RESUMEN
By proper design of an innovative extraction device, a lab-made multipurpose autosampler was exploited in the automated performance of the dynamic large drops based microextraction. The pluses of this new analytical strategy were demonstrated in the determination of sulfonamides and fluoroquinolones in surface water samples, by direct immersion single drop microextraction (SDME) and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analysis. Operational autosampler features and critical experimental factors influencing SDME, including the extraction mode (static or dynamic), extraction, stirring rate, salt addition, drop size, number of cycles and drop exposition time, were comprehensively investigated using both univariate and multivariate optimization. The lab-made autosampler allowed to performance challenging dynamic and static large drop based SDMEs in an automated and effortless way and with minimal requirements of hardware and software. Large stable drops provided high surface area, enhancing the phase ratio and in consequence increasing the analytes uptake. The best extraction efficiencies were obtained as a result of the synergic interaction between the use of large drops and the automated dynamic mode of extraction. The developed method proved to be a reliable, sensitive, and robust analytical tool, with intraday RSDs ranging between 4.0 and 7.6% (nâ¯=â¯6), and interday RSDs between 4.8 and 9.3% (nâ¯=â¯6), and, LOD and LOQ in the range of 15-50 and 35-100â¯ngâ¯L-1, respectively.
Asunto(s)
Antibacterianos/aislamiento & purificación , Fluoroquinolonas/aislamiento & purificación , Microextracción en Fase Líquida/métodos , Robótica/métodos , Sulfonamidas/aislamiento & purificación , Contaminantes del Agua/aislamiento & purificación , Antibacterianos/análisis , Cromatografía Liquida , Fluoroquinolonas/análisis , Microextracción en Fase Líquida/instrumentación , Robótica/instrumentación , Sulfonamidas/análisis , Espectrometría de Masas en Tándem , Contaminantes del Agua/análisisRESUMEN
A high-throughput and innovative setup has been developed to automate the online integration of single drop microextraction (SDME), liquid chromatography (LC) and high-resolution mass spectrometry (QqToF). SDME and LC were online hyphenated for the first time. SDME was carried out by a lab-made cartesian robot actuating a 100 µL syringe, equipped with a three-way solenoid microvalve that allowed the online transference of the enriched extract to the chromatographic system, through a six-port switching valve. The complete method, including the synchronized robot action, valves, and the analytical instruments, was controlled by an Arduino Mega board. The merits of the proposed setup were demonstrated by the triazines determination in coconut water samples. The most relevant extraction parameters, such as drop size, exposure time, stirring effect, salt addition and pH were systematically investigated. Under optimized conditions (60 µL drop volume and 10 min extraction time), the LC-UV enrichment factors (EF) and the extraction recoveries (ER) ranged between 15.2-18.4 and 11.4-13.8%, respectively. Using the SDME-LC-MS setup, the linear range, detection limit (S/N = 3) and precision (RSD, n = 6 at 0.25 µg L-1 level of concentration) were 0.25-25 µg L-1, 0.10 µg L-1 and 16.8% for simazine; 0.25-25 µg L-1, 0.05 µg L-1 and 14.7% for atrazine; and 0.25-25 µg L-1, 0.05 µg L-1 and 18.5% for propazine, respectively. Although none of the analytes were detected in the evaluated commercial samples, the results indicate that the proposed online SDME-LC setup is a competitive analytical strategy for the determination of target organic compounds in complex matrices.