Application of response surface methodology for optimization and determination of nickel by syringe to syringe dispersive liquid phase micro-extraction in environmental water and herb samples coupled with flame atomic absorption spectrometry

A novel, rapid, simple and sensitive syringetosyringedispersive liquid–phase microextraction (SSDLPME) method followed by flame atomic absorption spectrometry was proposed for preconcentration and determination of nickel ion in water and herbal samples using 1(2pyridylazo)2naphthol as a chelating agent. Various experimental factors on preconcentration and determination of nickel such as pH of sample solution, concentration of the complex agent, volume of the extraction solvent, shooting times, centrifugation time and ionic strength were investigated using Plackett–Burman design for screening and BoxBehnken design as an optimization method. Under optimum conditions, the calibration curve was linear over the range of 10 875 µg L1 with the coefficient of determination R2 = 0.997 and the detection limit of 1.800 µg L1. Relative standard deviation (R.S.D) for 8 replicate determinations and the enrichment factor (EF), were 2.050% and 86, respectively. Finally, the proposed method was applied successfully to preconcentration and determination of the analyte in environmental water and herbal samples