ABSTRACT
Occupational exposure to volatile organic compounds (VOC) might generate serious worker health damages. Therefore, biological monitoring is essential to evaluate exposure biomarkers from highly toxic chemicals, ensuring better attention to the worker health. In this study was developed and validated a bioanalytical method based on high-performance liquid chromatography coupled to photodiode array (HPLC-PDA) for the quantification of VOC biomarkers in urine samples from Federal University of Goias (UFG) workers. Samples were collected from 30 occupationally exposed subjects after application of a questionnaire survey. The following biomarkers hippuric acid, methyl-hippuric acid, mandelic acid, phenylglyoxylic acid and phenol were quantified, representing exposition to toluene, xylene, styrene, ethylbenzene, benzene and phenol solvents, respectively. Hippuric acid levels were found close to or above the reference values, although a subject had levels higher than preconized by Biological Limit Values (BLV) guideline of 4.0 mg/g creatinine. Five subjects had 3 and 4-methylhippuric acid ranging from 0.1 to 1.0 mg/g creatinine. These results indicate a moderate to high VOC exposure from UFG workers. Multivariate analysis generated four clusters and indicated that histotechnicians and graphic workers need especial attention on occupational VOC exposure. The results from this study reinforce the need for reliable methods able to the biological monitoring as an important tool for assessing occupational exposure.
Subject(s)
Occupational Exposure , Volatile Organic Compounds , Brazil , Environmental Monitoring , Humans , Occupational Exposure/analysis , Toluene , Universities , XylenesABSTRACT
Cotinine is the major metabolite of nicotine and, being very stable and having a long biological half-life, it can be used as a biomarker for tobacco exposure. The aim of this study was to develop an analytical GC-MS technique to measure levels of cotinine in the urine of active and passive smokers and to compare the results with reference values. The extraction of cotinine to generate the calibration curve was performed by mixing urine (250 ?L) with 50 ?L of a cotinine standard, 50 ?L of an internal standard of deuterated cotinine (15μgμmL-1) and 50 μL of 10% NH4OH solution. Next, 2 mL of a mixture of MTBE:dichloromethane:ethyl acetate (30:30:40 by volume) was added and the whole was vortexed, then centrifuged at 3000 rpm. Finally, 1.6 mL of the organic layer was evaporated under a stream of dry air at 50 °C. The resulting extract was dissolved in methanol and injected into the GC-MS system. The LOQ and LOD for cotinine were 100 and 20 ng.mL-1, respectively. The curve was linear over the whole tested range of 100 - 5000 ng.mL-1 and the method achieved 50% recovery. The intra and inter-day precisions were 1.62 ? 7.28% and 0.86 - 2.68%, respectively. Accuracy was determined at three concentrations (low, medium and high), with six replicates (95.24- 97.67%). The validation of this cotinine assay by GC-MS showed that it exhibited satisfactory limits and the assay could be performed with a one-step liquid-liquid extraction. The technique presented here can thus be used for the quantitation of cotinine levels in the urine of passive and active smokers.
A cotinina é o metabólito principal da nicotina, é muito estável e tem uma elevada meia-vida biológica e pode ser usado como biomarcador da exposição ao tabaco. O objetivo deste estudo foi desenvolver uma técnica analítica em CG-EM para medir os níveis de cotinina na urina de fumantes ativos e passivos e comparar os resultados com valores de referência. A extração da cotinina para construir a curva de calibração foi desenvolvida misturando 250 μL de padrão de cotinina em urina, 50 μL de padrão interno (cotinina deuterada 15 ?g?mL-1) e 50 μL de solução aquosa de NH4OH 10%. Em seguida, 2 mL da mistura MTBE:diclorometano:acetato de etila (30:30:40 v/v) foi adicionada, agitada em vórtex e centrifugada a 3000 rpm. Finalmente, 1,6 mL da camada orgânica foi evaporada sob ar seco a 50 °C. O extrato resultante foi dissolvido em metanol e injetado no sistema CG-EM. Os limites de quantificação e de detecção foram 100 e 20 ng?mL-1, respectivamente. A curva de calibração foi linear no intervalo de concentração testado (100 - 5000 ng?mL-1), com 50% de recuperação. Os valores de precisão intra-dia e inter-dia foram 1,62 ? 7,28% e 0,86 - 2,68%, respectivamente. A exatidão (95,24 - 97,67%) foi determinada sob 3 concentrações (baixa, média e alta), com 6 replicatas. A validação deste procedimento para análise de cotinina por CG-EM demonstrou valores satisfatórios, numa única etapa de extração líquido-líquido, podendo ser utilizada para a quantificação dos níveis de cotinina em amostras de urina de fumantes ativos e passivos.
