An analytical method for residues of the herbicide glyphosate [GLY: N-(phosphonomethyl)-glycine] and its metabolite (AMPA: aminomethylphosphonic acid) in agricultural products is described. GLY and AMPA were extracted with water (soybeans extract was moreover treated with acetone), and purified by application to a dual mini-cartridge column (octadecyl-bonded silica gel and cation-exchange silica gel) system. GLY was derivatized with 9-fluorenylmethylchloroformate, and determined by HPLC with fluorescence detection. AMPA determination was performed by HPLC employing postcolumn fluorogenic labeling with o-phthalaldehyde-mercaptoethanol. The detection limits for GLY and AMPA were 0.04 mg/g (soybean: 0.08 mg/g), and both recoveries from samples to which the compounds were added at the 0.2 mg/g level (soybean: 1.0 mg/g) were more than 65ΐ.

A sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of progesterone levels in rat plasma. Progesterone-d9 was used as an internal standard (IS). Samples were prepared using salting-out assisted liquid/liquid extraction (SALLE), and the extracts were injected directly onto the LC-MS/MS system. The chromatographic separation was achieved on a CAPCELL PAK C18 MGIII column (100 mm × 2.0 mm, i.d. 5 µm) using methanol and aqueous 0.1% formic acid solution gradient as the mobile phase with a constant flow rate of 0.45 mL/min. Electrospray ionization in the positive-ion mode was employed. Multiple reaction monitoring of the precursor to product ion pairs, from m/z 315.20 to m/z 109.10 for progesterone and from m/z 324.26 to m/z 113.07 for the IS, was used for quantification. Good linearity was observed over the concentration range of 0.05-20.00 ng/mL with a weighted (1/x(2)) linear regression. The intra- and inter-day precision (% relative standard deviation [RSD]) across 3 validation days over the entire concentration range was lower than 6.7%. Accuracy (% nominal) determined at 5 quality control concentrations was between 94.0 and 103.7%. The validation method was applied in a pharmacokinetic study evaluating progesterone levels after intramuscular or vaginal administration to ovariectomized (OVX) rats. The area under the plasma concentration-time curve (AUC) calculated after intramuscular administration was more than 4 times higher than the AUC measured following vaginal administration of a comparable dose.

No abstract

A simple determination method of diphenyl (DP) and o-phenylphenol (OPP) in agricultural products by GC/MS was examined. DP and OPP were extracted with ethyl acetate in the presence of anh. sodium sulfate. After addition of n-butanol, the extract solution was concentrated. Clean-up was achieved by shaking with graphitized bulk carbon (Supelclean ENVI-Carb). Addition of polyethylene glycol sharpened the OPP peak on GC/MS analysis.The recoveries from 9 kinds of agricultural products spiked at 0.01 and 0.5 mg/g each were mostly in the range of 70 to 120̮, except for 50̮ recovery of OPP from barley spiked at 0.01 mg/ g. The quantification limits (S/N̮10) of DP and OPP were 0.0013 and 0.005 mg/g (0.0025 and 0.01 mg/g in barley and soybean), respectively.

No abstract