• Analytical Science and Technology
• /
• v.25 no.2
• /
• pp.121-126
• /
• 2012

It is essential to evaluate the quality of Hanji record paper without damaging the record paper by previous destructive methods. The samples were Hanji record paper produced in the 1900s. Near-infrared (NIR) spectrometer was used as a non destructive method for evaluating the quality of record papers. Fourier transform (FT) spectrometer was used with 12,500 to 4,000 $cm^{-1}$ wavenumber range for quantitative analysis and it has high accuracy and good signal-to-noise ratio. The acidity and moisture content of Hanji record paper were measured by integrating sphere as diffuse reflectance type. The acidity (pH) of chemical factors as a quality evaluated factor of Hanji was correlated to NIR spectrum. The NIR spectrum was pretreated to obtain the coefficients of optimum correlation. Multiplicative scatter correction (MSC) and First derivative of Savitzky-Golay were used as pretreated methods. The coefficients of optimum correlation were calculated by PLSR (partial least square regression). The correlation coefficients ($R^2$) of acidity had 0.92 on NIR spectra without pretreatment. Also the standard error of prediction (SEP) of pH was 0.24. And then the NIR spectra with pretreatment would have better correlation coefficient ($R^2$ = 0.98) and 0.19 as SEP on pH. For moisture contents, the linearity correlation without pretreatment was higher than the case with pretreatment (MSC, $1^{st}$ derivative). As the best result, the $R^2$ was 0.99 and SEP was 0.45. This indicates that it is highly proper to evaluate the quality of Hanji record papers speedily with integrated sphere and FT NIR analyzer as a non-destructive method.

• The Korean Journal of Pesticide Science
• /
• v.19 no.1
• /
• pp.5-13
• /
• 2015

A chromatographic method for the determination of imazapyr, a non-selective herbicide, in agricultural commodities was developed to use safety control of pesticide residue on crops, and was fully validated as an official method for residue analysis. Agricultural commodities, mandarin (fruit), hulled rice (cereal grains), pepper (vegetables), potato (potatoes) and soybean (beans) were extracted with methanol and partitioned with dichloromethane to remove the interference obtained from sample extracts, adjusting pH to 2.5 by 4N hydrochloric acid. Finally, they were analyzed by high performance liquid chromatography coupled to UV detector (HPLC-UVD). The developed method had the linearity in the range of test concentrations with coefficients of determination ($r^2$) more than 0.99. Recovery studies were carried out at three concentration levels (LOQ, 10LOQ, and 50LOQ) performing five replicates at each level. Recoveries were ranged between 72.1 to 108.0%, with relative standard deviations less than 10%. A consistent recovery was determined according to the CODEX guidelines (CAC/GL40, 2003). Finally, LC/MS with selected ion monitoring was also applied to confirm the suspected residues of imazapyr in agricultural samples. This developed method for determination of imazapyr residues in agricultural commodities. can be used as an official method.

• Journal of Food Hygiene and Safety
• /
• v.19 no.1
• /
• pp.12-18
• /
• 2004

Ofloxacin, norfloxacin, ciprofloxacin, and enrofloxacin in chicken muscle were seperated by liquid extraction and determined with high performance liquid chromatography (HPLC) with fluorescence detector. Analysis was carried out using following conditions; Cl8 column (250${\times}$4.6 mm i.d. 5 ${\mu}{\textrm}{m}$ particle size), mobile phase composed of D.W. (containing 0.4% triethylamine and phospholic acid): methanol : acetonitrile (800:100:100, v/v/v), isocratic pump at a flow rate of 1.0 $m\ell$/min and 50 ${mu}ell$ of injection volume, fluorescence detector with EX278 nm/EM.456 nm. The calibration curves of four fluoroquinolones showed linearity (${\gamma}$$^2$$\geq$0.999) at concenration range of 0.025-0.6 $\mu\textrm{g}$/ml. The recoveries in fortified chicken muscle represented more than 80% with low coefficient of variation (〈10%) for concentration range of four fluoroquinolones. The detection limits for ofloxacin, norfloxacin, ciprofloxacin, and enrofloxacin were 23.5, 3.4, 3.0 and 2.5 ng/g in chicken muscle, respectively. We also monitored fluoroquinolones residue in muscle of chickens (broiler 1:227, Korean native chicken 219, laying chicken 77) using EEC-4-plate screening and HPLC conformation methods. Ten(broiler 5, Korean native chicken 5) out of the fifteen samples which were positively detected by EEC-plate screening method from 1,523 chicken meat were confirmed with ciprofloxacin and enrofloxacin by HPLC. The ranges of residual concentration were 0-0.12 ppm for ciprofloxacin and 0.01-6.79 ppm for enrofloxacin. In conclusion, our method could be applied effectively to determine four fluoroquinolones residues in chicken meat, and further survey for fluoroquinolones residue in chicken meat are needed for more effective control of fluoroquinolones used in livestock.

• Journal of Food Hygiene and Safety
• /
• v.33 no.2
• /
• pp.124-130
• /
• 2018

The Ministry of Food and Drug Safety (MFDS) is amending its test methods for the use of health functional foods (dietary food supplement), in order to establish regulatory standards and specifications in Korea. In this regard, we continue to pursue and perform our research on the analytical method development for the items being researched and reviewed. In this study, we have developed a sensitive and selective test method that could simultaneously separate and determinate six major bioactive flavonolignans in silymarin, which are based on the use of a liquid chromatographic-tandem mass spectrometry (LC-MS/MS). The standard calibration curves presented a linearity effect with the correlation coefficient ($r^2$) > 0.999. The limits of detection (LODs) and limits of quantitation (LOQs) were in the range of $0.3{\sim}9.0{\mu}g/L$ and $0.8{\sim}27.3{\mu}g/L$, respectively. The recovery results ranged between 96.2~98.6% at 3 different concentration levels, and its relative standard deviations (RSDs) were less than 5% as noted in this study. The proposed analytical method was characterized with a noted high resolution of the individual silymarin constituents, and the assay was fully validated as well. Our research can provide a significant scientific evidence that can be useful to amend the silymarin test method for the Health Functional Food Code.

• Food Engineering Progress
• /
• v.13 no.3
• /
• pp.195-202
• /
• 2009

This study was accomplished that analysis of seven polycyclic aromatic hydrocarbons (PAHs) in smoked or nonsmoked processing foods by high performance liquid chromatography (HPLC) with fluorescence detection. The calibration line was constructed with injected different levels of standard concentration. Limit of detection (LOD) and limit of quantification(LOQ) showed higher linearity ($r^{2}$=0.998) reasonably, and recovery exhibited 0.033-0.666 $\mu$g/kg, 0.108-2.217 $\mu$g/kg and 69.31-90.14%, respectively. As a result, the samples using smoked tuna as smoked materials contained seven PAHs with different range from 0.256 to 0.486 $\mu$g/kg. The benzo[a]pyrene, indicator of PAHs, was detected to below the LOQ in two samples. Concentrations of benzo[a]pyrene in three samples were below the 2 $\mu$g/kg which is the limit of regulation. Smoked tuna sauces were detected from 0.321 to 0.552 $\mu$g/kg and not detected in drying powders. PAHs of smoked meat products were ranged from 0.720 to 2.027 $\mu$g/kg and are higher than concentration of tuna smoked samples. PAHs were very low in non-smoked foods including mustard, herb, and roasted meats.

• Journal of Food Hygiene and Safety
• /
• v.34 no.5
• /
• pp.413-420
• /
• 2019

In this study, a sample preparation method and a simultaneous determination method by ultra-high performance liquid chromatography coupled with tandem mass spectrometry for 9 isomers of chlorogenic acid and arbutin in fruits were developed. The samples were extracted using 90% methanol (pH 3.0), with the solutions being shaken and then sonicated for 10 min each. After centrifugation at 4,000 rpm for 10 min, the extraction was concentrated under a vacuum at $40^{\circ}C$ using a vacuum evaporator. The residue was dissolved in 5 mL of 5% methanol and filtered through a $0.45{\mu}m$ membrane before UHPLC-MS/MS analysis. The separations were performed on a C18 column with gradient elution of water (containing 0.1% formic acid) and methanol (containing 0.1% formic acid). The specificity, linearity, limit of detection, limit of quantification, accuracy, and precision of the proposed methods were also evaluated.

• Journal of Food Hygiene and Safety
• /
• v.34 no.5
• /
• pp.454-462
• /
• 2019

A conventional Korean meal typically includes various roasted, steamed, stir-fried, and braised foods. For this study, we investigated the contents of water soluble vitamins, $B_1$ (thiamin), $B_2$ (riboflavin) and $B_3$ (niacin) in various roasted, steamed, stir-fried, and braised foods. Method validation for analytical data in this study showed a high linearity ($r^2$>0.999), and the limit of detection and quantification were 0.001-0.067 and $0.002-0.203{\mu}g/mL$, respectively. For accuracy and precision, analytical values using standard reference materials were in the certified ranges. Roasted foods contained 0.039-1.057 mg/100 g of thiamin, 0.058-0.686 mg/100 g of riboflavin and 0.021-21.772 mg/100 g of niacin. Steamed foods contained 0.049-1.066 mg/100 g of thiamin, 0.025-0.548 mg/100 g of riboflavin and 0.134-21.509 mg/100 g of niacin. Stir-fried foods contained 0.114-0.388 mg/100 g of thiamin, 0.014-1.258 mg/100 g of riboflavin and 0.015-2.319 mg/100 g of niacin. Braised foods contained 0.112-1.656 mg/100 g of thiamin, 0.024-0.298 mg/100 g of riboflavin and 0.322-2.157 mg/100 g of niacin. The data on water-soluble vitamins in this study can be used for a nutritional database of conventional Korean meals.

• Journal of Food Hygiene and Safety
• /
• v.34 no.2
• /
• pp.148-157
• /
• 2019

An optimized analytical method for sodium iron chloriphyllin in foods was established and verified by using high performance liquid chromatography with attached diode array detection. An Inertsil ODS-2 column and methanol-water (80:20 containing 1% acetate) as a mobile phase were employed. The limit of detection and quantitation of sodium iron chloriphyllin were 0.1 and 0.3 mg/kg, respectively, and the linearity of calibration curve was excellent ($R^2=0.9999$). The accuracy and precision were 93.9~104.95% and 2.0~7.7% in both inter-day and intra-day tests. Recoveries for candy and salad dressing were ranged between 93 and 104% (relative standard deviation, (RSD) 0.3~4.3%), and between 83 and 115% (RSD 1.2~2.0%), respectively. Liquid chromatography mass spectrometry was used to verify the main components of sodium iron chlorophyllin which were Fe-isochlorin e4 and Fe-chlorin e4.

• Journal of Food Hygiene and Safety
• /
• v.35 no.6
• /
• pp.544-551
• /
• 2020

The aim of this study was to develop and validate a simultaneous analytical method for berberine and palmatine, which are representative substances of Phellodendron amurense, and to evaluate the antioxidant activity. We evaluated the specificity, linearity, precision, accuracy, limit of detection (LOD), and limit of quantification (LOQ) of analytical methods for berberine and palmatine using high-performance liquid chromatography. Our result showed that the correlation coefficients of the calibration curve for berberine and palmatine exhibited 0.9999. The LODs for berberine and palmatine were 0.32 to 0.35 µg/mL and the LOQs were 0.97 to 1.06 µg/mL, respectively. The inter-day and intra-day precision values for berberine and palmatine were from 0.12 to 1.93 and 0.19 to 2.89%, respectively. The inter-day and intra-day accuracies were 98.43-101.45% and 92.39-100.60%, respectively. In addition, the simultaneous analytical method was validated for the detection of berberine and palmatine. Moreover, we conducted FRAP and NaNO2 scavenging activity assays to measure the antioxidant activities of berberine and palmatine, and both showed antioxidant activity. These results suggest that P.amurense could be a potential natural resource for antioxidant activity and that the efficacy can be confirmed by investigating the content of the berberine and palmatine.

• Journal of Food Hygiene and Safety
• /
• v.37 no.3
• /
• pp.143-148
• /
• 2022

This study was to investigate an analytical method for determining dieckol content in Ecklonia stolonifera extract. According to the guidelines of International Conference on Harmonization. Method validation was performed by measuring the specificity, linearity, precision, accuracy, limit of detection (LOD), and limit of quantification (LOQ) of dieckol using high-performance liquid chromatography-photodiode array. The results showed that the correlation coefficient of calibration curve (R²) for dieckol was 0.9997. The LOD and LOQ for dieckol were 0.18 and 0.56 ㎍/mL, respectively. The intra- and inter-day precision values of dieckol were approximately 1.58-4.39% and 1.37-4.64%, respectively. Moreover, intra- and inter-day accuracies of dieckol were approximately 96.91-102.33% and 98.41-105.71%, respectively. Thus, we successfully validated the analytical method for estimating dieckol content in E. stolonifera extract.