Simple On-Line Preconcentration Spectrophotometry for Detecting Lead Contamination from Drinking Water Coolers and Glazed Bowl Samples

Lead is known as a toxic metal and can cause extensive damage for human health. Hence, the determination of lead is necessary and this could help raise public awareness of lead toxicity. A simple on-line spectrophotometric system for the determination of lead at a trace level with on-line preconcentration step using Amberlite IR-120 as a sorbent packed in a minicolumn was developed. It is based on Pb(II)-4-(2-Pyridylazo)-resorcinol (PAR) complex formation flowing along with ammonia buffer pH 10 to be detected spectrophotometrically at 519 nm. Under the optimal conditions, the linear range of 70-1000 μg l-1 with a correlation coefficient (R2) of 0.9998 was obtained. The limit of detection (LOD, based on 3Sx/y/m) of 55 μg l-1 and the relative standard deviation (RSD) within 5% (at 70 and 500 μg l-1, n = 10) were achieved with an enrichment factor of 47 at 4 min loading time. The column can be reused up to 84 cycles. The proposed method was successfully applied for detecting Pb(II) contamination in drinking water samples discharged from water coolers and leachates from glazed bowls with satisfactory recoveries within the range of 90-107%.