A new combined method of Rotative Liquid-Liquid Microextraction for preconcentration and determination of lead in urine samples by nanodrop- fiber optic-linear array detection spectrophotometry

A fast, ecological, and efficient method employing rotative liquid–liquid microextraction (RLLME) method for preconcentration and determination of lead in biological sampel such as urine was developed [1]. In this research combined method including Rotative liquid–liquid microextraction (RLLME) and nanodrop- fiber optic-linear array detection spectrophotometry (ND-FO-LADS) has been proposed. RLLME/ND-FO-LADS is based on the formation of a complex between the lead ions present in a sample and dithizone as the chelating agent and its microextraction into the organic solvent [2]. The remained phase after RLLME was introduced as a single drop into the nanodrop traycell of fiber optic spectrophotometer. The nanodrop spectrophotometric method can be used to avoid the use of large volumes of reagent solution, and typically requires only a single drop of sample solution to take spectrophotometric measurements [3]. The optimum microextraction conditions for 5 mL water sample were: extraction solvent, chloroform; volume of extracting, 100 μL; Rotation time, 50 s; Under the optimum conditions, the calibration curve was linear in the range of 20-80 ng mL–1 and detection limit was 3.5 ng mL–1. The relative standard deviation was 5.33. The validated method was applied for preconcentration and determination of lead in urine samples. The average recoveries of urine samples were 94%. The proposed combined method is simple, rapid, sensitive and environmentally friendly for determining traces of lead in the urine samples.