Analytical Sciences

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

Takeshi KATO,*1,*2 Yuki NAGASHIMA,*1 Atsushi MANAKA,*3 Chihiro NAKAMURA,*4 Shigekatu OSHITE,*5 and Shukuro IGARASHI*6

*1 Industrial Technology Innovation Center of Ibaraki Prefecture, 3781-1 Nagaoka, Ibaraki-machi, Ibaraki 311-3195, Japan
*2 Science and Technology Promotion Division, Ibaraki Prefectural Government, 978-6 Kasahara, Mito, Ibaraki 310-8555, Japan
*3 Department of Applied Chemistry and Chemical Engineering, National Institute of Technology, Toyama College, 13 Hongo, Toyama 939-8036, Japan
*4 HORIBA Techno Service Co., Ltd., 2-6 KandaAwaji-cho, Chiyoda, Tokyo 101-0063, Japan
*5 Department of Applied Chemistry and Biochemistry, National Institute of Technology, Fukushima College, 30 Nagao, Kamiarakawa, Taira, Iwaki, Fukushima 970-8034, Japan
*6 Department of Biomolecular Functional Engineering, Faculty of Engineering, Ibaraki University, 4-12-1 Nakanarusawa, Hitachi, Ibaraki 316-8511, Japan

The rapid determination of sub-ppm heavy metals in the solution state was examined via portable X-ray fluorescence spectrometry (XRF) based on homogeneous liquid–liquid extraction (HoLLE) in the water–ethanol–dimethyl phthalate ternary component system. The percentage of cadmium extracted into the sedimented liquid phase was 91.3%. After phase separation, the volume ratio (V_a/V_s) of the aqueous phase (V_a) and the sedimented liquid phase (V_s) was 121 (29.0 → 0.240 mL). Based on an analysis of the sedimented liquid phase in the solution state via the portable XRF, the presence of cadmium was determined over a concentration range of 0.100 – 4.00 mg L⁻¹.

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