RESUMEN
Diazinon poisoning is an important issue in occupational, clinical, and forensic toxicology. While sensitive and specific enough to analyse diazinon in biological samples, current methods are time-consuming and too expensive for routine analysis. The aim of this study was therefore to design and validate a simple dispersive liquid-liquid microextraction (DLLME) for the preparation of urine samples to be analysed for diazinon with high performance liquid chromatography with diode-array detector (HPLC-DAD) to establish diazinon exposure and poisoning. To do that, we first identified critical parameters (type and volume of extraction and disperser solvents, pH, surfactant, and salt concentrations) in preliminary experiments and then used central composite design to determine the best experimental conditions for DLLME-HPLC-DAD. For DLLME they were 800 µL of methanol (disperser solvent) and 310 µL of toluene (extraction solvent) injected to the urine sample rapidly via a syringe. The sample was injected into a HPLC-DAD (C18 column, 250×4.6 mm, 5 µm), and the mobile phase was a mixture of acetonitrile and buffer (63:37 v/v, pH 3.2; flow rate: 1 mL/ min). Standard calibration curves for diazinon were linear with the concentration range of 0.5-4 µg/mL, yielding a regression equation Y=0.254X+0.006 with a correlation coefficient of 0.993. The limit of detection and limit of quantification for diazinon were 0.15 µg/mL and 0.45 µg/mL, respectively. The proposed method was accurate, precise, sensitive, and linear over a wide range of diazinon concentrations in urine samples. This method can be employed for diazinon analysis in routine clinical and forensic toxicology settings.
Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Cromatografía Líquida de Alta Presión/normas , Diazinón/toxicidad , Diazinón/orina , Insecticidas/toxicidad , Insecticidas/orina , Microextracción en Fase Líquida/métodos , Microextracción en Fase Líquida/normas , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Reproducibilidad de los ResultadosRESUMEN
A novel approach for dispersive liquid-liquid microextraction based on the use of deep eutectic solvent as a disperser was presented for the first time. The procedure was automated based on an in-syringe flow system coupled with UV-Vis detection and demonstrated by the determination of chromium (VI) in beverages. This analytical task was used as a proof-of-concept example. The automated extraction procedure involved the aspiration of aqueous sample into a syringe pump with homogeneous mixture of extraction solvent (1-oÑtanol) and deep eutectic solvent (tetrabutylammonium bromide - formic acid) containing color-forming reagent (1,5-diphenylcarbazide). This led to decomposition of deep eutectic solvent in aqueous phase resulting in dispersion of extraction solvent, oxidation of 1,5-diphenylcarbazide to 1,5- diphenylcarbazone in the presence of chromium (VI), and formation of colored chromium (III) complex with 1,5-diphenylcarbazone and its fast extraction. In this case composition of deep eutectic solvent played a key role for analyte extraction. Tetrabutylammonium bromide promoted mass transfer between aqueous phase and the extraction solvent droplets as a salting out agent, bromide ion acted as an ion-pare agent for analyte complex extraction, formic acid provided required pH value for analyte complex formation. Under the optimal conditions the limit of detection, calculated from a blank test based on 3s, was 0.2⯵gâ¯L-1. The automated dispersive liquid-liquid microextraction using deep eutectic solvent as disperser can be considered as an available, efficient, rapid and environmentally friendly sample pretreatment approach.