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A microbore high performance liquid chromatographic/electrospray/mass spectrometric (HPLC/ESI-MS) method has been developed for the determination of the phytoestrogens daidzein and genistein in soya flours and baby foods. The samples were hydrolysed and extracted with acetonitrile-water prior to analysis. LC was performed on a microbore Primesphere 5C8 column using a water/acetonitrile/acetic acid mobile phase at a flow rate of 60 microliters/min. Atmospheric pressure ionization in the form of pneumatically assisted electrospray mass spectrometry (ESI-MS) was used as the method of detection. The limit of detection was 0.2 mg/ kg for daidzein and 0.7 mg/kg for genistein in the flour and food samples. The method proved both robust and reliable when operated over a long time period (10 days, 463 injections) generating precision data with a coefficient of variation of 4-15%.

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: Two analytical methods are presented for the determination of 2,4-D in oranges.The screening procedure uses a commercial ELISA kit, designed for the determination of 2,4-D in water. Good semi-quantitative screening data were obtained provided that the standard solutions used to construct the calibration curve were prepared in blank orange extract. The limited quantiÐcation range of the kit was due to the narrow linear range and di †erences in response to 2,4-D when present as the free acid and as various esters.A GC-MS conÐrmatory technique involved extraction of 2,4-D from oranges by homogenisation with methanol, Ðltration and esteriÐcation/transesteriÐcation with boron triÑuoride-methanol. Recoveries for three spiking levels (0É2, 1É0 and 2É0 mg kg~1) for 2,4-D and 2,4-D isopropyl ester were within the range 75È 120%.In a small survey of retail oranges, 10 samples were screened using the ELISA kit and four were found to have [0É2 mg 2,4-D kg~1. All four residues were conÐrmed by GC-MS. The ELISA procedure involves approximately half the sta † e †ort of the GC-MS procedure.