Determination of Residual Triflumezopyrim Insecticide in Agricultural Products through a Modified QuEChERS Method.

A rapid and simple analytical method for triflumezopyrim, a new class of mesoionic insecticides and commercialized molecules from DuPont, was developed with a modified QuEChERS method. The pH adjustment was used to improve the extraction efficiency of acetonitrile solvent, and dispersive solid-phase extraction was employed for the clean-up process. The five selected food commodities were used to verify the present optimized method, which displayed good linearity with an excellent correlation coefficient (R2 = 0.9992-0.9998) in the 0.003-0.30 mg/kg calibration range. The method limits of detection (LOD) and quantification (LOQ) were determined to be a value of 0.003 and 0.01 mg/kg, respectively. The mean recovery for the triflumezopyrim was in the 89.7-104.3% range. The relative standard deviations were ≤9.8% for intra- (n = 5) and inter-day (n = 15) precisions at concentrations of 0.01, 0.1, and 0.5 mg/kg in the five representative samples. The matrix effect has been calculated to confirm the effect during ionization of the analyte in the UPLC-MS/MS. The matrix effects of the instrumental analysis showed that triflumezopyrim was less susceptible to matrices. The proposed analytical method in this study has effectively improved the accuracy, selectivity, and sensitivity for the determination of triflumezopyrim in agricultural commodities; therefore, it can serve as a reference method for the establishment of maximum residue limits (MRLs).

Safety assessment of antioxidants and color fixatives for the Korean population using dietary intake monitoring.

Food additives such as antioxidants and color fixatives are substances used in food intentionally for technical effect, such as decolorizing or intensifying the color of food. Based on the necessity of re-evaluating food additives for safety and to improve consumer perception, we conducted safety assessments for food additives according to the Risk Assessment Guidelines of the Korean Ministry of Food and Drug Safety. These safety assessments evaluated new risk information based on toxicology data and estimates of dietary intake exposures to food additives in comparison with the acceptable daily intake (ADI). Estimated daily intakes (EDI) of food additives were calculated using food consumption data for the Korean population derived from the Korea National Health and Nutrition Examination Survey and monitoring data based on the analysis of food additives in food products. Unlike contaminants, antioxidants and color fixatives are purposely added as food additives, and they are largely consumed in processed foods. Therefore, EDI was compared with ADI to investigate the likelihood of potentially hazardous effects in humans. The risk likelihoods of food additives, evaluated by comparing the EDI with the ADI, were less than 2% in the total population. Thus, exposure levels to antioxidants and color fixatives do not exceed the ADI. Based on the safety assessments conducted in this study, we estimate exposure to food additives to be within safe limits for all population groups.

Naturally occurring benzoic, sorbic, and propionic acid in vegetables.

Benzoic, sorbic and propionic acid are used as preservatives in foods and can also be naturally present in processed foods. The levels of preservatives in 939 vegetables were determined. Benzoic and sorbic acid were analysed by high-performance liquid chromatography with a diode-array detector and further confirmed by liquid chromatography-tandem mass spectrometry, whereas propionic acid was analysed using a gas chromatography-flame ionization detector and further confirmed by gas chromatography-mass spectrometry. Benzoic and propionic acid were found in 10.9% and 36.2%, respectively, of the samples. In contrast, sorbic acid was not found in any of the samples. The highest amounts of benzoic and propionic acid were found in perilla leaves (0.33-298 mg kg-1) and ginseng (

Simultaneous determination of sodium iron chlorophyllin and sodium copper chlorophyllin in food using high-performance liquid chromatography and ultra-performance liquid chromatography-mass spectrometry.

A simultaneous method for analyzing sodium iron chlorophyllin (SIC) and sodium copper chlorophyllin (SCC) using high-performance liquid chromatography was developed. This method employed an Inertsil ODS-2 column and diode array detection at 395 nm, using methanol-water (97:3 and 80:20, v/v) containing 1% acetic acid as the mobile phase. Liquid chromatography-tandem mass spectrometry was used to identify the main components of SIC and SCC as Fe-isochlorine e4 and Cu-isochlorine e4, respectively. The limits of detection and quantitation of SIC were 1.2 and 4.1 mg/kg, respectively, while those of SCC were 1.4 and 4.8 mg/kg, respectively. For intraday and interday tests, the SIC recoveries from candy ranged from 81% to 101%, while SCC recoveries ranged from 100% to 109%. The developed method can be applied to the rapid determination of SIC and SCC in candy.

Improved method for the determination of 12 non-nutritive sweeteners and monitoring in various foods using liquid chromatography-tandem mass spectrometry.

An improved and highly sensitive method was developed and validated for the determination of 12 (7 permitted and 5 non-permitted in Korea) non-nutritive sweeteners in various foods using liquid chromatography-electrospray ionisation-tandem mass spectrometry. The chromatographic separation was performed on an Xbridge BEH C18 column (3 mm × 100 mm, 2.5 µm) with gradient elution using 10 mM ammonium acetate in water and 10 mM ammonium acetate in methanol. Sample preparation consisted of simple dilution, homogenisation, centrifugation and purification with a C18 cartridge prior to analysis. The relative matrix effect (%ME) was within ±20% for all sweeteners. The method also showed good linearity (R2 > 0.99). The limit of detection and limit of quantification values in sample were in the range of 0.02-2.66 and 0.06-8.05 mg kg-1, respectively. The recoveries at three concentration levels ranged between 80% and 119%, with relative standard deviation values below 10%. In addition, the expanded uncertainties determined for 12 sweeteners in 5 different food matrices were confirmed to be <14%. Finally, the method was successfully applied to the analysis of sweeteners in 681 food samples purchased in Korea, Australia and Turkey. These results demonstrate that the method is suitable for the simultaneous determination of multiple-sweeteners in a variety of foods.

Sorbic, benzoic and propionic acids in fishery products: a survey of the South Korean market.

This study was conducted to provide basic data as part of a project to distinguish naturally occurring organic acids from added preservatives. Accordingly, we investigated naturally occurring levels of sorbic, benzoic and propionic acids in fish and their processed commodities. The levels of sorbic, benzoic and propionic acids in 265 fish and their processed commodities were determined by high-performance liquid chromatography-photodiode detection array (HPLC-PDA) of sorbic and benzoic acids and gas chromatography-mass spectrometry (GC/MS) of propionic acid. For propionic acid, GC-MS was used because of its high sensitivity and selectivity in complicated matrix samples. Propionic acid was detected in 36.6% of fish samples and 50.4% of processed fish commodities. In contrast, benzoic acid was detected in 5.6% of fish samples, and sorbic acid was not detected in any sample. According to the Korean Food and Drug Administration (KFDA), fishery products and salted fish may only contain sorbic acid in amounts up to 2.0 g kg-1 and 1.0 g kg-1, respectively. The results of the monitoring in this study can be considered violations of KFDA regulations (total 124; benzoic acid 8, propionic acid 116). However, it is difficult to distinguish naturally generated organic acids and artificially added preservatives in fishery products. Therefore, further studies are needed to extend the database for distinction of naturally generated organic acids and added preservatives.

Identifying method validation and measurement uncertainty of brominated vegetable oil in soft drinks and carbonated waters commonly consumed in South Korea.

This study investigated a method for validating and determining the measurement uncertainty for the composition of brominated vegetable oil (BVO) in soft drinks and carbonated waters commonly consumed in South Korea. First, we studied a simple and precise qualitative colorimetric method at the maximum residues level 15 ppm. And an analytical method using ion chromatography (IC) was validated and identified with brominated fatty acids by gas chromatography electron ionization mass spectrometry (GC/EI-MS). The measurement uncertainty was evaluated based on the precisional study and confirmed by the preliminary inter-laboratory study. For IC analysis, the recovery range of BVO was from 97.8% to 107.2% with relative standard deviations between 0.18% and 0.69%. In addition, the expanded uncertainty of the BVO was 1.59. These results indicate that the validated method is appropriate for identifying of BVO and can be used to verify the safety of soft drinks or carbonated waters containing BVO residues.

Safety assessment of 16 sweeteners for the Korean population using dietary intake monitoring and poundage method.

A sweetener is a food additive that imparts a sweet taste to food products. Sweeteners have been increasingly used in Korea since the approval of sodium saccharin and d-sorbitol in 1962. Unlike food contaminants, humans are exposed to food additives only through the consumption of processed food products. For exposure assessments of sweeteners, the dietary intakes of food products containing acesulfame-K, aspartame, saccharin-Na, and sucralose were determined, and the resulting calculated estimated daily intake (EDI) values were compared directly with each additive's ADI. The poundage method was used to calculate the daily intake per capita for 12 additional sweeteners, such as lactitol, for which appropriate analytical methods for food products do not exist. The risk, as evaluated by comparing the EDI with the ADI, was determined to be 2.9% for acesulfame-K, 0.8% for aspartame, 3.6% for saccharin-Na, 4.3% for steviol glycosides, and 2.1% for sucralose. No hazardous effect was predicted for the other 11 sweeteners, including lactitol.

Perception Gaps on Food Additives among Various Groups in Korea: Food Experts, Teachers, Nutrition Teachers, Nongovernmental Organization Members, and General Consumers.

The purpose of this study was to determine the perceptions and information needs of food experts, teachers, nutrition teachers, members of nongovernmental organizations, and general consumers concerning food additives. Questions in a survey format included perceptions, information needs, and preferred communication channels. The survey was conducted both off-line and on-line via e-mail and Google Drive in March 2015. The results indicated that most Korean consumers are concerned about the safety of using food additives in processed foods and do not recognize these additives as safe and useful materials as part of a modern diet. We also identified perception gaps among different groups regarding food additives. Nutrition teachers and members of nongovernmental organizations in Korea appeared to have a biased perception of food additives, which may cause general consumers to have a negative perception of food additives. The group of food experts did not have this bias. Governmental institutions must overcome the low confidence levels of various groups as an information provider about food additives. Based on the findings in this study, it will be possible to develop a strategy for risk communication about food additives for each group.

Simultaneous determination of sodium saccharin, aspartame, acesulfame-K and sucralose in food consumed in Korea using high-performance liquid chromatography and evaporative light-scattering detection.

Four artificial sweeteners, i.e., sodium saccharin, aspartame, acesulfame-K and sucralose, are permitted for use in Korea, and recent regulatory changes have expanded the number of food categories in which they may be used. Four artificial sweeteners were determined simultaneously in more than 900 food items from 30 food categories that are commercially available in Korean markets, including both domestic and imported products, using high-performance liquid chromatography and evaporative light-scattering detection (ELSD). A new procedure using 75% acetone to remove fat was applied for sample preparation. The levels detected in all samples were below the maximum permitted use levels established in Korea. Despite the increased number of categories, the only one in which sodium saccharin was newly found was takju, an alcoholic beverage. Sodium saccharin was not found in other beverages in the food analysis or in the food label survey, even though its use was reported in a previous study, suggesting that consumer preference outweighs regulatory decisions. When the analytical results were combined with food-consumption data obtained from the Korea National Health and Nutrition Examination Survey 2010-14, the estimated daily intakes of all the sweeteners were considered safe.

An analysis method for determining residual hexane in health functional food products using static headspace gas chromatography.

A method for analyzing the contents of residual hexane in health functional food products was developed. The dissolving solvents in the health functional food products and the internal standard selected were N,N-dimethylacetamide and heptane, respectively. The analysis conditions for headspace-gas chromatography/flame ionization detection (HS-GC/FID) and headspace-gas chromatography/mass spectrometry (HS-GC/MS) were determined as 18 mL of headspace volume, 100°C of headspace oven temperature, and 30 min of equilibration time; a Durabond (DB)-624 column was selected for this analysis. To validate this method, which applies N,N-dimethylacetamide as a dissolving solvent, the limit of detection and limit of quantification (LOQ) values based on the HS-GC/FID and HS-GC/MS analyses results were found to be 0.10, 0.29 and 0.16, 0.47 mg/L, respectively. The recoveries and coefficient of variation (CV) obtained by HS-GC/MS were 96.39-119.86% and 0.04-1.25%, respectively, better than those obtained by HS-GC/FID. By applying the HS-GC/MS method, it was possible to analyze the content of the residual hexane in 60 different types of health functional food products.

Assessment of the dietary intake of propylene glycol in the Korean population.

An improved method for the analysis of propylene glycol (PG) in foods using a gas chromatography-flame ionisation detector (GC-FID), with confirmation by GC-MS, was validated by measuring several analytical parameters. The PG concentrations in 1073 products available in Korean markets were determined. PG was detected in 74.1% of the samples, in a concentration range from the limit of detection (n.d., 0.39 µg ml(-1)) to 12,819.9 mg kg(-1). The Korea National Health and Nutrition Examination Survey (KNHANES) 2011-2013 reported the mean intake levels of PG from all sources by the general population and consumers were 26.3 mg day(-1) (0.52 mg kg(-1) day(-1)) and 34.3 mg day(-1) (0.67 mg kg(-1) day(-1)), respectively. The 95th percentile intake levels of the general population and consumers were 123.6 mg day(-1) (2.39 mg kg(-1) day(-1)) and 146.3 mg day(-1) (2.86 mg kg(-1) day(-1)), respectively. In all groups of the general population, breads were the main contributors to the total PG intake. These reports provide a current perspective on the daily intake of PG in the Korean population.

Voltage-dependent ion channel currents in putative neuroendocrine cells dissociated from the ventral prostate of rat.

Prostate neuroendocrine (NE) cells play important roles in the growth and differentiation of the prostate. Following enzymatic digestion of rat ventral prostate, the whole-cell patch-clamp technique was applied to dark, round cells that exhibited chromogranin-A immunoreactivity, a representative marker of NE cells. Under zero current-clamp conditions, putative NE cells showed hyperpolarized resting membrane potentials of some -70 mV, and spontaneous action potentials were induced by an increase in external [K+] or by the injection of current. Using a CsCl pipette solution, step-like depolarization activated high-voltage-activated Ca2+ current (HVA I(Ca)) and tetrodotoxin-resistant voltage-activated Na+ current. The HVA I(Ca) was blocked by nifedipine and omega-conotoxin GVIA, L-type and N-type Ca2+ channel blockers, respectively. Using a KCl pipette solution, the transient outward K+ current (I(to)), Ca2+ -activated K+ currents (I(K,Ca)), the non-inactivating outward current and an inwardly rectifying K+ current (I(Kir)) were identified. I(K,Ca) was suppressed by charybdotoxin (50 nM), iberiotoxin (10 nM) or clotrimazol (1 microM), but not by apamine (100 nM). I(to) was inhibited by 4-aminopyridine (5 mM). I(Kir) was identified as a Ba2+ -sensitive inwardly rectifying current in the presence of a high-K+ bath solution. The voltage- and Ca2+ -activated ion channels could play significant roles in the regulation of neurohormonal secretion in the prostate.