[Analysis of 2,4-dibromophenol and 2,6-dibromophenol in phenolic-smelling flatfish].

A simple analytical method for dibromophenols (DBPs) in flatfiish was developed. 2,4-DBP and 2,6-DBP were extracted from a sample with acetone and n-hexane, cleaned up by treatment with conc. sulfuric acid and concentrated under a stream of nitrogen gas. The resulting extract was subjected to GC/MS. The recoveries of 2,4-DBP and 2,6-DBP were 89.4-96.5% and 81.4-86.2%, respectively, indicating that this method is useful for analysis of 2,4-DBP and 2,6-DBP. In the phenolic-smelling flatfish, 2,6-DBP was detected at the levels of 0.10 microg/g and 0.01 microg/g in skin and muscle, respectively, and 2,4-DBP was detected at the level of 0.02 microg/g in skin.

[Analysis of disulfoton sulfoxide in chingentsuai by pulsed splitless mass spectrometry using programmed temperature vaporization (PTV) inlet].

A peak considered to be due to disulfoton sulfoxide as a metabolite of disulfoton was detected in the analysis of the chingentsuai extraction solution of vegetables by GC-FPD. In the analysis by GC/MS for identification, though the retention time and the mass spectrum were the same as those of the standard, the spectrum was different from MS library data. It appeared that decomposition of disulfoton sulfoxide occurred at the inlet. Therefore, we used a programmed temperature vaporization (PTV) inlet in the pulsed splitless mode to achieve a low inlet temperature and high injection pressure. As a result, the expected mass spectrum of disulfoton sulfoxide was obtained. Under this condition, the peak obtained from chingentsuai was identified as disulfoton sulfoxide. Disulfoton sulfoxide was detected from 2 of 25 chingentsuai samples, at concentrations of 0.66 microg/g and 0.14 microg/g.

[Tricresyl phosphate residue in garland chrysanthemum and its origin].

Unknown peaks were detected in the chromatogram of garland chrysanthemum extract in analysis of organophosphorus pesticide residues. The unknown peaks were identified as isomers of tricresyl phosphate (TCP) by GC/MS. TCP is used as a plasticizer in polyvinyl chloride, and there is no report of its detection in foods. Therefore, we investigated the origin of TCP detected in garland chrysanthemum. We found no effect of contact with packaging film or polyvinyl chloride sheet used in greenhouses. However, TCP was detected at 0.03 microg/g (average) in 16 of 20 samples of garland chrysanthemum that had been in contact with polyvinyl chloride tubing used for warming greenhouses. These results indicate that TCP migrated to the garland chrysanthemum from the tubing used to keep greenhouses warm.

[Detection of tris(2,4-di-tert-butylphenyl)phosphite (Irgafos 168, antioxidant in plastics) and its oxide in commercial frozen vegetables].

Two peaks, A and B, detected in chromatograms of commercial frozen vegetable extracts during analysis of organophosphorus pesticide residues by GC-FPD, were identified as tris(2,4-ditert-butylphenyl)phosphite (Irgafos 168) and Irgafos 168 oxide, respectively, from their mass spectra. Irgafos 168 is used as an antioxidant in plastics, and there has been no report of its detection in foods. We analyzed Irgafos 168 and its oxide in 38 samples of commercial frozen vegetables, and they were detected from 4 samples (0.02-0.80 microgram/g as total amount of Irgafos 168 and its oxide).

[Identification and determination of unknown chemicals in crops by dual-column GC system equipped with MS and ECD].

A dual-column GC system equipped with MS and ECD, using two identical columns (HP-1701), one connected to the MS and one to the ECD, has been developed. The carrier gas flow rate was adjusted to give the same retention time of each peak in both columns. Unknown peaks were detected and identified in 7 samples of crops using this system. It was confirmed that the unknown peaks were 5 pesticides, i.e., bromopropylate and others. The recoveries and CV of bromopropylate from spinach and Komatsuna were good. The results of determination of bromopropylate by both MS and ECD were the same. Unknown chemicals can be easily identified using GC equipped with MS and ECD, and this system should be useful in the field of food hygiene.