Study on the spectroscopic reconstruction of explosive-contaminated overlapping fingerprints using the laser-induced plasma emissions

Yang, Jun-Ho,Yoh, Jai-Ick The Korean Society of Analytical Science 2020 분석과학 Vol.33 No.2

Reconstruction and separation of explosive-contaminated overlapping fingerprints constitutes an analytical challenge of high significance in forensic sciences. Laser-induced breakdown spectroscopy (LIBS) allows real-time chemical mapping by detecting the light emissions from laser-induced plasma and can offer powerful means of fingerprint classification based on the chemical components of the sample. During recent years LIBS has been studied one of the spectroscopic techniques with larger capability for forensic sciences. However, despite of the great sensitivity, LIBS suffers from a limited detection due to difficulties in reconstruction of overlapping fingerprints. Here, the authors propose a simple, yet effective, method of using chemical mapping to separate and reconstruct the explosive-contaminated, overlapping fingerprints. A Q-switched Nd:YAG laser system (1064 nm), which allows the laser beam diameter and the area of the ablated crater to be controlled, was used to analyze the chemical compositions of eight samples of explosive-contaminated fingerprints (featuring two sample explosive and four individuals) via the LIBS. Then, the chemical validations were further performed by applying the Raman spectroscopy. The results were subjected to principal component and partial least-squares multivariate analyses, and showed the classification of contaminated fingerprints at higher than 91% accuracy. Robustness and sensitivity tests indicate that the novel method used here is effective for separating and reconstructing the overlapping fingerprints with explosive trace.

Simultaneous determination of illegal galactagogue adulterants in supplement diets by LC-MS/MS

Lee, Ji Hyun,Cho, So-Hyun,Park, Han Na,Park, Hyoung Joon,Kim, Nam Sook,Park, Sung Kwan,Kang, Hoil The Korean Society of Analytical Science 2018 분석과학 Vol.31 No.4

Recently, for successful lactation, many breastfeeding mothers seek various products, including herbal medicine, dietary supplements, and prescribed medicines, to improve milk production. As demand for galactogogues grows, it is highly possible that pharmaceutical galactogogues may be adulterated with illegal products to maximize their efficacy. For continuous control and supervision of illegal products, we developed and validated a simple and sensitive LC-MS/MS method capable of simultaneously determining five galactogogues. Chromatographic separation was conducted using an Agilent Poroshell $120SB-C_{18}$ column with a mobile phase consisting of 20 mM ammonium formate (pH 5.4) and 100 % acetonitrile. The total run time was 13 min per analyte. The proposed method was performed according to the guidelines of the International Conference of Harmonization and it produced reliable results. This method showed high sensitivity and specificity, with a limit of detection (LOD) and limit of quantitation (LOQ) of 0.01-0.82 ng/mL and 0.02-2.45 ng/mL, respectively, for the solid- and liquid-type samples. Specificity was evaluated by analyzing matrix-blank samples spiked with the target compounds at LOQ levels, which provided a good separation of all peaks without interference. Additionally, the repeatability and intermediate precision were typically <15 %, whereas the recovery was 80-120 % of the values obtained using blank samples. Thus, we concluded that this method could be used for the identification and quantification of galactogogues in food or herbal products.

The Significance of the Analytical Sciences In Environmental Assessment

Chung, Yong,Ahn, Hye-Won The Korean Society of Analytical Science 1995 분석과학 Vol.8 No.4

The quality of human life is directly related to the quality of the environment. To assess environmental quality we must first determine the MCLG(Maximum Contaminant Level Goal), MCL(Maximum Contaminant Level), environmental impact and so on. The MCLG is the concentration at which no known adverse health effects occur. The MCLG is determined by risk assessment identifying which process is hazardous assessing, dose-response, human exposure, and characteristics of risk. With consideration of analytical methods, treatment technology, cost and regulatory impact, the MCL is set as close to the MCLG as possible. In this way, determination of the concentration and national distribution of contaminants is important for assessment of environmental quality The analytical sciences pose potential problems in assessing environmental quality. Continuing improvement in the performance of analytical instruments and operating technique has been lowering the limits of detectability. Contaminant concentration below the detection limit has usually been reported as ND(Not-Detected) and this has often been misunderstood as equivalent to zero. Because of this, more the contaminant concentration in the past was below the detection limit, whereas contaminants can be quantified now even though the contaminant concentration might remain the same or may even have decreased. In addition, environmental sampling has various components due to heterogeneous matrices. These samples are used to overestimate the concentration of the contaminant due to large variability, resulting in excess readings for MCL. In this paper, the significance of the analytical sciences is emphasized in both a conceptual and a technical approach to environmental assessment.

Analytical Application of Glow Discharge Atomic Absorption Spectroscopy (GD-AAS) Using Three Types of Jet Configurations Under Power Mode

Hwang, Jun Ho,Lee, Ki Beom,Kim, Min Su,Lee, Seong Ro,Kim, Hasuck,Kim, Hyo Jin,Lee, Gae Ho The Korean Society of Analytical Science 1995 분석과학 Vol.8 No.4

Three anode configurations of six-jet, cone-jet and cylindrical-jet are tested for their analytical performance under power mode operation. The effect of pressure, power and gas flow rate on atomic absorption signals have been studied. The increase of atomic absorption signal of sample element is observed at a fixed pressure in all configurations as the gas flow rate increase up to 300-600 seem, and as the power dissipated in the glow discharge cell increase. The lower the pressure is in the glow discharge cell at a fixed discharge power and argon flow rate, the greater the absorbance of sample element is. The optimum conditions are taken from these data and a calibration curve of Cu in low-alloy steel sample is obtained. In this calibration curve, six-jet configuration shows the best analytical results varies as the sample element.

Analytical characterization of O₃ samples prepared for investigation of tropospheric heterogeneous reactions

Kim, Mihyeon,Park, Jong-Ho The Korean Society of Analytical Sciences 2022 분석과학 Vol.35 No.5

In this study, ozone (O₃) samples were prepared for investigating the heterogeneous reactions between O₃ and tropospheric aerosols and were characterized by spectroscopic methods. O₃ generated from an ozone generator was purified by selective adsorption on refrigerated silica gel, followed by transfer to a sample bulb. The amount of UV light (λ = 256 nm) absorbed by O₃ was measured as a function of time at two different temperatures (room temperature and 50 ℃) and under different irradiation conditions. A correlation plot of 1/[O₃] versus time showed that O₃ decomposition follows the 2^nd order reaction rate under a steady-state approximation. The initial concentration of O₃, observed rate constants (k_obs), and the half-life of O₃ in the sample stored at room temperature were determined to be 2.74 [±0.14] × 10¹⁶ molecules·cm^-3, 4.47 [±0.64] × 10^-23 molecules^-1·cm³·s^-1, and 9.5 [±1.4] days, respectively. The evaluation of O₃ stability under various conditions indicated that special care should be taken to prevent the exposure of the O₃ samples to hightemperature environment and/or UV radiation. This study established a protocol for the preparation of highly purified O₃ samples and confirmed that the O₃ samples can be stored for a day after preparation for further experiments.

Applications of Scanning Electrochemical Microscopy

Bard, Allen J.,Fan, Fu-Ren F. The Korean Society of Analytical Sciences 1995 분석과학 Vol.8 No.4

The application of scanning electrochemical microscopy to the imaging of surfaces in water and air and to the study of the electrochemistry of single molecules is discussed.

Industry's Response to the Green Movement

Little, Barry F.P. The Korean Society of Analytical Science 1995 분석과학 Vol.8 No.4

This paper describes how industry has responded to the environmental challenge. Benefits include compliance with environmental legislation; genuine reductions to environmental impact; sustainable improvements to profitability in the face of increased competitive pressure. National and international Standards for environmental management offer security and direction for a company wishing to improve environmental performance and coupled with a waste minimisation strategy many financial and environmental benefits can be achieved. Introduction of new technical skills, techniques and worker understanding to aid motivation is an essential component of such a strategy. Monitoring and targeting has a key role to play in the establishment of improved environmental performance.

Some Peroxysterols and Ceramides from "Phellinus ribis", a Korean Wild Mushroom

Moon, Dongcheul,Hwang, Kyunghwa,Choi, Kyuyeol,Choi, Dongcheol,Kim, Changsoo,Kim, Jaegil,Lee, Yongmoon,Zee, Okpyo The Korean Society of Analytical Science 1995 분석과학 Vol.8 No.4

Studies on the chemical constituents from a Korean wild mushroom, Phellinus ribis, were carried out. A triterpenoid, two peroxysterols, and a chlorobenzene compound were isolated from the hexane soluble fraction of the methanol extract of dried fruiting bodies of the basidomycetes. Those compounds identifed were 3-hydroxy-20(29)-lupen-28-oic acid (betulinic acid), 5,8-epidioxyergosta-6,22-dien-3-ol(ergosterol peroxide), 5,8-epidioxyergosta-6,9(11),22-trien-3-ol (dehydroperoxyergosterol), and 1,2,4,5-tetrachloro-3,6-dimethoxybenzene. Structural studies were carried out on molecular species of a ceramide and cerebroside isolated from the chloroform soluble fraction of the methanol extract. For ceramide, the major component fatty acids were a-hydroxy fatty acid isomers of $C_{22:00}{\sim}C_{25:00};$ the predominant long-chain bases were trihydroxy sphinganine of $C_{17}{\sim}C_{18}$. The structure of a cerebroside containing mono-sugar was assumed that the long-chain base was $C_{19:2}$ sphingadienine; the major fatty acids were $C_{16}{\sim}C_{15}$ ${\alpha}$-hydroxy fatty acid isomers.

DNA Ligand - Redox Active Molecule Conjugates as an Electrochemical DNA Probe

Ihara, Toshihiro,Maruo, Voshiyuki,Uto, Yoshihiro,Takenaka, Shigeori,Takagi, Makoto The Korean Society of Analytical Science 1995 분석과학 Vol.8 No.4

Toward the development of universal, sensitive, and convenient method of DNA (or RNA) detection, two kinds of electrochemically active DNA ligands. acridine - viologen and oligonucleotide - ferrocene conjugate, were prepared. Thermodynamic and electrochemical study revealed that these probes bound strongly to DNA, and showed a typical cyclic voltammograms, indicating a potential for use as a reversible electrochemical labelling agent for DNA. Especially, using the electrochemically active oligonucleotide, we have been able to demonstrate the detection of DNA at femtomole levels by HPLC equipped with ordinary electrochemical detector (ECD). These results lead to the conclusion that the redox-active probes are very useful for the microanalysis of nucleic acid due to the stabilily of the complexes, high detection sensitivity, and wide applicability to the target structures (single- and double strands) and sequences.

Molecular Analysis using High Performance Capillary Electrophoresis

Yoo, Young Sook,Ban, Eun Mi,Kim, Young Sook,Han, Yeosun,Park, Jongsei The Korean Society of Analytical Science 1995 분석과학 Vol.8 No.4

Several forms of gangliosides have been separated from various types of biological matrices using cyclodextrin-modified capillary zone electrophoresis (CZE). Quantitative analysis of phospholipids from biological fluids was achieved by micellar electrokinetic capillary chromatography (MECC) using 35mM sodium dodecyl sulfate. Phosphorylation, one of the most important post-translational modifications of proteins at serine, threonine and tyrosine residues in small peptides were identified and quantitative analyses of phosphopeptides were performed. Seven different neuropeptides which are relative the pain reachanism in the vertebrate central nervons system were also separated by CZE.