• Analytical Science and Technology
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• v.13 no.4
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• pp.484-493
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• 2000

The simultaneous analysis of alkylphenols, chlorophenols and bisphenol A in biota samples was performed by gas chromatography-mass spectrometry-selected ion monitoring mode. The phenols were extracted from sample with organic solvent and Forisil and Silica columns for clean-up procedure were compared. Recovery studies were performed at 1-ppm level of phenols added to each biota sample. Their recoveries ranged between 83 and 116% with coefficient of variations of 2.4-11.9%. To improve the detection limits of phenols, trimethylsilyl (TMS) derivatization was applied. The gas chromatographic properties of free phenols and TMS derivatized phenols were also investigated.

• Journal of Applied Biological Chemistry
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• v.59 no.2
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• pp.165-169
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• 2016

The quantitative analytical method for the bioactive substance, 3-cyano-4-methoxy-N-methyl-2-pyridone (ricinine) and an index compound, ricinoleic acid in castor plant (Ricinus communis) extract or oil was developed. For the determination of a pyridone alkaloid compound, ricinine, successive cartridge cleanup method combined with ultra-performance liquid chromatography was set up with $ENVI-Carb^{TM}$ (0.5 g) and $C_{18}$ SPE cartridges. Accuracy and precision were evaluated through fortification studies of one biopesticide (PE) at 10 and $100mg\;kg^{-1}$. Mean recoveries of ricinine were 98.7 and 96.0 % associated with less than 10 % RSD, respectively. For the determination of ricinoleic acid in castor extract and oil, saponification and methylation were optimized using gas chromatography-time of flight mass spectrometry. Recovery was more than 84.8 % associated with 6.2 % RSD after derivatization procedure. Both methodologies developed were applied to analyze real samples including three castor oil products and six commercially available biopesticides containing R. communis, collected at Korean market. The contents of ricinine and ricinoleic acid in most commercial biopesticides were less than the oil or extract contents indicated by label.

• Journal of Animal Science and Technology
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• v.61 no.3
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• pp.138-146
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• 2019

Vitamin $B_3$ (niacin) is essential for all living cells and plays a central role in energy metabolism and oxidative phosphorylation. Vitamin $B_3$, a water-soluble vitamin, is present in the form of nicotinic acid and nicotinamide, a monocarboxylic acid derivative of pyridine. While nicotinic acid is commonly effective in lowering cholesterol levels, unlike nicotinic acid, nicotinamide is ineffective on lipids. Presence rates of nicotinic acid and nicotinamide, which are the available forms of vitamin $B_3$, are different for each food. However, the studies in the literature are generally based on the analysis of total amount of vitamin $B_3$ in foods and the studies determining the profile of vitamin $B_3$ in foods are limited. The aim of the study was to determine the vitamin $B_3$ profiles of 10 kinds of animal based food and 10 different plant based food samples. In this study, 10 kinds of animal based food samples consisting of veal (veal steak fillet), chicken (breast), turkey meat (thigh), goat meat (leg, belly), lamb (leg, back, arm), mutton (belly), bovine meat (loin) and 10 different plant based food samples namely; barley, rye, wheat (bread), wheat (durum), oat, rice, dried pea, green lentil, red lentil and chickpea were studied by high performance liquid chromatography using post-column derivatization system. The presence rates of nicotinic acid and nicotinamide were determined in the meat samples as 30% and 70% and as 87% and 13% in the cereal and legume samples, respectively. Nicotinic acid levels were found in low amounts in the meat samples. The amounts of nicotinic acid in the cereal and legume samples were significantly higher than the meat samples. Consequently, the plant based foods such as cereals and legumes, with a ratio of 87% nicotinic acid presence, standout as the best source of nicotinic acid and encouraging regular intake of those cereals and legumes containing rich nicotinic acid would remove nicotinic acid deficiency in human.

• Mass Spectrometry Letters
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• v.10 no.2
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• pp.43-49
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• 2019

The aim of this study was conducted to develop an analytical method to determine the concentration of ceftiofur residue in eel, flatfish, and shrimp. For derivatization and extraction, the sample was hydrolyzed with dithioerythritol to produce desfuroylceftiofur, which was then derivatized by iodoacetamide to obtain desfuroylceftiofur acetamide. For purification, the process of solid phase extraction (Oasis HLB) was used. The target analytes were confirmed and quantified in $C_{18}$ column using liquid chromatography-tandem mass spectrometry with 0.1% formic acid in water (A) and 0.1% formic acid in acetonitrile (B) as the mobile phase. The linearity of the standard calibration curve was confirmed by a correlation coefficient, $r^2>0.99$. The limit of quantification for ceftiofur was 0.002 mg/kg; the accuracy (expressed as the average recoveries) was 80.6-105%; the precision (expressed as the coefficient of variation) was below 6.3% at 0.015, 0.03, and 0.06 mg/kg. The validated method demonstrated high accuracy and acceptable sensitivity to meet the Codex guideline requirements. The developed method was tested using market samples. As a results, ceftiofur was detected in one sample. Therefore, it can be applied to the analysis of ceftiofur residues in fishery products.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.2
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• pp.218-223
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• 2022

Cholesterol is an essential component for maintaining health; however, excessive consumption can lead to diseases. Thus, continuous monitoring of cholesterol content is important in food research. The cholesterol analysis method used in Korea follows the Korean Food Standards Codex. As this method uses gas chromatography, derivatization of the sample is required, and analysis time is more than 30 min. Kim developed a new method using liquid chromatography; however saponification by the non-heat saponification method is insufficient. To address these limitations, a new cholesterol analysis method was developed and verified. The correlation coefficients for the cholesterol standard (STD) were maintained above 0.99. The limit of detection and limit of quantitation of cholesterol STD were 2.41 ㎍/mL and 7.31 ㎍/mL, respectively. The accuracies for cholesterol were 92.21-99.02%. The developed analytical method was also verified using three standard reference materials, and their accuracies were 93.71-97.09%. In addition, the cholesterol content of fishes was analyzed, and the values were compared with those recorded by the United States Department of Agriculture. Our results suggest that this method could be used as a new analytical method for cholesterol in seafood.

• Analytical Science and Technology
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• v.35 no.6
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• pp.229-236
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• 2022

Lipidomic analyses of transient breast milk are far more limited than those of other dairy products. As a preliminary analysis of breast milk lipidomes, analytical methods for polar and nonpolar lipids from transient breast milk were developed, and detailed fatty acid profiles were determined in this study. The newly developed methods include solvent fractionation of phospholipids and acyl glycerol, one-pot derivatization to FAMEs and pyridylcarbinol esters, and instrumental analysis, including GC-FID and GC-MS. The results indicate that breast milk contains 16 major common fatty acids with 8-22 carbons. Additionally, 29 minor fatty acids were identified, including odd-numbered fatty acids and branched analogues with 11-23 carbons. Their detailed concentrations in different fractions were measured using the internal standard method. In addition to ordinary fatty acids, breast milk contains several branched fatty acids, including iso/anteiso acids with 15-18 carbons. Structural studies have been performed on selected minor fatty acids via chemical synthesis.

• Analytical Science and Technology
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• v.20 no.5
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• pp.400-405
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• 2007

The comparative analysis of glycerin in cosmetic samples was carried out by LC/MS and $^1H$ NMR spectrometry. For the LC/MS analysis, aqueous solution was controlled in strong basic condition with sodium hydroxide, and benzoyl chloride was added to the solution for the derivatization of glycerin. The derivative was extracted using pentane and analyzed by the LC/MS. For the $^1H$ NMR analysis, sample was directly dissolved in $D_2O$ solvent without pretreatment. The quantitative analysis of glycerin was done by $^1H$ NMR ERETIC method. The analysis results of LC/MS and $^1H$ NMR showed that the calibration curves were a good linearity with $r^2=0.9991$ in the range of 0.1 to $10{\mu}g/mL$ and $r^2=1$ in the range of 25 to $500{\mu}g/mL$, respectively.

• Analytical Science and Technology
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• v.20 no.3
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• pp.198-203
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• 2007

The analysis method of 3-Monochloropropane-1,2-diol (3-MCPD) compound in water was developed using liquid chromatography with mass spectrometric detection. Aqueous solution was controlled in strong basic condition with sodium hydroxide, and then $25{\mu}L$ of benzoyl chloride was added to the solution for the derivatization of 3-MCPD. The derivative was extracted using pentane and analyzed by the selected ion monitoring (SIM) method of LC-MS. The results of analyses showed that the calibration curves was in the range of 1.0 to $100{\mu}g/mL$ with a good linearity (correlation coefficient of $r^2=0.992$) and limit of detection was below $0.01{\mu}g/mL$. The recoveries of this analysis method by LC-MS were 92.3-98.0 %.

• Journal of Food Hygiene and Safety
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• v.35 no.3
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• pp.225-233
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• 2020

By the standards and specifications for hygiene products, three test methods for formaldehyde are specified for each item type of hygiene product. After derivatization using acetylacetone and 2,4-dinitrophenylhydrazine (2,4-DNPH), formaldehyde is analyzed by spectrophotometer and high-performance liquid chromatography (HPLC). Validation of the three test methods was performed on tissue, diaper lining and waterproof layer, and panty liner products. The results of linearity (R²), limit of detection (LOD), limit of quantification (LOQ), recovery rate (%) and reproducibility (%), showed that all three methods are suitable for analyzing formaldehyde in hygiene products. After derivatization with 2,4-DNPH and cetylacetone, formaldehyde was analyzed at 0, 3, 6, 9, 24 and 48 hours by HPLC. Formaldehyde derivatized with 2,4-DNPH showed no statistically significant change in formaldehyde peak area over time (P>0.05). But, acetylacetone-derivatizated formaldehyde showed a negative correlation coefficient (r) over time (P<0.01). We investigated the residual amounts of formaldehyde in 205 hygiene products distributed in Busan. Among 74 disposable diaper products tested, 73 had low concentrations of formaldehyde (0.13-29.87 mg/kg). Moreover, formaldehyde was not detected in any of 78 tissue, 27 disposable paper towel, 12 disposable dishcloth, 7 paper cup, one brand of paper straw and 6 disposable napkin products.

• Journal of Food Hygiene and Safety
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• v.31 no.2
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• pp.85-93
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• 2016

A rapid method using HPLC-MS/MS has been developed for quantitative determination of the metabolites of nitrofurans, namely 3-amino-2-oxazolidone (AOZ), 5-morpholinomethyl-3-amino-2-oxazolidinone (AMOZ), 1-ammino-hydantoin (AHD) and semicarbazide (SEM) in loach. The extraction procedure was founded on simultaneous acidic hydrolysis and derivatization using 2-nitrobenzaldehyde (2-NBA) for 1 hour at $50^{\circ}C$, followed by purification with liquid-liquid extraction. Recovery was evaluated by spiking standards into blank samples at three levels (0.5, 1.0 and $2.0{\mu}g/kg$), and the mean recovery was 75.1-108.1%. Precision values expressed as the relative standard deviation (%RSD) were ${\leq}8.7%$ and ${\leq}8.5%$ for intra-day and inter-day precision, respectively. Linearity was studied in the range of $0.2-20{\mu}g/Kg$ for NBAOZ, $0.8-20{\mu}g/Kg$ for NBAMOZ, $0.2-20{\mu}g/Kg$ for NBAHD, and $0.1-20{\mu}g/Kg$ for NBSEM, and the obtained coefficient correlations (r) were ${\geq}0.99$ for all compounds. Limits of detection (LODs) for the derivatized nitrofuran metabolites were established at $0.06{\mu}g/Kg$ for NBAOZ, $0.24{\mu}g/Kg$ for NBAMOZ, $0.06{\mu}g/Kg$ for NBAHD, and $0.03{\mu}g/Kg$ for NBSEM. Limits of quantification (LOQs) were established at $0.2{\mu}g/Kg$ for NBAOZ, $0.8{\mu}g/Kg$ for NBAMOZ, $0.2{\mu}g/Kg$ for NBAHD, and $0.1{\mu}g/Kg$ for NBSEM. This simplified rapid method for reducing the derivatization and hydrolysis times can be applied to the determination of nitro-furan residues in loach.