[Surveillance of the Naturally Derived Benzoic Acid Levels in Fruits and Fruit Products, and Comparison of Analytical Methods].

Benzoic acid (BA) is typically found in natural food; therefore, naturally occurring BA must be distinguished from added BA preservatives. In this study, we investigated BA levels in 100 samples of fruit products and their fresh fruits as raw materials using dialysis and steam distillation approaches. BA was detected in the range (minimum-maximum) of 2.1-1380 µg/g and 2.2-1950 µg/g in dialysis and steam distillation, respectively. Steam distillation indicated higher BA levels than dialysis.

Determination of nine preservatives in processed foods using a modified QuEChERS extraction and quantified by HPLC-PDA.

In this study, a new method was developed for simultaneously determining nine preservatives, that is, benzoic acid (BA), sorbic acid (SOA), dehydroacetic acid (DHA) and PHBAs (methyl p-hydroxybenzoate [PHBA-me], ethyl p-hydroxybenzoate [PHBA-et], isopropyl p-hydroxybenzoate [PHBA-ipro], propyl p-hydroxybenzoate [PHBA-npro]), isobutyl p-hydroxybenzoate [PHBA-ibut] and butyl p-hydroxybenzoate [PHBA-nbut]), in processed foods, employing liquid chromatography (LC). This procedure accelerated sample preparation and improved efficiency by employing modified quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction without clean-up. Samples were prepared with 20 mL of acetonitrile/water (1:1) with the assistance of a ceramic stone. The extract solutions were diluted 10 times or according to the detection amount and then injected into an LC-PDA. This method showed good linearity, and the LOQs were 10 mg/kg for BA, SOA and DHA and 5 mg/kg for the PHBAs. When validating this method, the recoveries of the nine preservatives were in the range 77.0-99.6%, RSDr values were in the range 0.7-5.3% and those of RSDwr were in the range 2.3-8.4%. These results suggest that this new method is highly reproducible.

[Analytical Method of PCBs in Fishes by GC-MS/MS Using an Accelerated Solvent Extractor].

An analytical method for PCBs in fishes using an accelerated solvent extractor (ASE) and GC-MS/MS was evaluated. After the extraction of ASE at 125℃ with n-hexane and clean-up with an AgNO3 silica gel/H2SO4 silica gel multilayer column, samples were analyzed by GC-MS/MS. This method was fast, effective and easy to operate. The limit of quantitation of the method was calculated to be 0.78 µg/kg for total PCBs. The recovery and the coefficient of variation of PCBs (n=5) from 6 fishes (Japanese sea perch, chub mackerel, yellowtail, salmon, pacific saury, and sardine) of total PCBs were 91-108% and 1-3%, respectively.

Determination of Fluopicolide in Livestock Products and Seafood by LC-MS/MS.

An analytical method for the determination of fluopicolide in livestock products and seafood was developed using LC-MS/MS. Sodium chloride was added to livestock products and seafood samples and fluopicolide was extracted twice with acetone after acidification with formic acid. The fat from the crude extract was removed using a macroporous diatomaceous earth column, followed by purification with a combination of mini-columns of GC (graphite carbon) and PSA (ethylenediamine-N-propyl silylation silica gel). The average recovery (n=5) of fluopicolide from 10 types of livestock products and seafood (cattle fat, cattle liver, cattle muscle, chicken, eel, egg, freshwater clam, honey, milk and salmon) spiked at the MRLs or at the uniform limit (0.01 ppm) was 96-100%, with a relative standard deviation of 2.3-6.2%. The limit of quantitation of the developed method was calculated to be 0.01 mg/kg.

[Single-laboratory validation study of simple and simultaneous determination method for pesticide residues in meat by LC-MS/MS].

We performed a single-laboratory validation study of a simple and simultaneous determination method for pesticide residues in meat using LC-MS/MS. Water was added to the sample and the mixture was homogenized. Next, pesticides were extracted with acetonitrile containing 1 vol% formic acid using a homogenizer, and salted out with magnesium sulfate, trisodium citrate and sodium chloride. After centrifugation, the acetonitrile layer was made up to standard volume and analyzed by LC-MS/MS. This method was assessed by performing recovery tests in retail bovine, swine and chicken muscle samples spiked with the 132 pesticides at the levels of 0.01 and 0.04 µg/g. Among them, 125 pesticides satisfied the Japanese method validation guideline criteria in bovine, 120 in swine and 127 in chicken.

[Simple analytical method of bromine in fruits and grain products with wavelength dispersive X-ray fluorescence spectrometer].

A simple analytical method was developed for the determination of total bromine in fruits and grain products by means of wavelength dispersive X-ray fluorescence spectrometry (WDXRF).Five gram samples of fresh fruits, frozen fruits, dried fruits and grain products were extracted with distilled water twice and diluted to 25 mL with distilled water. The sample solution (0.5 mL) was dripped onto the filter paper, which was dried and analyzed by WDXRF. The working curve was linear in the range of 0 to 10 microg/mL. Recoveries at the level of 5 microg/g were 76-104%. The detection limit was 0.5 microg/g and the determination limit was 1.5 microg/g in foods. Compared to the GC-ECD method, this method gave equivalent results for fresh fruits, frozen fruits and grain products. In addition, some dried fruits, in which a slightly high level was detected, gave almost the same results with the GC-ECD method. Therefore, this method is considered to be available as an alternative to the GC-ECD method.