Zinc Phosphide Residue Determination in Alfalfa (Medicago sativa)

• Published in: Journal of agricultural and food chemistry Vol. 45; no. 6; pp. 2107 - 2111
• Main Authors: Mauldin, Richard E, Goodall, Margaret J, Volz, Stephanie A, Griffin, Doreen L, Petty, Eric J, Johnston, John J
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.06.1997
• Subjects: ANALYTICAL METHODS; Biological and medical sciences; CHEMICAL COMPOSITION; CHROMATOGRAPHIE EN PHASE GAZEUSE; COMPOSICION QUIMICA; COMPOSITION CHIMIQUE; CROMATOGRAFIA DE GASES; ESPECTROFOTOMETRIA DE LLAMA; Feed and pet food industries; FLAME PHOTOMETRY; Food industries; Fundamental and applied biological sciences. Psychology; GAS CHROMATOGRAPHY; PESTICIDE; PESTICIDES; PLAGUICIDAS; RESIDU; RESIDUES; RESIDUOS; SPECTROPHOTOMETRIE DE FLAMME; TECHNIQUE ANALYTIQUE; TECNICAS ANALITICAS; Hay; Fodder; Rodenticide; Gas chromatography; Flame photometer; Residue; Quality control; Analytical method; Zinc phosphide; Lucerne; Feed; Quantitative analysis; Chemical contamination
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf960689k

An analytical method for the determination of zinc phosphide (Zn3P2) residues in alfalfa ranging from 10 μg g-1 to 100 mg g-1 is described. Using a suspension of Zn3P2 in propylene glycol, Zn3P2 standards were prepared and midharvest alfalfa and dried hay control samples fortified to assess method recovery. Addition of 1% phosphoric acid to Zn3P2-containing samples produced phosphine (PH3) gas for headspace gas chromatography/flame photometric detection analysis. Response linearity was assessed for (8.9 × 10-5)−0.027 μg of Zn3P2 mL-1 headspace (r 2 = 0.9914) and 0.027−2.02 μg of Zn3P2 mL-1 headspace (r 2 = 0.9998) concentration ranges. Analyte recovery exceeded 81% for Zn3P2 fortification levels ranging from 0.010 to 100 μg g-1, and the method limit of detection was 2.1 × 10-3 μg g-1 in midharvest alfalfa and 3.9 × 10-3 μg g-1 in dried hay. Keywords: Zinc phosphide; phosphine; residues; Medicago sativa; alfalfa; gas chromatography/flame photometric detection