Determination of Trace Level Perchlorate in Seawater Using Dispersive Solid‑Phase Extraction and Co‑precipitation Extraction with Layered Double Hydroxides Followed by Ion Chromatography Analysis

摘要

In this manuscript, three-layered double hydroxides (LDH-CO_3~(2−), LDH-NO_3~−, and LDH-Cl~−) were synthesized and utilized as efficient sorbents for the extraction of perchlorate in water samples. Two different microextraction methods, namely dispersive solid-phase extraction (D-SPE) and co-precipitation extraction (Co-PE), were developed. Then performances of these methods were compared with previously reported in the literature. Analyses were performed using the ion chromatography (IC). The experimental conditions that affect the enrichment factor of the target analyte from the aqueous sample were investigated and optimized. The results showed (pH = 6) are the optimum for both methods. The Co-PE results demonstrated shorted extraction time (10 min) when compared to (20 min) D-SPE. After optimizing both methods, excellent linearity for the analyte in the range from 0.2 to 10 μg/L with coefficients of determination (r~2) from 0.992 to 0.997 is obtained. The limits of detection were calculated based on a signal-to-noise (S/N) ratio of 3: For Co-PE, it was 0.04 μg/L, and for D-SPE, it was 0.06 μg/L. The limits of quantitation were calculated based on S/N of 10 and were 0.12 and 0.19 μg/L, respectively. Methods percentage relative standard deviations (n = 3), 2 for Co-PE and 2.2% for D-SPE were obtained. The relative recoveries (mean ± standard deviation, n = 3) of perchlorate from 5 μg/L spiked real seawater samples for the two extraction techniques D-SPE and Co-PE were between (89.5 and 102.3 ± 2-6.1%) and (86 to 99.8 ± 1.7-5.8%), respectively. The two extraction methods, coupled with IC, were used to the determination of perchlorate concentration in seawater samples from the different locations in Saudi Arabia. Overall, the D-SPE process demonstrated better analytical capability when compared to Co-SPE and other reported methods.