HG-ICP-OES technique, a useful tool for arsenic determination in soft water

Abstract

This paper presents a fast, sensitive, linear and precise method for the determination of arsenic (As) at trace levels, from different types of water (drinking, mineral, surface water and groundwater) using hydride generation and optical emission spectrometry with inductively coupled plasma (HG-ICP-OES). In order to generate the hydride, the initial pretreatment of the samples with a mixture of potassium iodide and ascorbic acid is necessary, in hydrochloric acid medium for reducing the As5+ to As3+ ions and for the subsequent formation of the hydride from As3+ ions and sodium borohydride, in a continuous-flow cell. The quantification limit of the method (LOQ = 0.43 µg/L), the precision (3.41%), the recovery yield (95%) and the measurement uncertainty of 24% frame the method within the limits imposed by the acceptance criteria of an analytical method for arsenic determination. The proposed method was tested on several types of water, the obtained results being compared to those obtained by applying two sensitive and selective alternative methods using ICP-MS, respectively ultrasonic nebulizer and ICP-OES.