair is an ideal matrix for extraction of analytes to nonpolar phases, especially when the parent xenobioties are extensively metabolized and often nondetectable in other tissues (parent molecules of xenobioties are usually less polar than metabolites). Hair is a popular target for forensic purposes and to monitor drug compliance and abuse. Human milk may be an indicator of exposure of a newborn to compounds to which the mother has been previously exposed. The main components of human milk are water (88%), proteins (3%), lipids (3%), and carbohydrates in the form of lactose (6%). At present, increasing attention is devoted to the determination of xenobioties in breath. This matrix, however, contains only volatile substances, whose analysis is not related to PLC applications. 

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