Determination of spatial mercury concentration by laser ablation-inductively coupled plasma mass spectrometry

Laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) is capable of metal imaging by acquiring local spatial information. However, the preparation of an appropriate standard for quantitative analysis is difficult because the matrices between the standard and the sample should match, and homogeneity of metal concentration in the standard is required. Hence, the aim of this study was to establish a highly quantitative mercury imaging method that utilizes LA-ICP-MS and an appropriate mercury standard consisting of rat tissue. Our standard showed homogeneous mercury concentration and good linearity between concentration and signal intensity, and met the qualifications for quantitative imaging by LA-ICP-MS. Mercury concentration in MeHg-exposed rat kidneys obtained by LA-ICP-MS measurement of the standard (7.84 ± 0.57 µg/g) was comparable to that obtained by cold vapor atomic absorption spectrophotometry (AAS, 7.27 ± 0.46 µg/g). The results indicate that LA-ICP-MS enabled quantitative imaging with the appropriate standard.