A new portable switchable hydrophilicity microextraction method for determination of vanadium in microsampling micropipette tip syringe system couple with ETAAS.

First time we launch an innovative and simple portable in a closed micropipette tip switchable hydrophilicity microextraction syringe system (µS-SHS) couple with electrothermal atomic absorption spectroscopy (ETAAS) was developed for preconcentration and determination of vanadium using 2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol (5- Br-PADAP), as complexing. In the proposed method decanoic acid was used as a switchable hydrophilicity extraction solvent and their polarity was switched on and off (water miscible/immiscible) by simply changing their pH. The phase separation was induced by simply adding sulfuric acid that switch off hydrophilicity (nondispersed/immiscible) of decanoic acid. The metal complex enriched phase (V-(5-Br-PADAP-SHS) was separated by simply removing the aqueous phase through manually dispensed syringe system. Then finally acidic ethanol drawn into the syringe contains metal complex enriched SHS phase to reduce viscosity and directly injected into the ETAAS by using an enclosed micropipette tip syringe system. The multivariate strategy was applied to screen out and optimized the variables. Limit of detection (LOD), enhancement factor (EF) and relative standard deviation (RSD) were found 0.0075 µg L-1, 120 and 2.91%, respectively. Certified reference material of riverine water (SLRS-4), Apple leaves (NIST SRM 1515) and a standard addition method was used to validate the present method. Developed method was applied to water and food samples. We successfully applied the proposed method to analyze vanadium in different real food and water samples.