In this study, we simultaneously determined three antioxidants, butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), and tert-butylhydroquinone (TBHQ), using HPLC equipped both with a photodiode array detector and a fluorescence detector in 25 minutes per sample. Due to the combined use of the two detectors, we could achieve improved target selectivity. Further, quantification at the specific wavelengths for each target substance particularly increased BHT detection sensitivity. This approach enabled us to avoid repeated measurements during daily inspections. Furthermore, detections were performed using LC-MS/MS instead of GC-MS to overcome the problem of helium gas shortage.In addition, we investigated antioxidant stability in standard solutions during storage. Although TBHQ was stable in methanol with ascorbic acid at -20℃, ascorbic acid storage has possibility to lead to decrease in BHT and BHA concentrations. We recognized that the mixture of BHT and BHA dissolved in methanol at 4℃ and that of BHT, BHA and TBHQ dissolved in methanol with ascorbic acid at -20℃ were suitable for about one year.
The prevalence of health food use is increasing not only among healthy individuals but also among patients. Many patients consume drugs and health foods concomitantly, and most of them use more than one drug and one health food. In this regard, the interactions between drugs and health foods should be addressed. However, it is not clear where healthcare professionals can get sufficient information about the interactions between drugs and health foods. To address this issue, we conducted an online questionnaire about the consultation and attitude concerning and information source of interactions between drugs and health foods among pharmacists and dietitians. Only 29.7% of pharmacists and 14.0% of dietitians always confirmed the use of health foods among their patients, even though they work at pharmacies or hospitals. Regarding concomitant use, 79.2% of pharmacists and 60.2% of dietitians allowed their patients to continue concomitant use, and less than 20% of them advised their patients to avoid concomitant use. Most of them checked the manufacturer's website and could not obtain sufficient information about the interactions between drugs and health foods. However, they utilized the "Information system on safety and effectiveness for health foods (HFNet)," which is the website of the National Institutes of Biomedical Innovation, Health and Nutrition, to obtain information, if they were aware of this. In conclusion, pharmacists and dietitians need more information about the interactions between drugs and health foods, and HFNet may play an important role as information source.
An analytical method based on LC-MS/MS was developed for the determination of chlorothalonil metabolite I in livestock products. Chlorothalonil metabolite I in livestock products was extracted with acetone. The crude extracts were defatted by acetonitrile and n-hexane partitioning. Cleanup was carried out using a combination of ethylene diamine-N-propyl silylation silica gel (PSA) and silica gel (SI) mini columns with acidic condition. The sample solution was subjected to LC-MS/MS using an external solvent calibration curve. The average recovery (n=5) of chlorothalonil metabolite I from five types of livestock products (cattle muscle, cattle fat, cattle liver, milk and egg) spike at the maximum residue limits (MRLs) or at a uniform limit of 0.01 mg/kg was 97.1-102.9%, with a relative standard deviation of 1.4-6.8%. The limit of quantitation of the developed method was calculated to be 0.01 mg/kg.
A collaborative study for validating the determination method of chlorpropham in feeds by LC-MS/MS was conducted in 13 laboratories using 2 kinds of formula feeds, oats, barley, wheat, and corn. The resulting trueness ranged from 75.3 to 87.0%, repeatability and reproducibility in terms of relative standard deviation (RSDr and RSDR) were within 7.3% and 33% respectively, and the HorRat values ranged from 0.39 to 1.5. The limit of detection and limit of quantitation of chlorpropham in feed ware 0.008 mg/kg and 0.003 mg/kg, respectively. This method was thus validated as useful for inspections of chlorpropham in feed.
A rapid, easy and versatile, simultaneous analytical method based on three-layer extraction was developed for the determination of 6 fungicides in lemon. In this method, degreasing with n-hexane, partitioning into acetonitrile, and purification by the salting-out effect were simultaneously performed after extraction with acetone. It allowed to prepare a test solution without concentrating, transferring, and purification using solid phase extraction column. As a result, 6 fungicides in lemon met the management criteria of the guideline for validity assessment (Ministry of Health, Labour and Welfare in Japan). Thus, the present method could be useful for a rapid determination of fungicides in lemon.
