A simple and rapid method for simultaneous pre-concentration of eight trace-heavy-metals in water using 1-(2-pyridylazo)-2-naphthol and yttrium for X-ray fluorescence spectrometry

Abstract

A simple and rapid pre-concentration technique was proposed for the simultaneous determination of eight trace heavy metals in water by energy-dispersive X-ray fluorescence (EDXRF) spectrometry. Yttrium was added as a carrier ion to a sample solution containing Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn. The metals were collected on a membrane filter as precipitates or co-precipitates with 1-(2-pyridylazo)-2-naphthol at pH 10. The metals on the filter were determined by EDXRF spectrometry. Yttrium improved the collection efficiency of Cr(III) drastically and also expanded the pH ranges for quantitative recoveries of the metals. Only fifteen minutes was required to prepare the membrane filter retaining the metals. Linear calibrations were obtained from mg L À1 to mg L À1 levels of the metals in 50 mL sample solution. The limits of detection were as follows: Cd, 1 mg L À1 ; Cr, 0.3 mg L À1 ; Cu, 1 mg L À1 ; Fe, 1 mg L À1 ; Mn, 0.3 mg L À1 ;Ni, 2 mg L À1 ; Pb, 2 mg L À1 ; and Zn, 2 mg L À1 . The sensitivities were sufficient for monitoring drinking water. The proposed method was applied to river water and underground water samples. The analytical results agreed with those obtained by GF-AAS for the detected metals. The recoveries of the spiked metals in the water samples were quantitative. This method was extended to the separation and determination of Cr(III) and Cr(VI). The proposed system of pre-concentration and EDXRF spectrometry has high potential for routine monitoring of trace heavy metals because of its simplicity and rapidity besides cost-effectiveness.

Rapid Determination of Sub-ppm Heavy Metals in the Solution State via Portable X-ray Fluorescence Spectrometry Based on Homogeneous Liquid-Liquid Extraction in a Ternary Component System

“…In this study, we adopted HoLLE in the water-ethanoldimethyl phthalate ternary component system owing to environmental reasons and on-site workability. Regarding XRF for heavy metals, the sorbent method, 22 the ion exchange membrane method, 23 the precipitation method, 24 and the electrochemical deposition method by energy dispersive XRF, 25 and the filter paper method by wavelength dispersive XRF 26 have been reported. However, there are several problems in on-site workability.…”

Micro-organic Ion-associate Phase Extraction/micro-volume Back-extraction for the Preconcentration and GF-AAS Determination of Cadmium, Nickel and Lead in Environmental Water

“…Different preconcentration/separation methods are employed for quantifying trace heavy metals in water, such as liquid-liquid extraction, [2][3][4] coprecipitation, 5 solid-phase extraction, 6,7 cloud point extraction, 8,9 dispersive liquid-liquid extraction, 10 thermoresponsive polymer-mediated extraction, 11 homogeneous liquid-liquid extraction, 12 and enrichment of the membrane filter. 13 The above-mentioned separation/preconcentration techniques comprise the use of xylene, 2,4 diisobutylketone, 3 lanthanum phosphate, 5 dependence on equilibration temperature and time, 8,9 the use of trichloroethylene as an extraction solvent, 10 the application of heat, 11 or the use of a fluorine-based surfactant. 12 The metals collected on a membrane filter were determined by energy-dispersive X-ray fluorescence (EDXRF) spectrometry.…”

“…12 The metals collected on a membrane filter were determined by energy-dispersive X-ray fluorescence (EDXRF) spectrometry. 13 These methods are attainable higher enrichment.…”