An analytical method for the determination of butroxydim in agricultural products by LC-MS was developed. Butroxydim was extracted with acetonitrile and an aliquot of the crude extract was cleaned up on an octadecyl silanized silica gel (C18) cartridge column (1,000 mg), followed by a salting-out step to remove water. Before purification on a silica gel (SI) cartridge column (690 mg), polar matrices were precipitated by adding ethyl acetate, n-hexane and anhydrous sodium sulfate successively. This process effectively removed caffeine and catechins and improved recovery when analyzing residual butroxydim in tea leaves. Recovery and repeatability were good; the relative standard deviations were less than 5% for all 12 tested agricultural products (brown rice, soybean, potato, spinach, cabbage, apple, orange, grapefruit, lemon, tomato, peas with pods, and tea). Average recoveries for 11 agricultural products, except for lemon, were 74–92%.
Five kinds of commercially available ELISA kits (acetamiprid, azoxystrobin, chlorothalonil, fenitrothion and imidacloprid) were validated for determination of pesticide residues in vegetables and fruits. The reaction characteristics were also examined to evaluate their influence on the determinations. The trueness value was 91–162%, the repeatability was 2.1–16.2%, and the reproducibility was 4.0–20.3%. The desired values were achieved for 18 among 30 combinations (60%) of the ELISA kits and the agricultural products examined. A standard curve was necessary for each of the ELISA examinations. The matrix of the agricultural products and pipetting skill of the lab technician both influenced the measurment results.
We incubated Fusarium semitectum on sorghum and measured the production of zearalenone (ZEN) and ZEN-related compounds (zearalanone (ZAN), α-zearalenol (α-ZEL), β-zearalenol (β-ZEL), α-zearalanol (α-ZAL) and β-zearalanol (β-ZAL)) in the culture by LC-MS. Of the five ZEN-related compounds, ZAN and β-ZEL were mainly detected. The concentrations of ZEN and the five ZEN-related compounds increased until 9 days after incubation and then increased slightly or stayed constant between days 9 and 15. The ratios of α-ZEL, β-ZEL, α-ZAL and β-ZAL to ZEN decreased in a similar manner after 7 days, whereas the ratio of ZAN to ZEN remained constant after 5 days. Analysis of naturally contaminated sorghum by LC-MS/MS revealed that the production ratio of α-ZEL to ZEN was inconsistent with that of our in vitro incubation analysis. The results indicate that ZAN might not be suitable for use as an internal standard.
Cases of hepatitis E have been caused by infection with hepatitis E virus (HEV) due to consumption of raw or undercooked game meats and liver of wild boars or deer in various countries. We investigated HEV prevalence in wild boar and deer in Okazaki City and its outskirts, Aichi, Japan, using liver samples (439 boar; 185 deer) collected between April 2010 and November 2014. HEV RNA was detected in 49 (11.2%)of 439 and 0 of 185 samples of wild boar and deer, respectively. The positive rate (13.0%, 28/216) of HEV RNA from the wild boar with estimated body weight of less than 40 kg was significantly higher than that (2.7%, 3/111) in animals with estimated body weight of more than 40 kg. The 49 HEV strains were typed as genotype 4 (G4) by phylogenetic analysis. They clustered with Aichi/Shizuoka strains and 48 of the 49 strains subclustered together (Okazaki strains).
We developed and evaluated methods of quantifying cyanide (cyanide ion and cyanogen chloride) and bromic acid in mineral waters (MW). After performance evaluation, recovery studies were performed on 110 kinds of MW products to examine the applicability of the methods. The approximate proportion of the MW samples, in which the recovery rate of these anionic compounds was within 90 to 110%, was 95% in the cyanide ion and bromic acid analysis and 45% in the cyanogen chloride analysis. We observed low rates of recovery of cyanogen chloride from some MW products with pH values around neutral. To increase the recovery rate, we propose adding phosphoric acid buffer to adjust the pH of these MW samples. The retention times for bromic acid in some MW products differed from that in standard solution. We concluded that carbonic acid influences the retention times. It may be necessary to to exclude carbon dioxide from the MW samples by degassing to synchronize the retention times of bromic acid in the MW samples and the standard solution.