HPLC Separation of Mepiquat on Zodiac HST TH Column

Mepiquat is a plant growth regulator monitored by the EPA in water due to its environmental relevance. As a quaternary amine, mepiquat is highly polar and poses challenges for traditional reversed-phase chromatography, where it is typically not retained and often exhibits poor peak shape due to interactions with residual silanol groups. Retention generally requires ion-pairing reagents; however, such reagents are not compatible with LC/MS detection, which is essential for the high-sensitivity methods required in environmental analyses.

The Zodiac HST TH mixed-mode column offers a robust alternative, enabling effective retention and separation of highly polar ionic compounds like mepiquat. It is well-suited for EPA methods used in the determination of a wide range of pesticides, herbicides, and insecticides.