Combined liquid chromatograph mass spectrometer (LC-MS) for organic micro analysis was described. The review of the historical aspect on the development LC-MS interface is important to understand recent advanced methods for the analysis. Several problems found in the earlier developed interface are stated. The moving belt interface was the first successful desolvation method. The simplified method, such as direct liquid introduction (DLI) as well as thermospray (TSP), are discussed. Fast atom bombardment (FAB) ionization is available in the frit interface. The compositions of various spray methods are presented for the LC-MS interface including particle beam (PB), electrospray (ES), atmospheric pressure chemical ionization (APCI), sonic spray, droplet electrospray and ionspray. Several applications using these interfaces are shown. Recent mass spectrometers using Fourier transform (FT) technique which exhibits high mass resolving power and accuracy is one of the best analyzer for LC-MS work. Dual ion source equipped with matrix assisted laser desorption ionization (MALDI) and external ionization source are commonly available for FTMS. The new topics on the recent developed mass spectrometry are introduced.

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Principles and applications of inductively coupled plasma (ICP)-based multielement analytical methods, ICP atomic emission spectrometry and ICP mass spectrometry, were summarized briefly. Fundamentals and characteristics of these methods were explained in comparison with those of the atomic absorption spectrometry. The methods for the pretreatment and for the quality assurance of the data were also reviewed briefly. Finally, some of the biomedical and environmental applications of these methods were introduced.

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Chlorine dioxide (ClO₂) in a gas exhausted from a factory involved in the electrolytical soda process was measured. Three absorbing vessels connected in series were used for the simultaneous collection of ClO₂ and chlorine. Two vessels contained water to collect ClO₂ and coexisting chlorine, and the third one contained dimethylsulfoxide (DMSO) to capture ClO₂. DMSO was useful as an absorbing solution for ClO₂, because more ClO₂ was captured and remained in DMSO than in water. Moreover, DMSO eliminated interference from the coexisting chlorine. ClO₂ collected in water was determined by a voltammetric membrane electrode after the addition of DMSO. Chlorine was determined by colorimetry using o-tolidine. The concentrations of ClO₂ and chlorine in process gases ranged from 36 to 116 mg/m³ and from 16 to 51 g/m³, respectively.

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A single dose of methylmercury at 10 or 15 mg Hg/kg body weight (p.o.) does not have an apparent adverse effect on adult rats. However, when primary cerebellar cells were prepared from neonatal rats exposed to methylmercury in utero by administering methylmercury to pregnant rats on day 18 of gestation, cerebellar neurons died after a certain lag time with morphological changes characteristic to apoptosis : formation of apoptotic vesicles, disappearance of neurites and condensation of nuclear chromatin and internucleosomal cleavage of chromatin DNA. The apoptotic death of cerebellar neurons required diffusible factor (s) released from the methylmercury-loaded cells, which can also induce the death of cerebellar neurons from control animals. Cerebellar weight gain during the 10 d after birth was also retarded by the prenatal exposure to methylmercury. These results indicate that prenatal exposure to methylmercury at maternal doses which do not induce apparent abnormality in adult rats brings about an accumulation of methylmercury in cerebellar neurons sufficient to induce apoptotic death of those cells, which may be a cause of retardation of cerebellar development during early postnatal stage.

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An anion-exchange chromatography (IC) with pulsed amperometric detection of xylitol, D-sorbitol and D-mannitol in food was developed. These alcoholic sugars extracted with 80% ethanol from food were diluted 1000 times with water as IC samples. The detection limit of each standard sugar alcohol was 0.025 ppm (25 ppm in food). The sensitivity of this method was about 1000 and 30 times higher than those of high performance liquid chromatography (HPLC) with refractive index (RI) detection and gas chromatography (GC) with flame-ionization (FID) detection, respectively. Furthermore the sample treatment is simple compared with other methods. The recoveries of xylitol, D-sorbitol and D-mannitol added in foods were 77.8-104.0%.

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In our previous paper, we reported a phenomenon that adipate (AAE) utilized as the plasticizer for polyvinyl chloride cling films was hydrolyzed to alcohols and adipic acid when they were kept in contact with non-cooked foods. In this paper, the decomposition of adipates by fresh vegetables was investigated using di-2-ethylhexyl adipate (DEHA) and diisononyl adipate. AAE added to various fresh vegetables was decomposed after incubating at 35°C for 1 h to yield alcohols, which were undetected in the original vegetables. In the cases of fruit, cucumbers, tomatos and red peppers, it was found that the rate of the decomposion of AAE decreased as they were ripening. The AAE hydrolyzing component in cucumbers was extracted with 50 mM Tris-HCl buffer (pH 7.5) and only when 1% triton X-100 was added to the buffer the extraction was most efficient. The AAE decomposing activities of the extract showed the best result under the conditions of pH 7-7.5 and 35°C and were lost in the case of heating at 100°C for 5 min. This suggests that the decomposition of AAE is an enzymatic hydrolysis reaction. Other aliphatic dicarboxylic acid esters such as DEHA, di-2-ethylhexyl azelate, di-2-ethylhexyl sebacate and di-2-ethylhexyl dodecanediocate were also hydrolyzed by the cucumber extract, but as the carbon number of these acids increases, the rate of hydrolysis diminished. The molecular weight of the putative enzyme in the cucumber extract catalyzing the hydrolysis of AAE was estimated to be 25000-45000 by gel filtration chromatography on Sephadex G-100.

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A comparison of two extraction methods (Sep-Pak and blue rayon) of mutagens in the urine was demonstrated using the salmonella mutagenicity test. Most of the urine extracts with Sep-Pak tC₁₈ were more mutagenic than those with blue rayon. It was suggested that the Sep-Pak extraction method was useful for the evaluation of human exposure to carcinogens/mutagens in daily life based on the mutagenic activity of the urine.

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The optical isomers of amphetamine and methamphetamine in the human urine were clearly separated by direct HPLC analysis using a chiral stationary phase. This direct HPLC was applied to the enantiomeric resolution of amphetamines in the methamphetamine abusers' urine and in the Parkinsonian urine after (R)-(-)-deprenyl administration. (S)-(+)-Amphetamine and (S)-(+)-methamphetamine were only detected in the urine from several methamphetamine abusers. On the contrary, (R)-(-)-amphetamine and (R)-(-)-methamphetamine were only detected as metabolites in the Parkinsonian urine treated with (-)-deprenyl. Enantiomer analysis may provide valuable information about the original substrate in the metabolic pathway. This simple and convenient method is suitable for the enantiomeric analysis for forensic purposes.

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The purpose of this study was to use various atomic absorption spectroscopic techniques to investigate the amount of biological trace metals, including selenium, manganese, cobalt, chromium and zinc, in the urine of Blackfoot disease (BFD) patients. Urine specimens from BFD patients were collected, acidified with a mixed acid solution, purified and preconcentrated with a solid phase extraction cartridge before being digested in a microwave oven at controlled conditions prior to analysis. The optimum composition of the mixed acid was established according to the analysis of standard known sample. The level of urinary selenium and zinc was determined by hydride atomic absorption spectrophotometry (HAAS) and flame atomic absorption spectrophotometry (FAAS), respectively, whereas manganese, cobalt and chromium level were determined using graphite furnace atomic absorption spectrophotometry (GFAAS) with stabilized temperature platform furnace conditions. The validity of the analytical methods was confirmed by the analysis of standard known samples. The result showed that total urinary Mn, Co, Cr and Zn levels in BFD patients were significantly different than those in normal subjects (Mann-Whitney test, p<0.05). But the total urinary Se level in BFD patients did not differ from those in normal control subjects (p>0.05). The possible connection of these elements with the etiology of the disease is discussed.

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