Determination of Trace Metals in Drinking Water Using Solid-Phase Extraction Disks and X-ray Fluorescence Spectrometry

Abstract

A convenient method is described for monitoring Cd, Ni, Cu, and Pb at trace levels in drinking water samples. These metals are preconcentrated on a chelating solid-phase extraction disk and then determined by X-ray fluorescence spectrometry. The method tolerates a wide pH range (pH 6-14) and a large amount of alkaline and alkaline earth elements. The preconcentration factor is well over 1600, assuming a 1 L water sample volume. The limits of detection for Cd, Ni, Cu, and Pb are 3.8, 0.6, 0.4, and 0.3 ng/mL, respectively. These are well below the federal maximum contaminant level values, which are 5, 100, 1300, and 15 ng/mL, respectively. The proposed method has many advantages including ease of operation, multielement capability, nondestructiveness, high sensitivity, and relative cost efficiency. The solid-phase extraction step can be conducted in the field and then the disks can be mailed to a laboratory for the analysis, eliminating the cost of transporting large volumes of water samples. Furthermore, the color of the used extraction disk provides an initial estimate of the degree of contamination for some transition metals (for example, Ni and Cu). Thus, the overall cost for analysis of metals in drinking water can be minimized by implementing the method, and small water supply companies with limited budgets will be better able to comply with the Safe Drinking Water Act.

Determination of Tellurium(IV) in Various Environmental Samples with Spectrophotometry

“…It is evident from the above data that the proposed method was simple, rapid and more sensitive than the reported methods in the literature as shown in Table 4. Less selective, high interference effect [9] Ethyl violet 560 1.55 ×10 4 Low sensitive and having less stability [10] Bismuthiaol II 330 3.64 ×10 4 Hg +2 , Se +4 , Fe 3+ and Sb 3+ interferes seriously [13] N-phenylbenzo hydroxamic acid 635 2.37 ×10 5 Needs elaborate process and benzene was used for extraction [14] NB/RB/BRB 580/ 565/ 565 3.33×10 6 / 1.76×10 6 / 1.88×10 6 Less stability, moderate interference effect [23] Leuco methylene green 650 4.2×10 4 Highly stable and selective, rapid, free from interference effect.…”

“…Tellurium enters into natural water through seepage from soils and industrial waste. Many analytical techniques such as Voltammetry 1 , Flame atomic absorption spectrometry 2 , Atomic absorption spectrometry 3,4 , Inductively coupled plasma-mass spectroscopy 5,7 , Inductively coupled plasma-atomic emission spectroscopy 8,9 , X-ray fluorescence 10,11 and Electrophoresis 12 have been employed for tellurium analysis in various environmental matrices. This increased the interest in developing rapid, sensitive and simple methods for the determination of traces of tellurium.…”

Determination of Heavy Metals at Sub-ppb Levels in Water by Graphite Furnace Atomic Absorption Spectrometry Using a Direct Introduction Technique after Preconcentration with an Iminodiacetate Extraction Disk

“…Table 3 compares the detection limits of the proposed method with those obtained by combining an IED with ICP-AES [12,13], ICP-MS [14], LIBS [15], or XRF spectrometry [17,18] for the determination of heavy metals in water. The detection limits of the proposed method are lower than those of LIBS and comparable to those of XRF spectrometry.…”

“…Several direct analysis methods combining an IED with Laser-Induced Breakdown Spectroscopy (LIBS) [15,16] or X-ray fluorescence (XRF) spectrometry [17,18] have been reported for the determination of heavy metals in water. Direct introduction/AAS [19] is also attractive.…”

Determination of Cr(III) and Cr(VI) in water by wavelength-dispersive X-ray fluorescence spectrometry after preconcentration with an ion-exchange resin disk

“…However, the above‐mentioned methods are complicated because they rely on a batch method. This problem can be solved by adopting a solid‐phase extraction disk/XRF spectrometry 8–10. Although Furusho et al 10 have recently reported a method for the determination of only Cr(VI) in tap water by WDXRF spectrometry with an anion‐exchange resin disk, an analytical method for the determination of Cr(III) and Cr(VI) by XRF spectrometry with a cation‐ and an anion‐exchange resin disk has not yet been developed.…”