Determination of Flunixin and 5-Hydroxy Flunixin Residues in Livestock and Fishery Products Using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS).

Flunixin is a veterinary nonsteroidal anti-inflammatory agent whose residues have been investigated in their original form within tissues such as muscle and liver. However, flunixin remains in milk as a metabolite, and 5-hydroxy flunixin has been used as the primary marker for its surveillance. This study aimed to develop a quantitative method for detecting flunixin and 5-hydroxy flunixin in milk and to strengthen the monitoring system by applying to other livestock and fishery products. Two different methods were compared, and the target compounds were extracted from milk using an organic solvent, purified with C18, concentrated, and reconstituted using a methanol-based solvent. Following filtering, the final sample was analyzed using liquid chromatography- tandem mass spectrometry. Method 1 is environmentally friendly due to the low use of reagents and is based on a multi-residue, multi-class analysis method approved by the Ministry of Food and Drug Safety. The accuracy and precision of both methods were 84.6%-115% and 0.7%-9.3%, respectively. Owing to the low matrix effect in milk and its convenience, Method 1 was evaluated for other matrices (beef, chicken, egg, flatfish, and shrimp) and its recovery and coefficient of variation are sufficient according to the Codex criteria (CAC/GL 71-2009). The limits of detection and quantification were 2-8 and 5-27 µg/kg for flunixin and 2-10 and 6-33 µg/kg for 5-hydroxy flunixin, respectively. This study can be used as a monitoring method for a positive list system that regulates veterinary drug residues for all livestock and fisheries products.

Multiclass Method for the Determination of Anthelmintic and Antiprotozoal Drugs in Livestock Products by Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry.

The objective of this study was to establish a multi-residue quantitative method for the analysis of anthelmintic and antiprotozoal drugs in various livestock products (beef, pork, and chicken) using ultra-high-performance liquid chromatography-tandem mass spectrometry. Each compound performed validation at three different levels i.e., 0.5, 1, and 2× the maximum residue limit according to the CODEX guidelines (CAC/GL 71-2009). This study was conducted according to the modified quick, easy, cheap, effective, rugged, and safe procedure. The matrix-matched calibrations gave correlation coefficients >0.98, and the obtained recoveries were in the range of 60.2%-119.9%, with coefficients of variation ≤32.0%. Furthermore, the detection and quantification limits of the method were in the ranges of 0.03-3.2 and 0.1-9.7 µg/kg, respectively. Moreover, a survey of residual anthelmintic and antiprotozoal drugs was also carried out in 30 samples of beef, pork, and chicken collected in Korea. Toltrazuril sulfone was detected in all three samples. Thus, our results indicated that the developed method is suitable for determining the anthelmintic and antiprotozoal drug contents in livestock products.

Determination of Anthelmintic and Antiprotozoal Drug Residues in Fish Using Liquid Chromatography-Tandem Mass Spectrometry.

The objective of this study is to develop a comprehensive and simple method for the simultaneous determination of anthelmintic and antiprotozoal drug residues in fish. For sample preparation, we used the "quick, easy, cheap, effective, rugged, and safe" (QuEChERS) method with a simple modification. The sample was extracted with water and 1% formic acid in acetonitrile/methanol (MeCN/MeOH) (95:5, v/v), followed by phase separation (salting out) with MgSO4 and NaCl (4:1, w/w). After centrifugation, an aliquot of the extract was purified by dispersive solid-phase extraction (d-SPE) prior to liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The method was validated at three concentration levels for all matrices, in accordance with the Codex guidelines (CAC/GL-71). Quantitative analysis was performed using the method of matrix-matched calibration. The recoveries were between 60.6% and 119.9%, with coefficients of variation (CV) <30% for all matrices. The limit of quantitation (LOQ) of the method ranged from 0.02 µg kg-1 to 4.8 µg kg-1 for all matrices. This comprehensive method can be used for the investigation of both anthelmintic and antiprotozoal drugs belonging to different chemical families in fishery products.

Comparative analysis of lead content during food processing.

Heavy metals in groups 3-16 in periods 4 and greater. They exist naturally in the earth's crust. People are exposed to heavy metals by the inhalation of polluted air and via the intake of contaminated food. People are exposed to lead (Pb), one of heavy metals, by consuming foods that are contaminated from the environment. Pb is ubiquitous in the environment and accumulates in plants and animals that eat contaminated plants. The Pb in foods before and after processing were analyzed via Inductively coupled plasma with mass spectrometry to determine the effects of the procedures on the Pb migration and residue. This analytical method was verified to have a limit of detection of 0.011-0.859 µg/kg, acceptable linearity with the regression coefficient of 0.999, relative recoveries of 78.1-89.9% and repeatability of 1.4-7.7%. The amount of Pb was reduced during the following processes: more than 79.6% by extracting ginseng, extracting red ginseng and balloon flower roots via alcohol, more than 47.9% by blanching Chwinamul, more than 18.2% by brewing coffee with cold and hot water, more than 22.2% by extracting juices from fruits and peeling fruits. Therefore, proper cooking and food processing can be advantageous in terms of reducing exposure to Pb.

Methylmercury Determination in Fish by Direct Mercury Analyzer.

BACKGROUND: There are two methods for quantifying methylmercury (MeHg) in fish using GC-electron capture detection (ECD): AOAC INTERNATIONAL Official Method 988.11 and the Korean Food Code (KFC) method. Both of these methods consume a large amount of chemicals and require long pretreatment times because of several complicated MeHg extraction steps. OBJECTIVE: In this study, a new method for the simple and rapid determination of MeHg in fish has been developed. The method is based on the investigation of oxygen combustion-gold amalgamation using a direct mercury analyzer (DMA) after the complete removal of MeHg by organic extraction and back-extraction to an aqueous medium. METHODS: The DMA is suitable for the analysis of both solid and liquid materials and has a good detection limit. The developed method was validated by comparing the MeHg recoveries (%) of both certified reference materials and the market-purchased fish samples with the MeHg concentration obtained using the KFC method. RESULTS: The following parameters pertaining to the developed method were established: detection limit, 1.02 µg/kg; LOQ, 3.09 µg/kg; linearity (r), 0.9998; range, 0.1-300 µg/kg; and recovery, 95-97%. CONCLUSIONS: Our method is a promising alternative by virtue of its much simpler and faster sample pretreatment procedure, with a MeHg recovery as high as that of the KFC method. HIGHLIGHTS: The developed method enables the simultaneous analysis of total Hg and MeHg with only DMA equipment.

Improvement of a GC-MS analytical method for the simultaneous detection of 3-MCPD and 1,3-DCP in food.

Chloropropanols such as 3-monochloropropane-1,2-diol (3-MCPD) and 1,3-dichloropropan-2-ol (1,3-DCP) are produced by heat treatment in the presence of fat and hydrochloric acid during the manufacture of food stuffs such as hydrolyzed vegetable protein and soy sauce. 3-MCPD and 1,3-DCP have been detected in several foods. An efficient, highly selective GC-MS method was developed to determine the concentration of 3-MCPD and 1,3-DCP in food. Calibration curves for 3-MCPD and 1,3-DCP were constructed, and a correlation of determination (r2) ≥ 0.9990 was obtained. The limits of detection and quantitation for 3-MCPD in food were 0.6 and 2.0 µg/kg, respectively, and those for 1,3-DCP were 0.2 and 0.6 µg/kg, respectively. To the best of our knowledge, this GC-MS-based method is a newly improved analytical procedure for the simultaneous separation and determination of 3-MCPD and 1,3-DCP, at once and at low levels (µg/kg).

Isolation and structural characterization of a novel sibutramine analogue, chlorosipentramine, in a slimming dietary supplement, by using HPLC-PDA, LC-Q-TOF/MS, FT-IR, and NMR.

A novel sibutramine analogue was detected in a slimming formula by high performance liquid chromatography with a photo diode detector array (HPLC-PDA). The unknown compound exhibited an ultraviolet (UV) spectrum that was similar to that of chlorosibutramine, despite having a different HPLC retention time. Further analysis of the slimming formula by LC-quadrupole time-of-flight mass spectrometry (LC-Q-TOF/MS) showed that the unknown compound had the formula C18H27Cl2N. To elucidate the structure of this new sibutramine analogue, the target compound in the slimming formula was isolated on a preparative-LC system equipped with a PDA. After analysis by fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopy, the unknown compound was identified as a sibutramine analogue in which the iso-butyl group on the side chain is replaced with an iso-pentyl group. This new sibutramine analogue was identified to be 1-(1-(3,4-dichlorophenyl)cyclobutyl)-N,N,4-trimethylpentan-1-amine and has been named as chlorosipentramine.

Identification and structural elucidation of a new sildenafil analogue, dithiopropylcarbodenafil, from a premixed powder intended as a dietary supplement.

A new sildenafil analogue was detected during the monitoring of a premixed powder intended as a dietary supplement. The ultraviolet (UV) spectrum of the unknown compound was similar to that of dithiodesmethylcarbodenafil and dithiodesethylcarbodenafil, although their corresponding HPLC peaks were observed at different retention times. The chemical structure of the unknown compound was characterized by liquid chromatography-quadrupole-time-of-flight mass spectrometry (LC-Q-TOF/MS), followed by nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy. The comparison of its structure with that of dithiodesmethylcarbodenafil, revealed that the N-methyl group on the piperazine ring is replaced by a propyl group. This new sildenafil analogue was identified as 5-(2-ethoxy-5-(4-propylpiperazine-1-carbonothioyl)phenyl)-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo[4,3-d]pyrimidine-7-thione and designated as a dithiopropylcarbodenafil. To the best of our knowledge, this is the first study reporting the identification and characterization of dithiopropylcarbodenafil.

Monitoring of the amphetamine-like substances in dietary supplements by LC-PDA and LC-MS/MS.

Recently, amphetamine-like substances derived from the ß-phenylethylamine core structure have been detected in dietary supplements. Especially, ß-methylphenylethylamine (BMPEA), an amphetamine isomer, has been found in dietary supplements labeled as containing Acacia rigidula. The U. S. Food and Drug Administration determined that BMPEA is not naturally present in food and does not meet the statutory definition of a dietary ingredient. In addition, BMPEA has been classified as a psychotropic drug in South Korea and a doping substance by the World Anti-Doping Agency. The aim of this study was to determine whether dietary supplements contained amphetamine and amphetamine-like substance, including ß-phenylethylamine (ß-PEA) and BMPEA using LC-PDA and LC-MS/MS. In 10 of 110 samples, illegally added compounds were detected in the following ranges; ß-PEA 1.4-122.0 mg/g and BMPEA 4.7-37.6 mg/g. This study will contribute to enhancement of food safety in the South Korea.

Survey of polycyclic aromatic hydrocarbons in marine products in Korea using GC/MS.

This study investigates polycyclic aromatic hydrocarbons (PAHs) in marine products on the Korean market. A total of 280 samples of fish (n = 100), shellfish (n = 80), cephalopod (n = 60) and crustacea (n = 40) were collected for analyses of PAHs (naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3-c,d]pyrene, dibenz[a,h]anthracene and benzo[g,h,i]perylene). The analytical procedure was based on the matrix solid-phase dispersion on Florisil cartridges and extraction with hexane/dichloromethane (3:1, v/v). The PAHs were determined by gas chromatography with mass spectrometric detection using selective ion monitoring. Average recoveries for all the PAHs studied were in the range 58-79%. The sum of 16 PAHs concentrations in fish, shellfish, cephalopod/crustacea were in the range 0.2-0.5, 1.2-1.6 and 0.8-1.9 µg/kg, respectively.

Simultaneous determination of anti-diabetes/anti-obesity drugs by LC/PDA, and targeted analysis of sibutramine analog in dietary supplements by LC/MS/MS.

The safety of dietary supplements is questionable as there have been occasional reports of products contaminated with illegal adulterants. The present study was carried out to develop trustworthy methodologies to screen for six anti-diabetic drugs (phenformin, rosiglitazone, glipizide, glimepiride, glybenclamide and gliclazide) and six anti-obesity drugs (ephedrine, fenfluramine, T3, T4, fluoxetine and sibutramine) in dietary supplements. A simultaneous determination method of the 12 drugs by liquid chromatography coupled with a photodiode array (LC/PDA) was established and was validated for linearity (r(2) > 0.99), precision (RSD <13.3%), recoveries (88.8-115.9%) and reproducibility. Sibutramine and its analogs, N-desmethylsibutramine, were subject to further investigation by LC/MS/MS because they were one of the major illegal adulterants. Our proposed method to monitor illegal drug adulterations in dietary supplements using LC/PDA is a simple and reliable, and therefore applicable to routine drug-adulteration screening.