DETERMINATION OF ZINC PHOSPHIDE RESIDUES IN THE CALIFORNIA GROUND SQUIRREL (SPERMOPHILUS BEECHEYI) BY GAS CHROMATOGRAPHY FLAME PHOTOMETRIC DETECTION

摘要

Zinc phosphide (Zn3P2) recovery from small mammal tissues is assessed for the first time by an analytical method developed for the determination of Zn3P2 residues in the gastrointestinal (GI) tracts of California ground squirrels (Spermophilus beecheyi) by gas chromatography-flame photometric detection (GC-FPD). GI tracts from field-collected squirrels were removed, and the stomachs and intestines were separated. Emptied stomachs were fortified with varying combinations of Zn3P2 and partially digested range grass; intestines were-fortified with Zn3P2 only. Tissues were processed and acid hydrolyzed in a sealed flask to produce phosphine (PH3) gas, and samples of the PH3-containing headspace gas were analyzed by GC. Recovery data were used to develop predictive linear equations relating tissue weights and Zn3P2 observed with actual Zn3P2 residues. The validated linear range was 0.1-103.4 pg of Zn3P2/mL headspace (0.102-100.3 mg of Zn3P2/sample, r(2) = 0.9993). The limits of detection of the method were 0.015 mg (approximate to 250 ppb) and 0.013 mg (approximate to 154 ppb) in stomachs and intestines, respectively. No chromatographic interferences were observed.