Fluorescence Quenching Method for Determination of Trace Tungsten in Soil after Cloud Point Extraction

Abstract

A new procedure for trace tungsten W(VI) in soil by fluorescence quenching method coupled with cloud point extraction (CPE) as the separation-preconcentration method was described. The Triton X-100 CPE behavior of W(VI)-salicylfluorone (SAF)was investigated. Under the optimized conditions, the fluorescence quenched intensity (ΔF) was linearly with W(VI). The range of linear was 0.8 ∼ 20.0 μg · L⁻¹, the detection limit (DL) was 0.14 ng · mL⁻¹ (3σ), the relative standard deviation 3.3% (c = 10.0 μg · L⁻¹, n = 5) and the recovery was 101.0–102.2%. The proposed method applied to the analysis of W(VI) in certified reference materials and real samples.

Keywords:

• Cloud point extraction
• Fluorescence quenching method
• Salicylfluorone
• Tungsten

The authors acknowledge the financial support from the National Natural Science Foundation of China (20875082) and the Foundation of the Educational Committee of Jiangsu Provincial Universities Excellence Science and Technology Invention Team in Yangzhou University.

Notes

^a National reference materials (Standard Tibet Soil 83401, Research Center for Eco-Environmental Sciences, The Chinese Academy of Sciences).

Sample A: sampled from campus lawn; Sample B: sampled from suburb tea soil garden.