In-tip solid-phase microextraction: a method for determination of sulphonamide residues in environmental water samples

ABSTRACT

This study involved the development of an in-pipette tip solid-phase microextraction (SPME) method using activated charcoal as an adsorbent. Simultaneous determination of three sulphonamide antibiotic residues in environmental water was performed using this method, coupled with high-performance liquid chromatography-photodiode array (HPLC-PDA) detection. Seven extraction parameters were optimised by one-variable-at-a-time (OVAT) and response surface (RSM) methods. Optimum extraction efficiency was achieved when 10 mL of sample solution at a natural pH (pH 5–6) was loaded through a 1 mL pipette tip packed with 10 mg of adsorbent, washed with 1 mL of hexane and eluted with 500 µL of 1% ammonium in methanol solution. Under the optimised experimental condition, this method manifested good linearity (5–500 µg L⁻¹) at the coefficient of determination, R² of 0.9992 to 0.9993, high sensitivity (limit of detection, LOD: 0.38–1.14 µg L⁻¹; limit of quantification, LOQ: 1.14–3.35 µg L⁻¹), and satisfactory recoveries (82.8–108.7%) with acceptable reproducibility (RSD < 4.6%). Real sample analysis of five environmental water samples sourced from Universiti Malaya, Kuala Lumpur and Malacca showed that the samples contained either none or traces of the target sulphonamides (SAs) with their concentration lower than the LOQs. In contrast to other methods, the comparison outcomes depicted that this in-tip SPME method was beneficial in terms of its simple, reusable, cost-saving setup together with a significant reduction in chemical consumption.

KEYWORDS:

• In-tip SPME
• activated charcoal
• sulphonamides
• HPLC-PDA
• environmental water

Acknowledgments

The authors would like to seize this opportunity to express their gratitude to Fundamental Research Grant Scheme (FP122-2020) for assistance and financial support. The authors acknowledge the Chemistry Department, Faculty of Science, Universiti Malaya for the facilities provided.

Credit authorship contribution statement

Tan Lei Lu: Writing - original draft, Methodology, Investigation, Formal analysis. Mohamad Shariff Shahriman, Kavirajaa Pandian Sambasevam, Nur Nadhirah Mohamad Zain: Writing - review and editing. Muggundha Raoov, Noorfatimah Yahaya, Vuanghao Lim: Supervision, Funding acquisition, Writing - review and editing.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have influenced the work reported in this paper.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

This work was supported by the Fundamental Research Grant Scheme (FRGS) [FP122-2020].