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Volume 65, Issue 10
Displaying 1-7 of 7 articles from this issue
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Analytical Reports
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Kohei YAMAGUCHI, Chikako OKUMURA, Osamu MIKIArticle type: Analytical Reports
2016 Volume 65 Issue 10 Pages 559-562
Published: October 05, 2016
Released on J-STAGE: November 08, 2016
JOURNAL FREE ACCESSThe quantity of microalgae biomass has been evaluated mainly based on the cell density and dry weight. However, these direct measurement methods requires much time and effort. Therefore, indirect methods have been developed for rapid and easier measurements. Major examples are methods that take chlorophyll to account, such as an absorbance measuring method and a fluorescence intensity method. Since there was a report that the chlorophyll content changes at various microalgae growth stages, the accuracy of the measurement through various growth stages must be confirmed. Therefore, in this study, we examined the compatibility and accuracy of three indirect measurement methods: absorbance measuring method, fluorescence intensity method, and Coulter Counter method at each growth stage of microalgae. As a results, each indirect methods showed a high correction coefficient to both the cell density and the dry weight; no influence was observed regarding the growth stage and the measurement accuracy. However, each indirect method had their own characteristics. By considering the microalgae characteristic and the growth environment, a more accurate measurement can be made.View full abstractDownload PDF (666K)
Accounts
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Shin-Ichi OHIRAArticle type: Accounts
2016 Volume 65 Issue 10 Pages 563-573
Published: October 05, 2016
Released on J-STAGE: November 08, 2016
JOURNAL FREE ACCESSA fully automated in-line sample pretreatment system for ionic solute analysis that extracts the ionic analytes from the sample has been developed. Ionic analytes were selectively transferred from the sample to an acceptor solution by electric field. Large molecules, particulate, and nonionic compounds were not transferred at all, or a little. Furthermore, quantitative ion transfer was achieved within a few seconds. The transfer efficiencies were not affected by sample pH. The system was successfully applied to analyze inorganic cations and anions included oxoacids, organic acids, and cationic heavy metals in real samples, such as drinking water, urine, milk, wine, and animal serums. The present method could separately transfer the cations and anions into different acceptor solutions. This phenomenon was successfully applied to separate chromium species, Cr(III) and Cr(VI), which are cations and anions in the environment, respectively. Furthermore, quantitative ion transfer can be achieved for in-line enrichment. The sample solution was introduced into the ion transfer device with a relatively larger flow rate and ionic solutes was completely transferred into the acceptor solution flow with a relatively slower flow rate. In this case, ionic solutes were enriched in the acceptor solution. The enrichment factor depends on the flow rate ratio. The present electrodialytic method can simultaneously achieve matrices isolation, the separation of chromium spices and enrichment.View full abstractDownload PDF (1881K)
Technical Papers
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Syuji OKUYAMA, Minemasa HIDAArticle type: Technical Papers
2016 Volume 65 Issue 10 Pages 575-579
Published: October 05, 2016
Released on J-STAGE: November 08, 2016
JOURNAL FREE ACCESSA discrimination method between different kinds of fine paper has been studied using the mixing ratio of three kinds of rosins used as sizing agents. Tetramethylammonium hydroxide as an organic alkali, which converted the acid into its methyl derivatives, was added to pimaric acid, abietic acid and dehydroabietic acid in a glass vial, and the methyl esters of the rosin acids were prepared. Their methyl esters were measured by a gas chromatograph-mass spectrometer (GC-MS) and the proportions (%) of the three components were calculated by their peak areas on a total ion chromatogram (TIC). About nine kinds of fine paper, three parts of 5 mm × 10 mm in area for each paper were cut and the methyl esters of the acids were measured by GC-MS. Principal component analysis was carried out using the proportions of the three methyl esters and divided the nine kinds of paper into seven groups. This method will be useful in practical forensic examinations.View full abstractDownload PDF (612K) -
Kazutaka YAMAGUCHI, Shoji KURATAArticle type: Technical Papers
2016 Volume 65 Issue 10 Pages 581-586
Published: October 05, 2016
Released on J-STAGE: November 08, 2016
JOURNAL FREE ACCESSForensic discrimination of tomato products was investigated in this study. Twenty types of tomato products were analyzed by energy-dispersive X-ray spectrometry (EDX) and a liquid chromatograph/mass spectrometer (LC/MS) for developing their forensic discrimination. Elements of samples were analyzed by EDX and the colorants and saccharides were analyzed by LC/MS. Some samples were classified by morphological observations and starch-iodine reactions. Analytical results showed that samples of tomato juice were not perfectly classified because their ingredients were limited by Japanese Agricultural Standard, but twenty types of samples could be classified into sixteen groups. Accordingly, this study was very useful for the discrimination of tomato products.View full abstractDownload PDF (581K) -
Koji FURUKAWA, Toshiyuki KAWAGUCHI, Kiyonobu KUDO, Tomoko NAKAZAWA, Yu ...Article type: Technical Papers
2016 Volume 65 Issue 10 Pages 587-592
Published: October 05, 2016
Released on J-STAGE: November 08, 2016
JOURNAL FREE ACCESSAnalytical method for bromic acid in drinking water was examined by liquid chromatography/tandem mass spectrometry (LC/MS/MS). For the purpose of bromic acid which is the high polarity other ionic compounds are properly separated on chromatograms. We were investigated measurement conditions using a multi-mode column (reverse phase + anion-exchange) by introducing a quaternary ammonium group. Further, we have verified the linearity of the calibration curves, the selectivity, the accuracy (recovery) of this analytical method from the data of the recovery test in drinking water. Bromic acid may be properly separated from chloric acid, nitrate ion, bromide ion, chloride ion and sulfate ion using a multi-mode column. The peak shape of bromate ion was good by using a multi-mode column. Also, the calibration curve of bromate showed good linearity in the range of 0.1 – 10 μg L−1. The repeatability (0.1 μg L−1, n = 5) was below 6.11 %. In addition, the repeatability (4.13 %), and intermediate precision (5.16 %) and the accuracy (98.4 %) for bromate acid obtained by the recovery tests in drinking water (1 μg L−1, n = 5, 5 days) were satisfied based on the criteria in the guideline for the validation of testing method in drinking water, which has been notified by the Ministry of Health, Labour and Welfare, Japan.View full abstractDownload PDF (963K)
Notes
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Michiko EGAWA, Shogo SUGAHARA, Yasushi SEIKEArticle type: Notes
2016 Volume 65 Issue 10 Pages 593-598
Published: October 05, 2016
Released on J-STAGE: November 08, 2016
JOURNAL FREE ACCESSIn most sewage-treatment plants in Japan, chlorination has been performed before discharge into public water areas. The available chlorine remaining in the water after chlorination is called residual chlorine. We found that it was difficult to determine nitrite in water samples containing a high concentration of residual chlorine, such as sewage treatment water. Therefore, we aimed at the development of a method that is not affected by the residual chlorine, and have developed a simple technique for a spectrophotometric determination of nitrite nitrogen in a water sample containing a high concentration of residual chlorine. The technique removes residual chlorine by taking advantage of the oxidation-reduction reaction using a reducing agent. Hydroxylamine hydrochloride was optimum as the reducing agent. The standard procedure is as follows. A 20 mL sample solution containing residual chlorine was taken into a 25-mL test tube with graduation. A 0.1 mL of 8 mM hydroxylamine hydrochloride solution was added to the sample in the test tube. After standing for 5 minutes, nitrite was determined according to the conventional spectrophotometric method. For a water sample containing 35 μM of residual chlorine, nitrite was determinable by adding the range of 40-100 μM of hydroxylamine hydrochloride. From the addition and recovery test using sewage treatment water, we achieved a high recovery rate of 92-98 % with a RSD of 0.41-0.81 % to any chemical species of ammonium, nitrite and nitrate. The established method was successfully applicable to the water samples in a disinfection tank of a sewage treatment plant.View full abstractDownload PDF (632K)
Analytical Reports
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Yuko YUI, Shigenori OTA, Chiaki AOYAMA, Makoto TSUNODA, Atsushi SATOArticle type: Analytical Reports
2016 Volume 65 Issue 10 Pages 599-602
Published: October 05, 2016
Released on J-STAGE: November 08, 2016
JOURNAL FREE ACCESSIt is well known that phospholipids contained in physiological samples cause bad effects on determination using liquid chromatography-mass spectrometry (LC/MS). Sensitivity or reproducibility for compounds co-eluted with phospholipids are often diminished because of ion suppression. In this study, we investigated a sample pretreatment method for removal of phospholipids using 96-well plates packed with phosphate group-selective metal oxides. When serum samples were analyzed without the pretreatment, the sensitivity of warfarin, which was co-eluted with phospholipids, was decreased, and it was restored after the pretreatment with phosphate selective sorbent. Both the efficiency of removal of phospholipids and recovery of 11 drug compounds were sufficient when serum samples were analyzed by LC/MS after the pretreatment. In conclusion, removal of phospholipids using metal oxides is useful for analysis of biological samples with LC/MS.View full abstractDownload PDF (546K)
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