Study of the correlation between blood cholinesterases activity, urinary dialkyl phosphates, and the frequency of micronucleated polychromatic erythrocytes in rats exposed to disulfoton

Organophosphates (OPs) are widely used as pesticides, and its urinary metabolites as well as the blood cholinesterases (ChEs) activity have been reported as possible biomarkers for the assessment of this pesticide exposure. Moreover, the OPs can induce mutagenesis, and the bone marrow micronucleus test is an efficient way to assess this chromosomal damage. This paper reports a study carried out to verify the correlation among the disulfoton exposure, blood ChEs activity, urinary diethyl thiophosphate (DETP), and diethyl dithiophosphate (DEDTP), as well as micronucleated polychromatic erythrocytes (MNPCEs) frequency. Four groups of rats (n=12) were exposed to disulfoton at 0, 2.8, 4.7, and 6.6 mg kg-1 body weight. The blood ChEs activity, urinary DETP and DEDTP concentrations, and MNPCEs frequency were determined. It was observed that the plasmatic and erythrocytary ChEs activity decreased from 2.9% to 0.5% and from 35.9 to 3.3%, respectively, when the disulfoton dose was increased from 0 to 6.6 mg kg-1 (correlation of 0.99). Urinary DETP and DEDTP concentrations, as well as the MNPCEs frequency, increased from 0 to 6.58 µg mL-1, from 0 to 0.04 µg mL-1, and from 0 to 1.4%, respectively, when the disulfoton dose was increased from 0 to 6.58 mg kg-1 body weight.

Os organofosforados (OPs) são amplamente usados como praguicidas e a atividade da colinesterase sanguínea bem como os metabólitos urinários desses praguicidas têm sido reportados como biomarcadores eficazes para avaliar casos de exposição. Além disso, os OPs podem induzir mutagênese e o teste de micronúcleo de medula óssea é uma boa alternativa para avaliar os danos cromossômicos. Esse artigo reporta um estudo sobre a correlação entre a exposição a dissulfoton, a atividade da colinesterase sanguínea, a excreção urinária de dietil tiofosfato e dietil ditiofosfato e a frequência de micronúcleos em eritrócitos policromáticos. Quatro grupos de ratos (n=12) foram expostos a dissulfotom nas doses de 0, 2,8, 4,7, e 6,6 mg kg-1 de peso corpóreo. A atividade da colinesterase sanguínea as concentrações urinárias de dietil tiofosfato e dietil ditiofosfato e a frequência de micronúcleos foram determinadas. Os resultados demonstraram que as atividades da colinesterase plasmática e eritrocitária diminuíram de 2,9 para 0,5% e de 35,9 para 3,3% , respectivamente, quando a dose de dissulfoton foi aumentada de 0 para 6,6 mg kg-1 (correlação de 0,99). As concentrações urinárias de dietil tiofosfato e dietil ditiofosfato bem como a frequência de micronúcleos aumentaram de 0 a 6,56 µg mL-1, 0 a 0.04 µg mL-1 e de 0 a 1.4%, respectivamente, quando a dose de dissulfotom foi aumentada de 0 a 6,58 mg kg-1.

Molecularly imprinted solid phase extraction of urinary diethyl thiophosphate and diethyl dithiophosphate and their analysis by gas chromatography-mass spectrometry.

An analytical method involving molecularly imprinted solid phase extraction (MISPE) and gas chromatography-mass spectrometry (GC-MS) was developed for the analysis of organophosphates metabolites (diethyl thiophosphate--DETP and diethyl dithiophosphate - DEDTP) in human urine samples. A DETP molecularly imprinted polymer (MIP) was synthesized using 4-vinylpiridine as the functional monomer and ethylene glycol dimethacrylate as the cross-linker. The conditioning step of the MISPE was conducted by running 3 mL of acetonitrile, 3 mL of 0.1 mol L⁻¹ dibasic phosphate buffer at pH 11 and 2 mL of water through the molecularly imprinted polymer (MIP) cartridge. The extraction step was executed using 1.0 mL of a urine sample, with the pH previously adjusted to 3.0. Finally, the analytes were eluted with 3 mL of acetonitrile and derivatized with 3% 2,3,4,5,6-pentafluorobenzyl bromide solution at room temperature for 1h. The sample was analyzed by GC-MS in the SIM (selected ion monitoring) mode. Analytical calibration curves for DETP and DEDTP were constructed using a pool of urine samples and six levels of concentration. The method was found to be linear from 10 to 500 µg L⁻¹ (r>0.99) with limits of quantification of 10 µg L⁻¹ for both analytes. The within-day and between-day precisions were evaluated (as %RSD) and all the results were <15% for both analytes. The method was accurate (relative error<±15%), with good robustness.

Application of molecularly imprinted polymer solid-phase extraction for salivary cotinine.

A method constituted by molecularly imprinted solid-phase extraction (MISPE) with high-performance liquid chromatography coupled to diode array detector (HPLC-DAD) was developed for cotinine analysis in saliva samples. For this purpose, the separation was carried out with a C18 reversed-phase column at 20 °C. The mobile phase which was composed of a mixture of 09:91 (v/v) acetonitrile/phosphate buffer, pH 6.3, was delivered with isocratic flow rate at 1.4 mL min(-1). Employing MISPE, the best conditions were achieved with 1.5 mL of saliva plus 1.5 mL of 0.1 mol L(-1) of acetate buffer, pH 5.5, which were then passed through a cartridge previously conditioned with 2 mL acetonitrile, 2 mL methanol, and 2 mL of 0.1 mol L(-1) sodium acetate buffer, pH 5.5. The washing was carried out with 1 mL deionized water, 1 mL of 0.1 mol L(-1) sodium hydroxide, and 1 mL hexane; finally; the cotinine elution was carried out with 3 mL methanol/water (97.5: 2.5, v/v). Linearity ranged from 30 to 500 ng mL(-1) with r > 0.99. Intra-assay, interassay precision, and accuracy ranged from 3.1% to 10.1%, 5.2% to 15.9%, and 99.22% to 111.17%, respectively. The detection and quantification limits were 10 and 30 ng mL(-1), respectively. This investigation has provided a reliable method for routine cotinine determination in saliva, and it is an important tool for monitoring cigarette smoke exposure in smokers. The method was applied in five smokers' samples who consumed around five to 20 cigarettes per day and the values of cotinine in saliva were from 66.7 to 316.16 ng mL(-1).

Simultaneous detection of three antineoplastic drugs on gloves by liquid chromatography with diode array detector

The aim of this study was to develop a method for simultaneous detection of antineoplastic drugs on gloves since, in occupational exposure, the main contamination route is through dermal contact, which may occur via prolonged contact with contaminated surfaces or materials. The assay was performed by liquid chromatography using the following conditions for the detection of 5-fluorouracil (5-FU), methotrexate (MTX) and paclitaxel (TAX): diode array detection and UV quantification at 195 nm for TAX, at 265 nm for 5-FU and at 302 nm for MTX; ODS column (250 x 4 mm, 5 μm) with a similar guard column; mobile phase consisted of water (pH 4)-methanol-acetonitrile (35:15:50, v/v/v) with a flow rate of 1 mL min-1. The method presented a linear range from 0.25 to 20 μg mL-1 with r² higher than 0.99. Repeatability was <15% and satisfactory extraction efficiency was obtained when liquid-liquid extraction with ethyl acetate was used for 5-FU and TAX. Satisfactory solid phase extraction was also achieved with C18 cartridges and elution with methanol for MTX. The diode array detector allowed drug quantification at a concentration > 0.25 μg mL-1 in samples, although detection was possible in samples that presented values of around 0.1 μg mL-1. The results obtained suggest that the method developed can be applied for the simultaneous determination of the drugs studied and can be considered useful in exposure assessment for health care workers.

O objetivo deste estudo foi desenvolver um método para a detecção simultânea de antineoplásicos em luvas, uma vez que, em exposições ocupacionais, a principal via de introdução é a dérmica, por meio de contato prolongado com superfícies e/ou materiais contaminados com tais fármacos. A tecnica de detecção utilizada foi a cromatografia líquida de alta eficiência, com detector de aranjo de diodos, nas seguintes condições: para a detecção de 5-fluorouracila (5-FU), metotrexato (MTX) e paclitaxel (TAX): detecção e quantificação de TAX a 195 nm, de 5-FU a 265 nm e de MTX a 302 nm; coluna ODS (250 x 4 mm, 5 μm), com pré-coluna similar; fase móvel constituída de água (pH 4)-metanol-acetonitrila (35:15:50, v/v/v), na vazão de 1 mL min-1. O método apresentou uma faixa linear de 0,25-20 mg mL-1, com r² > 0,99. O desvio-padrão relativo, para a avaliação da repetibilidade foi < 15%; a recuperação foi satisfatória, empregando extração líquido-líquido, com acetato de etila, para a 5-FU e TAX e extração em fase sólida, com cartuchos de C18 e eluição com metanol, para MTX. O detector de arranjo de diodos permitiu a quantificação dos fármacos, quando presentes nas amostras em concentração > 0,25 mg mL-1, embora a detecção foi possível nas amostras que apresentaram valores em torno de 0,1 mg mL-1. Os resultados obtidos sugerem que o método desenvolvido pode ser aplicado para a determinação simultânea dos fármacos estudados, constituindo ferramenta útil na avaliação da exposição dos trabalhadores as fármacos antineoplásicos.