A multi-residue screening method was developed for the simultaneous analysis of 73 pesticides and their metabolites using high-performance liquid chromatography coupled with electrospray tandem mass spectrometry. These pesticides were determined under a single set of experimental conditions involving a simple acetonitrile extraction without the requirement for a clean-up step. Validation was achieved at 0.01 and 0.1 mg kg À1 levels in apple, lettuce and orange. Recoveries were in the range 77-124% for the majority of pesticides. # Crown

The initial objective was to check samples of Shiitake mushrooms for potential contamination with formaldehyde. A small number of UK retail samples were analysed using a spectrophotometric method and were found to produce formaldehyde concentrations ranging from 110-240 mg kg(-1). A more specific method, based on a derivative that could be measured and characterized by LC-MS, confirmed these results. A secondary objective tested the hypothesis that the formaldehyde might be of natural origin. Samples of UK and Chinese Shiitake, verified as being produced without any formaldehyde treatments, were found to produce similar levels of formaldehyde ranging from 100-320 mg kg(-1). Frying for 6 min significantly reduced formaldehyde concentrations, whereas storage for up to 10 days had no effect on the concentrations. The relatively harsh analytical conditions used may have produced some of the formaldehyde measured during extraction, from a number of chemical precursors.

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We report a method which we have used routinely for the determination of chlormequat residues in pears. After extraction with methanol, determination was performed, without clean-up, by ion-exchange HPLC using an SCX column eluted with aqueous ammonium formate-methanol, and HPLC-MS with an electrospray interface. MS and MS-MS were employed concurrently, using selected ion monitoring and selected reaction monitoring, respectively, of the 35Cl and 37Cl isotopes of the chlormequat cation and the CID transitions of each of these precursors to the common product ion at m/z 58. The method was suitable for determinations at concentrations of chlormequat cation of 0.04 mg kg-1. Concentrations determined using the four signals were in good agreement (mean RSD 3%). The mean recovery of chlormequat cation at 0.16 mg kg-1, measured using the m/z 122-->58 signal, was 86% (RSD 7%) under repeatability conditions and 88% (RSD 15%) in routine application of the method over a 3 month period. Analysis of an in-house reference sample of pears, similarly analysed over the 3 month period, gave an RSD of 10% with a mean of 0.14 mg kg-1. Mean recovery at 0.016 mg kg-1, under repeatability conditions on two occasions, was 101% (RSD 6%) and 56% (RSD 12%).

We report the development of a qualitative method to detect the addition of blood-based binding agents to food products. The method is based on the detection of species-specific marker peptides, fibrinopeptides, released from the blood protein fibrinogen during gelling of the blood protein by thrombin. The fibrinopeptides were isolated from foods spiked with commercial bovine binding agent by acid precipitation followed by enrichment using solid-phase extraction and analysed by liquid chromatography electrospray ionisation triple quadrupole mass spectrometry. Fibrinopeptide A was found to be an effective marker in fresh, processed and cooked food matrices spiked with 5% (v/w) bovine binding agent.