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- P-ISSN2233-4203
- E-ISSN2093-8950
Vol.8 No.1
Abstract
Studies performed on heterogeneous reactions of hydroxyl radicals (OH) in aerosol materials of tropospheric interest are presented, focusing on the chemical ionization mass spectrometric approach. Kinetic investigations of these reactions reduced deviation in the estimation of OH concentration in the troposphere by atmospheric modeling from field measurements. Recently, OH uptake was investigated under wet conditions to acquire kinetic information under more realistic conditions representative of the troposphere. The information on the mechanism and kinetics of OH uptake by tropospheric aerosol materials will contribute to the updating of atmospheric models, allowing a better understanding of the troposphere.
Abstract
Analysis of quinidine for fish tissues using single drop microextraction (SDME) coupled with atmospheric pressure matrix assisted laser desorption/ionization mass spectrometry (AP-MALDI-MS) are reported. Optimization conditions; such as extraction solvent, extraction time, pH of the aqueous solution, salt additions (NaCl), stirring rate, matrix type and concentration are investigated. Linear dynamic range (μM), limit of detection, relative recovery%, and enrichment factor are 0.08-9.2, 0.05, 94.8±3.1- 98.5±3.3%, 4.34±0.28-4.40±0.30, respectively. SDME-AP-MALDI-MS shows good intraday and interday reproducibility.
Abstract
The effect of cationization agent concentration on glycan detection via matrix-assisted laser desorption/ionization time-offlight mass spectrometry (MALDI-TOF MS) was investigated using Na+ ions in the form of NaCl as the cationization agent. NaCl solution concentrations ranging from 1 mM to 1 M were investigated. Glycans from ovalbumin were mixed with the cationization agent solution and the 2,5-dihydroxybenzoic acid (2,5-DHB) matrix solution in a volume ratio of 1:1:1. The resulting mixture was loaded onto the MALDI plate. Two MALDI-TOF MS instruments (Voyager DE-STR MALDI-TOF MS and Tinkerbell RT MALDITOF MS) were used for detection of glycans. The best detection, in terms of the number of identified glycans, the peak intensity, and the signal-to-noise (S/N) ratio, was obtained with NaCl concentrations of 0.01–0.1 M for both MALDI-TOF MS instruments.
Abstract
Products containing any one or more of 26 fragrance allergens likely to cause contact allergies, are required under the 2008 domestic cosmetic law to be labeled when their concentrations exceed a certain range. This study focuses on the comparison and development of analytical methods based on headspace-solid phase micro extraction (HS-SPME) and liquid-liquid extraction (LLE) methods followed by GC-MS/MS for 24 of the fragrance allergens excepting for two natural materials in water samples. Using the developed HS-SPME method, 15 of the 24 fragrance allergens were analyzed and 9 compounds which have relatively low logKOW values (below about 2.5) were not extracted, and the correlation coefficient (r²) of the calibration curve for quantification showed linearity of 0.9969 or more, and the method detection limits (MDL) and the limits of quantification (LOQ) were 0.078 ~ 0.582 μg/L and 0.261 ~ 1.940 μg/L, respectively. In the case of using the optimized LLE method, all 24 fragrance allergens were analyzed, and the correlation coefficient (r²) of the calibration curve for quantification showed linearity of 0.9957 or more, MDL and LOQ were 0.020 ~ 0.138 μg/L and 0.065 ~ 0.440 μg/L, respectively.