Liquid chromatographic determination of paraquat and diquat in crops using a silica column with aqueous ionic mobile phase. 1991

T M Chichila, and S M Walters
Food and Drug Administration, Pesticides and Industrial Chemicals Research Center, Detroit, MI 48207.

A method was developed for the determination of paraquat (PQ) and diquat (DQ) in high moisture food crops. Samples were digested with 6M HCl, and the herbicides were isolated from the digest using pH-controlled silica solid phase extraction. The analytes were then determined by ion-pairing liquid chromatography with a silica analytical column, sodium chloride as the ion-pairing reagent, and acetonitrile as the organic modifier. A diode array UV absorbance detector was used to simultaneously quantify PQ and DQ at their respective maximum absorbance wavelengths, 257 and 310 nm. Average recoveries of PQ and DQ standards from 4 different crops fortified at 0.01-0.50 ppm levels ranged from 79.3 to 104.8%.

UI MeSH Term Description Entries
D010269 Paraquat A poisonous dipyridilium compound used as contact herbicide. Contact with concentrated solutions causes irritation of the skin, cracking and shedding of the nails, and delayed healing of cuts and wounds. Methyl Viologen,Gramoxone,Paragreen A,Viologen, Methyl
D010945 Plants, Edible An organism of the vegetable kingdom suitable by nature for use as a food, especially by human beings. Not all parts of any given plant are edible but all parts of edible plants have been known to figure as raw or cooked food: leaves, roots, tubers, stems, seeds, buds, fruits, and flowers. The most commonly edible parts of plants are FRUIT, usually sweet, fleshy, and succulent. Most edible plants are commonly cultivated for their nutritional value and are referred to as VEGETABLES. Food Plants,Edible Plant,Edible Plants,Food Plant,Plant, Edible,Plant, Food,Plants, Food
D002853 Chromatography, Liquid Chromatographic techniques in which the mobile phase is a liquid. Liquid Chromatography
D004178 Diquat A contact herbicide used also to produce desiccation and defoliation. (From Merck Index, 11th ed) Diquat Dibromide,Dibromide, Diquat
D006863 Hydrogen-Ion Concentration The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH pH,Concentration, Hydrogen-Ion,Concentrations, Hydrogen-Ion,Hydrogen Ion Concentration,Hydrogen-Ion Concentrations
D012822 Silicon Dioxide Transparent, tasteless crystals found in nature as agate, amethyst, chalcedony, cristobalite, flint, sand, QUARTZ, and tridymite. The compound is insoluble in water or acids except hydrofluoric acid. Silica,Aerosil,Aerosil 380,Cristobalite,Quso G-32,Quso G32,Tridymite,380, Aerosil,Dioxide, Silicon,G32, Quso,Quso G 32
D012965 Sodium Chloride A ubiquitous sodium salt that is commonly used to season food. Sodium Chloride, (22)Na,Sodium Chloride, (24)NaCl

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