A New Spectrophotometric Method to Determinate Lead (II) Ion in Vegetables with 2-[(6-Methoxy-2-benzothiazolyl) azo]-4-methoxy phenol as a New Reagent

A new, sensitive, and accurate spectrophotometric method for determining lead (II) ion in vegetables samples, using laboratory prepared reagent (6-MBTAMP) is developed. The reagent and pb+2 complex characterization included infrared spectroscopy, ultraviolet-visible spectrophotometry, elemental analysis (CHN), energy dispersive X-ray spectroscopy (EDX), and nuclear magnetic resonance spectroscopy (1HNMR & 13CNMR) techniques. The method depends on the reaction of lead (II) with the 6-MBTAMP reagent in a neutral medium to form a green-red complex which showed a maximum absorbance at 670 nm. The optimum conditions such as pH of the medium, reagent volume, reagent concentration, and time effect were also investigated carefully. Limit of detection (LOD), limit of quantification (LOQ) and Sandell’s sensitivity were calculated to be 0.181 mg L-1, 0.604 mg L-1 and 0.03 µg cm-2 respectively. The proposed method obeyed Beer’s law at range of 0.6-10 mg L-1 and the recovery percentage of the vegetable samples ranged from 71% to 106.6%. The suggested spectrophotometric technique is proved to be simple, fast and sensitive for determination of Pb (II) ion in vegetables samples.