A Simple High Performance Liquid Chromatography/Ionspray Tandem Mass Spectrometry Method for the Direct Determination of Paraquat and Diquat in Water

Abstract

A method has been developed for the direct determination of paraquat and diquat in water samples. No sample preparation was required and analysis was done using high performance liquid chromatography coupled with ionspray tandem mass spectrometry. Heptafluorobutyric acid was used as the ion-pair agent. Further improvements in this method included the incorporation of an internal standard (caffeine). Using this method, detection limits of 5 and 1 µg/L were obtained for paraquat and diquat respectively. Recoveries were consistently > 90% with relative standard deviations of < 10% over the concentration range 5-100 µg/L. To our knowledge, this method is the first application of ionspray tandem mass spectrometry, and the first to use heptafluorobutyric acid as an ion-pair reagent, for the analysis of paraquat and diquat.

Electrochemical determination of paraquat in potato, lemon, orange and natural water samples using sensitive-rich clay carbon electrode

“…in the blank media. The reported detection limits are comparable to the previously reported methodology (Table 1) [30][31][32][33][34][35] and lower than the maximum value established by the United States Environmental Protection Agency (EPA) in drinking water.…”

A simple and rapid chemiluminescence assay for on-site analysis of paraquat using a portable luminometer

“…Also, the sensitivity of the proposed assay is almost same as those of LC-time of flight-MS [14], LC-electrospray ionization-MS [15] and LC-tandem MS [17]. Although the proposed assay is less sensitive than voltammetry [9] and GC-ion trap-MS [10], these methods required special and complex equipment.…”

“…Several methods have been reported for the analysis of paraquat using colorimetry [6], spectrophotometry [7], voltammetry [8], capillary electrophoresis (CE) [9], gas chromatography (GC) [10,11], high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection [12], post-column colorimetric detection [13] and mass spectrometry (MS) [14][15][16][17]. The colorimetry using hydrosulfite as a reagent is very simple and traditional assay for paraquat and has been used for on-site analysis.…”

Development of an ultra fast liquid chromatography–tandem mass spectrometry method for simultaneous determination of cefazedone and etimicin in beagle dog plasma: Application to the pharmacokinetic study of the combination of cefazedone and etimicin injections

“…Heptafluorobutyric acid (HFBA) was chosen as the ion-pair reagent in the present work. As modifiers in reversed phase LC, HFBA could prolong retention via forming ion pair with cation of etimicin, as well as improve peak shape by suppressing the interactions of the ionic etimicin with the active silanol sites on the column [26,27]. Moreover, this acid was volatile and was compatible with LC-MS/MS.…”