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

Abstract

Lead is known as a toxic metal for human health and used in many industries. For instance, it is frequently used as a material for plumbing systems in drinking water cooler. Another typical materials containing lead is glaze which is a thin layer of liquid put on a piece of bowl or some ceremicware. Determination of lead amount leached from these samples is necessary and this could raise awareness of lead toxicity to consumers. Simple on-line spectrophotometric system for the determination of lead at trace level with on-line preconcentration step using Amberlite IR-120 as a sorbent packed in a minicolumn was developed. It is based on lead-4-(2-Pyridylazo)-resorcinol (PAR) complex formation 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. The enrichment factor of 47 was provided (at 4 min loading time). The column can be reused up to 84 cycles. The proposed method was successfully applied for detecting lead contamination in drinking water samples discharged from water coolers and leachates from glazed bowls with satisfactory recoveries within the range of 90-107%.