Determination of Paraquat and Diquat in Potato by Liquid Chromatography/Tandem Mass Spectrometer

Narong Chamkasem, Cynthia Morris, Tiffany Harmon


A high-throughput liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed for the determination of paraquat and diquat in potatoes using a reversed-phase with weak anion-exchange and cation-exchange mixed-mode Acclaim™ Trinity Q1 column. Five grams of sample was shaken with fifteen milliliters of 1:1 MeOH: 0.1 N HCl for 10 min at room temperature and heated for 15 min at 80°C. After centrifugation, the supernatant was passed through an Oasis HLB SPE to retain suspended particulates and non-polar interferences. The sample was directly injected and analyzed for 10 min by LC-MS/MS with no sample concentration. Two multiple reaction monitoring (MRM) channels were monitored in the method for each target compound to achieve true positive identification. Two internal standards corresponding to each analyte were used to counter matrix suppression effect. Linearity of the detector response with a minimum coefficient of determination (r2) of more than 0.997 was demonstrated in the range from 2 to 250 ng/mL for each analyte using matrix-matched standard. The average recovery for all analytes at 10, 25, 100, and 500 ng/g (n$=$5) are between 87-106% with a relative standard deviation of less than 12%.


paraquat, diquat, potatoes, LC-MS/MS, determination

Full Text:



Alexander, L. N., Nuijs, V., Tarcomnicu, I., & Covaci, A. (2011). Application of hydrophilic interaction chromatography for the analysis of polar contaminants in food and environmental samples. Journal of Chromatography: A, 1218, 5964-5974.

Almeida, R. M., & Yonamine, M. (2007). Gas chromatographic-mass spectrometric Method for the determination of the Herbicides paraquat and diquat in plasma and urine samples. Journal of Chromatography: B, 853, 260-264.

Anastassiades, M., Kolberg, D. I., Mack, D., Sigalova, I., Roux, D., & Fügel, D. (2013). Quick Method for the Analysis of Residues of numerous Highly Polar Pesticides in Foods of Plant Origin involving Simultaneous Extraction with Methanol and LC-MS/MS Determination (QuPPe$-$Method). Retrieved July1, 2016, from

Aramendia, M. A., Borau, V., Lafont, F., Marinas, A., Marinas, J. M., Moreno, J. M., Porras, J. M., & Urbano, F. J. (2006). Determination of diquat and paraquat in olive oil by ion-pair liquid chromatography-electrospray ionization mass spectrometer (MRM). Food Chemistry 97, 181-188.

Awadalla, E. A. (2012). Efficacy of vitamin C against liver and kidney damage induced by paraquat toxicity. Experimental and Toxicologic Pathology, 64, 431-434.

Bassarab, P., Williams, D., Dean, J. R., Ludkin, E., & Perry, J. J. (2011). Determination of quaternary ammonium compounds in seawatersamples by solid-phase extraction and liquid chromatography-mass spectrometry. Journal of Chromatography: A, 1218, 673-677.

Cassiano, N. M., Barreiro, J. C., Martins, L. R. R., Oliveira, R. V., & Cass, Q. B. (2009). Chromatographic methods validation for analysis of small molecules in biological matrices. Química Nova, 32,1021-1030.

Castro, R., Moyano, E., & Galceran, M. T. (2001). Ion-trap versus quadrupole for analysis of quaternary ammonium herbicides by LC-MS. Chromatographia, 53, 273-278.

Chamkasem, N., & Harmon, T. (2016). Direct determination of glyphosate, glufosinate, and AMPA in soybean and corn by liquid chromatography/tandem mass spectrometry. Analytical and Bioanalytical Chemistry, 408 (18), 4995-5004.

Chamkasem, N., & Morris, C. (2016). Direct Determination of 2,4-dichlorophenoxyacetic acid in Soybean and Corn by Liquid chromatography/tandem mass spectrometry. Journal of Regulatory Science, 2, 9-18.

Chen, Y. W., Yang, Y. T., Hung, D. Z., Su, C. C., & Chen, K. L. (2012). Paraquat induces lung alveolar epithelial cell apoptosis via Nrf-2-regulated mitochondrial dysfunction and ER stress. Archives of Toxicology, 86, 1547-1558.

De Bora, B. & Rohrer, J. (n.d.). Improved Separation of Diquat and Paraquat Using the Acclaim Mixed-Mode HILIC-1 Column. Retrieved from

European Commission Directorate-General for Health and Food Safety. (2013). Guidance document on analytical quality control and validation procedures for pesticide resuides analysis in food and feed. Retrieved from $

Kolberg, D. I. S., Mack, D., Anastassiades, M., Hetmanski, M. T., Fussell, R. L., Meijer, T., & Mol, H. G. J. (2012). Development and independent laboratory validation of a simple method for the determination of paraquat and diquat in potato, cereals and pulses. Analytical and Bioanalytical Chemistry, 404, 2465-2474.

Monsanto International sàrl & Monsanto Europe SA. (2010). The agronomic benefits of glyphosate in Europe. Retrieved from

Philbey, A. W., & Morton, A. G. (2001). Paraquat poisoning in sheep from contaminated water. Australian Veterinary Journal, 79 (12), 842-843.

Pizzutti, I. R., Vela, G. M. E., de Kok, A., Scholten, J. M., Dias, J. V., Cardoso, C. D., Concenço, G., & Vivian, R. (2016). Determination of paraquat and diquat: LC-MS method optimization and validation. Food Chemistry, 209, 248-255.

Schaner, A., & Hickes, H. (2015). Quantitative analysis of paraquat in vegetation by stable isotope dilution and liquid chromatography/electrospray ionization-mass spectrometry. Journal of AOAC International, 98, 512-516.

Selisker, M. Y., Herzog, D. P., Erber, R. D., Fleeker, J. R., & Itak, J. A. (1995). Determination of paraquat in fruits and vegetables by a magnetic particle based enzyme-linked-immunosorbent assay. Journal of Agricultural and Food Chemistry, 43, 544-547.

Tadeo, J. L., Sanchez-Brunete, C., Perez, R. A., & Fernandez, M. D. (2000). Analysis of herbicide residues in cereals, fruits and vegetables. Journal of Chromatogrophy: A, 882, 175-191.

Taylor, P. J., Salm, P., & Pillans, P. I. (2001). A detection scheme for paraquat poisoning: validation and a five-year experience in Australia. Journal of Analytical Toxicology, 25 (6), 456-460.

Thermo Scientific. (n.d.). Acclaim Trinity Q1 Columns for trace analysis of diquat and paraquat. Retrieved from

Tolerances and Exemptions for Pesticide Chemical Residues in Food, 40 CFR 180 (2016). Retrieved July 1, 2016.

Wigfield, Y .Y., McCormack, K. A., & Grant, R. (1993). Simultaneous determination of residues of paraquat and diquat in potatoes using high-performance capillary electrophoresis with ultraviolet detection. Journal of Agricultural and Food Chemistry, 41, 2315-2318.

Yao, F., Liu, H., Wang, G., Du, L., Yin, X., & Fu, Y. (2013). Determination of paraquat in water samples using a sensitive fluorescent probe titration method. Journal of Environmental Sciences, 25, 1245-1251.

Zou, T., He, P., Cao, J., & Li, Z. (2015). Determination of Paraquat in vegetables using HPLC-MS-MS. Journal of Chromatographic Science, 53, 204-209.