Analysis of ethyl glucuronide and ethyl sulfate in blood to determine the absorption or elimination phase of alcohol for Korean.

This study was conducted to understand alcohol kinetics for Koreans and to determine whether an individual is in absorption phase or elimination phase at the time of blood collection by analyzing of ethyl glucuronide and ethyl sulfate in blood. A total of 50 healthy adults was selected and assigned to drink 1g of ethanol per kg body weight of individual within 1h. Blood samples were then collected every 15min for the first 3h, 30min next 3h, and 1h last 9h. Urine samples were also collected from the individual, but not under the controlled environment. All samples were then analyzed by gas chromatography with a flame ionization detector (GC-FID) for alcohol and liquid chromatography-mass/mass spectrometry (LC-MS/MS) for EtG and EtS. The maximum BAC (Cmax) was 0.138% (g/100mL) in average under the controlled experimental condition. Alcohol elimination rates (ß) in average were 0.020% for male and 0.024% for female, respectively. It was found that the ratio of UAC and BAC was less than 1 in the absorption phase and the average ratio of UAC and BAC was 1.47 in the elimination phase. The comparison of BAC (g/L) and EtG (mg/L) absorption and elimination curves showed that the intersection time was 3.9h in average. It is shown that the ratio of EtG (mg/L)/BAC (g/L) is higher than 1, the individual would be in elimination phase of BAC. At the time of Cmax, the ratio of EtG (mg/L)/BAC (g/L) was 0.255±0.132 (SD) in average.

Discrimination of the geographic origin of pork using multi-isotopes and statistical analysis.

RATIONALE: While global pork production has grown exponentially in recent decades to 109 Mt in 2010, methods aimed at verifying the geographic origin of pork products have yet to be thoroughly investigated. Here, we analyzed pork samples available in South Korea in order to discriminate their geographic origin. METHODS: A total of the 37 pork samples originated from South Korea and other countries (Denmark, Germany, France, Spain, Canada and Mexico) were collected in order to classify their geographic origins using multi-isotope ratios, such as δ18 O, δ2 H, δ13 C, δ15 N values measured by IRMS, 87 Sr/86 Sr ratios measured by MC-ICP-MS, and multivariate statistical approaches. RESULTS: There is a wide range of 87 Sr/86 Sr ratios in the pork samples, varying from 0.70779 to 0.71245, due to the lithology where the pork was raised. Canadian samples displayed the lowest δ18 O and δ2 H values mainly due to the latitude effect. Furthermore, the δ13 C values of European and Canadian samples were lower than those of Korean and Mexican samples, depending on whether the feed was composed of either C3 or C4 plants. The δ15 N values of the European and Canadian samples were much higher than those of the other samples, possibly resulting from the δ15 N values of the feed. CONCLUSIONS: While differences in pork samples were observed that depended on geographic origin, this study suggests that more detailed investigations are needed to validate whether a combination of multi-isotope and multivariate statistical approaches is a valid method for determining the geographic origin of pork.

Discrimination of side-window glass of Korean autos by laser ablation inductively coupled plasma mass spectrometry.

RATIONALE: Fragments of glass from cars are often found at crime scenes and can be crucial evidence for solving the crime. The glass fragments are important as trace evidence at crime scenes related to car accidents and burgled homes. By identifying the origin of glass fragments, it is possible to infer the identity of a suspect. Our results represent a promising approach to a thorough forensic investigation of car glass. METHODS: Thirty-five samples from the side windows of cars produced and used in South Korea were collected from the official agencies of five car manufacturers and from two glassmakers. In addition, 120 samples from side mirrors were collected from the same suppliers as well as from small businesses. Their chemical compositions (including Pb isotopes) were analyzed using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and linear discriminant analysis (LDA) was performed. RESULTS: The percentages of major elements (Si, Ca, and Fe) in side-window glass varied within narrow ranges (30.0 ± 2.36%, 5.93 ± 0.52%, and 0.33 ± 0.05%, respectively), while the differences among Pb isotope ratios were not significant. In contrast, light rare earth elements (LREEs) were different from each glassmaker. From the LDA, the types of side-window glass were successfully discriminated according to car manufacturer, glassmaker, and even glass thickness. However, glass from side mirrors cannot be used for good forensic identifiers. CONCLUSIONS: Discrimination techniques for side-window glass, although not for side mirrors, using chemical compositions combined with multivariate statistical analyses provide evidence for forensic investigations. Copyright © 2016 John Wiley & Sons, Ltd.

Discrimination of ginseng cultivation regions using light stable isotope analysis.

Korean ginseng is considered to be a precious health food in Asia. Today, thieves frequently compromise ginseng farms by pervasive theft. Thus, studies regarding the characteristics of ginseng according to growth region are required in order to deter ginseng thieves and prevent theft. In this study, 6 regions were selected on the basis of Korea regional criteria (si, gun, gu), and two ginseng-farms were randomly selected from each of the 6 regions. Then 4-6 samples of ginseng were acquired from each ginseng farm. The stable isotopic compositions of H, O, C, and N of the collected ginseng samples were analyzed. As a result, differences in the hydrogen isotope ratios could be used to distinguish regional differences, and differences in the nitrogen isotope ratios yielded characteristic information regarding the farms from which the samples were obtained. Thus, stable isotope values could be used to differentiate samples according to regional differences. Therefore, stable isotope analysis serves as a powerful tool to discriminate the regional origin of Korean ginseng samples from across Korea.

Discrimination between ginseng from Korea and China by light stable isotope analysis.

Ginseng is a health food and traditional medicine highly valued in Asia. Ginseng from certain origins is higher valued than from other origins, so that a reliable method for differentiation of geographical origin is important for the economics of ginseng production. To discriminate between ginseng samples from South Korea and PR China, 29 samples have been analyzed for the isotopic composition of the elements H, C and N. The results showed δ(2)H values between -94 and -79‰, for δ(13)C -27.9 to -23.7‰ and for δ(15)N 1.3-5.4‰ for Chinese ginseng. Korean ginseng gave δ(2)H ratios between -91 and -69‰, δ(13)C ratios between -31.2 and -22.4‰ and δ(15)N ratios between -2.4 and +7‰. Despite the overlap between the values for individual isotopes, a combination of the isotope systems gave a reasonable differentiation between the two geographic origins. Especially the statistically significant difference in δ(2)H ratios facilitated the differentiation between Korean and Chinese ginseng samples.

The application of isotope ratio mass spectrometry for discrimination and comparison of adhesive tapes.

Forensic scientists are frequently requested to differentiate between, or compare, adhesive tapes from a suspect or a crime scene. The most common polymers used to back packaging tape are polypropylene and polyvinyl chloride. Much of the oriented polypropylene (OPP) needed to produce packaging tapes, regardless of the tape brand, is supplied by just a few polymer manufacturers. Consequently, the composition of the backing material varies little. Therefore, the discriminating power of classical methods (physical fit, tape dimensions, colour, morphology, FTIR, PyGC/MS, etc.) is limited. Analysis of stable isotopes using isotope ratio mass spectrometry (IRMS) has been applied in the broad area of forensics and it has been reported that isotope analysis is a valuable tool for the identification of adhesive tapes. We have tested the usefulness of this method by distinguishing different South Korean adhesive tapes produced by just a few manufacturers in the small South Korean market. Korean adhesive tapes were collected and analysed for their isotope signatures. The glue of the tapes was separated from the backing material and these sub-samples were analysed for their H- and C-isotope composition. The result shows the possibility for discriminating most tape samples, even from the same brand. Variations within single rolls have also been investigated, where no variations in H- and C-isotope composition significantly exceeding the standard deviation were found.

Quantification of propane in biological materials by head-space GC.

Propane was measured in specimens taken from two persons who died from a LPG explosion in an apartment using head-space-GC/FID. Because of the variation of instrument performance and sample injection, the internal standard pentane was used. Calibration standards were prepared by injecting each calculated volume of pure propane gas into capped vials containing 2 ml of blood and 5 microl of internal standard. The calibration curve revealed good linearity from 0.09 microg/ml to at least 90 microg/ml. The method validation data also included repeatability and recovery. The propane quantities in blood, fat and brain tissue were between 0.27 and 71 microg/ml (microg/g) with the highest concentration observed in fat. The confirmation of propane was conducted by the means of solid phase micro-extraction and mass spectrometry.