Detecting Pharmaceuticals in Water | Panyawut Cher Tonanon

Pharmaceutical residues in water — even those used for non-human applications, such as veterinary and aquarium treatments — pose an underexplored analytical challenge. I developed and optimized two complementary methods for detecting and quantifying praziquantel (PZQ), a widely used antiparasitic drug in fresh- and saltwater aquariums.

Both methods shared a common sample pretreatment strategy: solid phase extraction to quantitatively transfer PZQ into acetonitrile. From there, the samples were analyzed either by voltammetry or by gas chromatography–mass spectrometry (GC-MS) 1.

GC-MS achieved lower limits of detection (0.32 μM) and quantification (0.72 μM) than voltammetry, making it preferable where the most accurate determination is required. However, voltammetry gave acceptable quantification above 25 μM and offers a lower-cost, more portable alternative for on-site testing — an important trade-off for field-deployable environmental monitoring.

My role: Lead researcher — method development, statistical comparison, and manuscript preparation, under the supervision of Assoc Prof Richard D. Webster (NTU).

References

2024

A comparison of the detection and quantification of praziquantel \textitvia electrochemical and gas chromatography methods in freshwater and saltwater samples

Panyawut Tonanon, Katherine Jalando-On Agpoon, and Richard D. Webster

Analytical Methods, Apr 2024

Abs DOI

Two new techniques for analyzing praziquantel (PZQ), an effective antiparasitic drug used in fresh and saltwater aquariums, were optimized and compared statistically. , Two new techniques for analyzing praziquantel (PZQ), an effective antiparasitic drug used in fresh and saltwater aquariums, were optimized and compared. One method was based on voltammetry and the other method used gas chromatography combined with mass spectrometry (GC-MS), although both procedures utilized the same sample pretreatment strategy which involved the PZQ being quantitatively transferred into acetonitrile using solid phase extraction. GC-MS analysis led to lower limits of detection (0.32 μM, 0.10 ppm) and quantification (0.72 μM, 0.22 ppm) compared to voltammetry, although both methods gave acceptable quantification for levels of PZQ \textgreater 25 μM (7.8 ppm). GC-MS is preferred for the most accurate determination, but voltammetry may provide a cost-effective alternative for detecting PZQ where on site testing is required.