• Analytical Science and Technology
• /
• v.30 no.3
• /
• pp.122-129
• /
• 2017

Methamphetamine addiction is a critical issue due to the lack of effective pharmacotherapy and high potential for relapse. Nevertheless, there are no distinct biomarkers for diagnosis or prognosis for methamphetamine addiction. In the present study, a rat model for methamphetamine self-administration was established and alteration of urinary metabolites by methamphetamine addiction was investigated by the targeted metabolite analysis using mass spectrometry. Rat urine samples were collected at three time points (before and after addiction and after extinction) from the methamphetamine-addicted group as well as the age-matched control group. The collected samples were prepared using AbsoluteIDQ p180 kit and analyzed using flow injection analysis (FIA) - or high performance liquid chromatography (HPLC) - tandem mass spectrometry (MS/MS). The levels of lysine, acetylornithine and methioninesulfoxide were distinctively altered depending on the status of metheamphetamine addiction or extinction. In particular, the level of acetylornithine was reversely changed from addiction to extinction, for which further studies could be useful for biomarker discovery or mechanistic studies for methamphetamine addiction.

• Korean Journal of Clinical Pharmacy
• /
• v.15 no.1
• /
• pp.61-67
• /
• 2005

This study was designed to establish a strategy for the bioequivalence study of doxifluridine, an anticancer drug, in dogs instead of cancer patients. Although the results from animals may not occur in the same manner from human, those would be worth enough in terns of the bioequivalence. As for critically ill population such as cancer patients, bioequivalence studies in animals bring many advantages. Six healthy Beagle dogs were selected on the basis of hematology and blood chemistry test. After an over night fast, 200 mg of doxifluridine was orally administered, and blood was serially taken up to 12 hours. Plasma concentration of doxifluridine was measured using a newly validated bioanalytical method by a HPLC coupled tandem mass spectrometry. Time course of plasma doxifluridine concentration was analyzed with non-compartmental and compartmental approaches. Consequently, we represented hematology and blood chemistry database for the selection of healthy Beagle dogs, and suggested a sensitive and validated analytical method of doxifluridine, as well as a study design for the bioequivalence of doxifluridine in dogs.

• Mass Spectrometry Letters
• /
• v.3 no.2
• /
• pp.39-42
• /
• 2012

Phosphorylation and glycosylation are two of the most important and widespread post-translational modifications (PTMs) in an organism. Proteomics analysis of the PTMs has been challenged by low stoichiometry of the modified proteins and suppression effects by high abundance proteins, typically no-functional house-keeping proteins. In this study, a novel method was applied for not only isolating PTM peptides from intact peptides but also concurrently characterizing of glyco- and phosphoproteome using electrostatic repulsion hydrophilic interaction chromatography (ERLIC) packed with silica coated by crosslinked polyethyleneimine. For 2 mg tryptic digest of mouse proteome of epicardial adipose tissue with fat diet, 802 N-glycosylated peptides of 316 glycoproteins and 159 phosphorylated peptides of 75 phosphoproteins were identified using HPLC chip/quadrupole time-of-flight (Q-OF) tandem mass spectrometer.

• The Korean Journal of Food And Nutrition
• /
• v.28 no.1
• /
• pp.143-152
• /
• 2015

Vitamin D contents in agricultural products and foods were quantified by high performance liquid chromomatography (HPLC) with a UV/Vis detector, using external standard methods. The results were confirmed with liquid chromatography tandem mass spectrometry (LC-MS/MS). After homogenization, samples were hydrolyzed by direct alkali saponification. Thereafter, fat-soluble components were extracted with n-hexane containing 0.01% butylated hydroxytoluene (BHT). Vitamin D contents in cereals were found to be in the range of $1.882{\sim}4.856{\mu}g/100g$. Juda's ear and oak mushroom contained high amounts of vitamin D, at 363.85 and $199.42{\mu}g/100g$ of edible portion, respectively.

• Korean Journal of Clinical Pharmacy
• /
• v.16 no.1
• /
• pp.52-56
• /
• 2006

Aceclofenac, a nonsteroidal antiinflammatory agent of a phenylacetic acid type, has been used for rheumatoid arthritis and osteoarthrits. Although the metabolic pathway of aceclofenc is relatively well-known in vitro, pharmacokinetic profiles of its three major or metabolites are still unclear in human. The present study was designed to investigate pharmacokinetic profiles of the metabolites of aceclofenac, and to evaluate the bioequivalence of the generic preparation of aceclofenac 100 mg tablet. Blood samples were serially collected for a period of 12 hours following a single oral administration of 100 mg aceclofenac in 20 healthy human volunteers. A simple protein precipitation with acetonitrile was employed to purify those substances from plasma. Aceclofenac, diclofenac, 4'-hydroxyaceclofenac and 4'-hydroxy-diclofenac in heparinized plasma were simultaneously measured with flufenamic acid, an internal standard, using HPLC coupled to a tandem mass spectrometer. Time courses of 4'-hydroxydiclofenac, diclofenac and aceclofenac plasma concentrations were clearly revealed, and the pharmacokinetic properties were analyzed. The 90% confidence intervals for the ratios of test/reference for log-transformed AUC and $C_{max}$ lie within 0.80-1.25.

• Journal of Korean Society for Atmospheric Environment
• /
• v.34 no.1
• /
• pp.120-143
• /
• 2018

The analytical methods and their ambient levels of organic nitrogenous compounds such as nitrosamines, nitramines (nitroamines), imines, amides and nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) in the atmosphere are summarized and discussed. Sampling for the analysis of organic nitrogenous compounds was mostly conducted using high volume air sampler. The direct liquid extraction (DLE) using sonification and the pressurized liquid extraction (PLE) using the accelerated solvent extraction (ASE) have been frequently employed for the extraction of organic nitrogenous compounds in the atmospheric samples. After extraction, clean-up via filtration and the solid phase extraction (SPE) and concentrations using nitrogen and rotary evaporator have been generally conducted but in some studies the clean-up and concentration steps have been omitted to prevent the loss of analyte and improve the recovery rate of the analytical procedure. Instrumental analysis was mainly carried out using gas chromatography (GC) or the high performance liquid chromatography (HPLC) coupled with the single quadrupole mass spectrometer or tandem mass spectrometer in the electron ionization (EI), positive chemical ionization (PCI) and negative chemical ionization (NCI) mode and analysis sensitivity of nitrosamines and nitramines were higher in NCI mode. Desirable sampling and analysis methods for analyzing particulate organic nitrogenous compounds are suggested.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.61 no.1
• /
• pp.57-63
• /
• 2016

Soyasaponin I, II, III and V contents were investigated in seed, cotyledons and sprouts of soybean (Glycine max (L.) Merill) subjected to germination over five days. High-performance liquid chromatography coupled with tandem mass spectrometric (HPLC-MS/MS) method was used to evaluate the content of soyasaponins. Soyasaponins contents were different according to the varieties. Germination of soybeans dramatically increased soyasaponin contents in soybean sprouts in a time-dependent manner. Cotyledons had a higher contents of soyasaponins compared to dried seed (p<0.05). After five days of germination, Soyasaponin I and II increased 10 times higher after germination. Soyasaponin I and II are major metabolites in cotyledons and hypocotyls. Soyasaponin III and V were also detected in seed and increased depended on the germination stage. Soyasaponin V was at its highest levels in the hypocotyl, almost 7 times higher than the initial content in soybean seeds. Therefore, the germination of soybean sprouts significantly increased soyasaponin content.

• Korean Journal of Food Science and Technology
• /
• v.43 no.5
• /
• pp.544-552
• /
• 2011

The purpose of this study was to develop an analytical method for determining 15 polycyclic aromatic hydrocarbons (PAHs) of EU priority using gas chromatography (GC)-tandem mass spectrometry (MS). The PAHs in ground coffee were analyzed after being extracted using methods such as saponification-liquid-liquid extraction, Soxhlet extraction, and solid-liquid extraction. The solid-liquid extraction method showed the greatest repeatability and most efficient reduction of the matrix effect. GC-tandem MS for the quantification of the 15 PAHs showed better resolution and lower limit of detections (LODs) than GC-MS-selected ion monitoring (SIM) and high performance liquid chromatography with fluorescence detector. LODs of this method for the ground coffee types were 0.002-0.1 ${\mu}g/kg$ and limit of quantifications (LOQs) were 0.006-0.2 ${\mu}g/kg$ The recoveries ranged from 52.6 to 93.3%. Forty-six commercial types of ground coffee were analyzed to determine their PAHs contamination levels. PAHs concentration ranged from ND to 5.988 ${\mu}g/kg$. This study was conducted with toxicity equivalence factors, the U.S. EPA recommendation to identify dietary risks for PAHs in different types of coffee. The estimated average daily dose of PAHs was $5.24{\times}10^{-8}$ mg/kg body weight/day.

• Journal of fish pathology
• /
• v.34 no.1
• /
• pp.71-80
• /
• 2021

Cephalexin, a semi-synthetic cephalosporin antibiotic, has long been used in fish aquaculture in various countries under legal authorization. The drug is thus widely available for use in other aquatic species except fishes like the crustacean whiteleg shrimp. This study aims to develop a sensitive method for laboratory residue studies to adopt in withdrawal period determinations. Through repeated trials from the existing methods developed for other food animal tissues, it was possible to achieve a sensitive high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method. The results showed that at a concentration of 0.1 mg/kg, the recovery rate was 81.79%, and C.V. value was 8.2%, which meet the recovery rate and C.V. recommended by Codex guideline. After satisfactory validation of analytical procedures, applicability to the shrimp tissue was confirmed in experimentally cephalexin-treated whiteleg shrimp. As a result, most muscle samples were detected below the limit of quantification (0.05 mg/kg) after day 3, and most hepatopancreas samples were detected below the limit of quantification after day 14. In particular, the limit of quantification 0.05 ppm with the presently developed method suggests sufficient sensitive over the current legal maximum residue limit of 0.2 mg/kg set for fishes.

• Journal of Food Hygiene and Safety
• /
• v.21 no.2
• /
• pp.47-51
• /
• 2006

The formed acrylamide in many fried and baked starchy foods is in consequence of its formation during frying and preparation methods. Being acrylamide established to be a toxic substance, the implications to public health from amounts found in food are not clear. So this study was carried out to investigate the contents of acrylamide of French fries and snacks in addition to acrylamide formation in relation to water and lipid in foods. The raw materials of foods used in the experiments were wheat, potato, com and rice. The preparation of foods was modified in a little to raise the recovery ratio and contents of water and lipid were analyzed to the public food method. The contents of acrylamide were measured by the liquid chromatography tandem mass spectrometry. The average level of acrylamide produced in snacks is $236{\pm}322$ ppb and potato snacks came out the highest value at $521{\pm}403$ ppb in 104 snacks. The formation of acrylamide in fried food was found to depends on the composition of raw material not on water and lipid contents in food and not on storage period and temperature.