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Under European legislation, domoic acid (DA), the main constituent of amnesic shellfish poisoning, is monitored to protect the shellfish consumer. To ensure comparability amongst analytical data, it was deemed necessary to undertake performance assessments of the methods conducted by monitoring laboratories of the United Kingdom and Ireland.In phase I of a two-phase inter-comparison, three laboratories used high-performance liquid chromatography and ultraviolet detection (HPLC-UV). Concentration data for a DA standard solution, a crude extract of whole scallops and a scallop-homogenate fell within internationally accepted limits, demonstrating good agreement for these matrices. Between-laboratory analyses of a scallop gonad showed a higher variation (>16%).In phase II, a second gonad homogenate containing DA one order of magnitude higher in concentration gave results acceptable to internationally set criteria.The efficiency of the strong anion-exchange cartridges used in sample-extract clean-up should be monitored as part of a laboratory quality control system.From a recovery study, it is suggested that recovery correction should also be applied. There was no difference in the quantitation of DA in standard solutions or shellfish using either LC-UV or LC with mass spectrometric (MS) detection, and between-laboratory MS data for a gonad homogenate were also equivalent.Variations of the published method practised by the monitoring laboratories were found not to compromise results, thus demonstrating an acceptable degree of ruggedness, as well as comparability between the participants.

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14 15 A survey was carried out on the occurrence of dinitrocarbanilide (DNC) the marker residue for 16 nicarbazin, in poultry produced in Ireland during the years 2002 to 2004. Liver (n = 736) and breast 17 muscle samples (n = 342) were tested. DNC residues were found in 40% and 26% of liver and 18 breast muscle samples at levels greater than 12.5 and 5 µg kg-1 , respectively. DNC residues were 19 found at >200 µg kg-1 in 12 and 0% of liver and muscle samples, respectively. Samples of breast 20 muscle (n = 217) imported from 11 countries were also tested for DNC residues. A lower incidence 21 of DNC residues (6%) was found in imported breast muscle. Egg samples (n = 546) were tested 22 and DNC residues were found in nine samples, with levels ranging between 14 and 122 µg kg-1. 23 Analysis of poultry, carried out as part of official food inspection in the period 2004 to 2006, 24 indicated a reduction in the number of broiler liver samples containing DNC at >200 µg kg-1 , to 25 approximately 7%. Low levels of DNC residues continue to be found in <2% of egg samples. 26 27 dimethylpyrimidine (HDP). It is administered to poultry in feed for the prophylactic treatment of 30 coccidiosis. Coccidiosis is an infectious disease caused by a microscopic protozoan parasite, 31 which damages the intestinal tract of the bird, causing illness and sometimes death. Intensively 32

A rapid gradient method has been established to measure simultaneously the tissue levels of S-adenosylmethionine (AdoMet) and S-adenosylhomocysteine (AdoHcy). The method involves application of a 15%-25% linear gradient of methanol over a period of 10 min to an initial mobile phase of 15% methanol with 25 mM sodium phosphate, 10 mM 1-heptanesulfonic acid solution at pH 3.2 and a flow rate of 1 mL/min. AdoHcy elutes at 9.5 min and AdoMet at 12.6 min. The assay has a detection limit of 10 pmol and is linear in the concentration range 30-800 pmol. The method was used to assess changes in AdoMet and AdoHcy concentrations of pig tissues after seven days exposure to the anaesthetic gas nitrous oxide which irreversibly inactivates methionine synthase and induces an inability to recycle homocysteine, particularly in neural tissues. The treatment caused significant alterations in cellular AdoMet:AdoHcy ratios which were principally due to a dramatic rise in AdoHcy concentrations.