Speciation and determination of inorganic antimony in tea infusion by using solid-phase extraction-based liquid chromatography-inductively coupled plasma-mass spectrometry

Abstract

In this work, we developed a method to separate and detect inorganic antimony (iSb) in tea infusions based on liquid chromatography-inductively coupled plasma-mass spectrometry (LC-ICP-MS). Considering that iSb was present in tea infusions in trace amounts, a commercial solid-phase extraction (SPE) column was employed to enrich iSb(III) and iSb(V). In this study, we found that iSb exists in tea infusions in a bound state with an unknown substance rather than in a free state. Therefore, the enrichment step was combined with oxidation and reduction processes. Because of the enrichment process and the high sensitivity of LC-ICP-MS, the LODs of iSb(III) and iSb(V) were both as low as 0.03 μg L⁻¹. The RSDs (n = 6) of iSb(III) and iSb(V) were all below 8.1%, and the recoveries (n = 6) were 92–96% and 90–94%, respectively. Then, a total of six tea infusion samples were inspected. The data revealed that the total Sb in the tea infusions ranged from 0.22 to 0.97 μg L⁻¹, and we found that 50–83% of the total Sb in the tea infusion was iSb. This method is worth promoting since it has satisfying methodological performance.

Graphical abstract

Keywords:

• Inorganic antimony
• liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS)
• solid-phase extraction (SPE)
• speciation
• redox
• tea infusion

Author contribution

Hu Jiacai: conceptualization, data curation, formal analysis, investigation, methodology, writing-original. Xiuming Lv: writing & editing, investigation, methodology. Zhang hao: investigation, methodology. Zhu Baoli, Liu Deye and Ji Wenliang: conceptualization, project administration, resources; supervision.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was funded by the Jiangsu Provincial Medical Youth Talent of Jiangsu Province, China (QNRC2016540), Jiangsu Provincial Key Medical Discipline of Jiangsu Province, China (ZDXK202249) and the Key Project and Open Research Fund of the State Key Laboratory of Bioelectronics, Southeast University.