Vol. 47, No. 1
January 1998
Jun KOSHOUBU*, Yusei OHKUBO** and Tetsuo IWATA*
*JASCO Technical Research Laboratories Corporation, 2097-2, Ishikawa-cho, Hachioji-shi, Tokyo 192
**JASCO Corporation, 2967-5, Ishikawa-cho, Hachioji-shi, Tokyo 192
We carried out simultaneous determination of the base number and acid number in polyester polymer for paints using the PLS1 method in near-infrared transmission spectroscopy. In order to correct the background absorption due to scattering from the surface of the sample cell, and the sample itself, we derived absorption-coefficient spectra from a theoretical diffuse-transmission equation. The results of PLS1 analysis showed a good correlation with those obtained from the conventional titration method.
Keywords: near-IR spectroscopy; PLS1 method; base number; acid number; polyester polymer.
Shin-ichiro OKAWA and Tosimi ISHIKAWA*
*Department of Chemistry, College of Humanities and Sciences, Nihon University, 3-25-40, Sakurajosui, Setagaya-ku, Tokyo 156
(Received 25 July 1997, Accepted 2 October 1997)An ion-exchange chromatographic method using postcolumn derivatization with 10-(2-pyridylazo)-9-phenanthrol (PAP) in a nonionic surfactant solution of Brij35 was established for the separation and determination of copper(II) and zinc(II). The optimum conditions for the determining the elements were: an eluent containing 0.25 mol dm-3 lactic acid (pH 3.30) at a flow rate of 1 ml min-1; for postcolumn derivatization, a 2×10-4 mol dm-3 PAP solution containing 4% (v/v) dioxane, 4% (w/v)Brij35 and sodium tetraborate at a flow rate of 0.3 ml min-1; pH at the drain, 10.0±0.1; analytical column, a Shim-pack IC-C1 (5.0 mm i.d×150 mm); oven temperature of 40°C; an injection volume of 20 l; and detection at 545 nm. A liner relationship was observed between the peak hight and the amount of elements within the range of 100~800 ppb for manganese, 50~300 ppb (Cu) and 10~150 ppb (Zn), respectively. The relative standard deviation was 1.7, 2.1, 1.2% (n=6) for those elements having a concentration of 100 or 200 ppb; the detection limits of the elements were 17, 11, and 3 ppb (S/N=3), respectively. The present method was applied to the separation and determination of copper(II) and zinc(II) in the Rice flour (NIST SRM 1568a) with satisfactory results.
Keywords: postcolumn ion-exchange chromatography; 10-(2-pyridylazo)-9-phenanthrol; separation and determination of copper(II) and zinc(II); Rice Flour (NIST SRM 1568a).
Seiichi YOSHIDA*, Masahiro TAJIMA** and Tasuku TAKAMATSU*
*Safety & Analytical Research Center, Shiseido Research Center, 1050, Nippa-cho, Kohoku-ku, Yokohama-shi, Kanagawa 223
**Pharmaco Science Research Laboratories, Shiseido Research Center, 1050, Nippa-cho, Kohoku-ku, Yokohama-shi, Kanagawa 223
The versatility of a multiple mass spectrometric strategy for the structural characterization of proteins and peptides using complementary fast atom bombardment (FAB) and matrix-assisted laser desorption ionization (MALDI) in combination with liquid chromatography/electrospray ionization mass spectrometry (LC/ESI MS) has been investigated. Recombinant "Maxadilan" (r-Max), a potent vasodilator peptide from Lutzomya longipalpis, was used as a sample. An accurate mass measurement of intact r-Max by LC/ESI MS provided a direct confirmation of the presence of two intramolecular disulphide linkages. The hydrophilic and low-molecular-weight fragment of the chymotryptic digest of reduced and carboxymethylated r-Max could be detected, although it was difficult to detect by either FAB or MALDI alone; also a complete mapping of the primary structure of r-Max was achieved. An LC/ESI MS measurement of the tryptic digest of r-Max revealed fragments containing Cys5-Cys9 and Cys18-Cys55 linkages, and allowed the locations of the two disulphide linkages to be determined in a single analysis. The results fully support the value and position of LC/ESI MS in a multiple mass spectrometric strategy.
Keywords: Maxadilan; LC/ESI MS; primary structure; disulphide linkage; multiple mass spectrometric strategy.
Tosio SHIGEMATSU*
*NTT Opto-electronics Laboratories, Nippon Telegraph and Telephone Corporation, Tokai, Ibaraki, 319-11
(Received 11 September 1997, Accepted 29 October 1997)There are two techniques for labelling elements one is to irradiate the element with reactor neutrons; the other involves spiking it with its carrier-free radioisotope. With the former technique, the specific activity of an element of an element is the same for samples irradiated with reactor neutrons under the same conditions. In contrast, it is inversely proportional to its content with the latter. The author proposes a substoichiometric separation analysis, in which an element is labelled with two of its radioisotopes by these two techniques. With this method the specific activity of the elements is substituted by the ratio of the radioisotope activities, and the content can be determined by comparing the specific activities of test and standard samples without the need to consider error factors during chemical separation. These analytical methods were also applied to the determination of yttrium in high-Tc superconducting oxides and in rubidium carbonate. It was confirmed that they were more accurate than conventional substoichiometric analyses.
Keyword: substichiometric separation analysis; two labelling techniues; yttrium in superconducting oxides; rubidium carbonate.
Hitoshi ANDO*, Yasuaki INOUE* and Sizuo SATOH*
*Kawasaki Municipal Research Institute for Environmental Protection, 20-2, Tajima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa 210
(Received 20 December 1996, Accepted 30 October 1997)The analytical accuracy of suspended particulate matter (SPM) on a filter was investigated by a wavelength dispersive-type X-ray fluorescence spectrometer in both an empirical correction procedure method (EC) and a fundamental parameter method (FP). SPM samples were collected on a membrane filter with a low-volume air sampler. In this work, we analyzed 15 elements of 103 samples and investigated the accuracy of these quantitative methods in comparison with the measured values by AAS and IC. In the case of EC, a very good agreement could be confirmed for 10 elements (Ca, Ti, V, Cr, Mn, Fe, Cu, Ni, Zn, Pb). The correlation coefficient was 0.89 to 1.00. Also the matrix-effect correction was made better a correlation for 4 elements (Na, Mg, Cl, K), Though Al was better without any matrix-effect correction. In case of FP, the samples were treated as thin-layer samples, they were equal to EC in analytical accuracy, judging from the repeatability. On the other hand, samples were treated as bulk samples, the accuracy concerning which was aggravated. The average of the correlation coefficient made worse by 0.17 points. In addition, the management accuracy of the equipment, a sample for standardization of the instrument was prepared with poly-vinylalcohol and active carbone as a carrier. The coefficients of the variation of the X-ray intensities of the elements were less than 7.5% for measurements under 12 different dates during 12 months. This sample could be used for the standardization of the instrument for a long time, judging from the repeatability.
Keywords: X-ray fluorescence analysis; multi-elemental analysis; suspended particulate matter; empirical correction procedure method; fundamental parameter method.
Kazuhiro TSUTSUMI* and Kazuya OHGA**
*Criminal Investigation Laboratory, Oita Prefecture Police Headquarters, 3, Otemachi, Oita 870
**Department of Applied Chemisty, Faculty of Engineering, Oita University, Dannoharu, Oita 870-11
The effectivenesses and limitations of high-performance liquid chromatography (HPLC) and capillary electrophoresis (CE) are described for the discrimination of red and blue pen inks. Reversed-phase HPLC using acetonitrile/3% aqueous KBr (7: 1, v/v) as the eluent makes it possible to differentiate seventeen out of nineteen oil-based ball-point pen inks by a combined comparison of the chromatographic patterns, peak-height ratios and absorption spectra on 3D chromatograms for the dyestuff constituents. An analogous chromatographic comparison distinguishes twenty-seven oil-based marking pen inks, except for five, if the isocratic elution is combined with a gradient one. CE is more useful than reversed-phase HPLC in discriminating among aqueous pen inks which contain ionic dyestuffs. Electrophoresis with 15 mM borate buffer of pH 8.8 gives significant differences in the electropherogram to twenty two out of twenty six red roller-ball and marking pen inks. The CE of aqueous blue pen inks containing basic dyestuffs requires the addition of β-cyclodextrin and ethanol to the carrier electrolyte, permitting us to distinguish twenty-two inks other than one pair of inks.
Keywords: forensic ink analysis; red and blue pens; dyestuffs; HPLC; capillary electrophoresis.
Kazuhiko KURUSU, Kouichi TUYUKI*, Satoshi SUZUKI, Ryou SHOUZI** and Toshimi YAMAMOTO*
*Yokohama R & D Laboratories, The Furukawa Electric Co., Ltd., 2-4-3, Okano, Nishi-ku, Yokohama-shi, Kanagawa 220
(Received 16 July 1997, Accepted 9 September 1997)After aluminium alloys were dissolved with boiling phenol, intermetallic compounds having an insoluble character were separated from the matrix by filtration. The contents of the intermetallic compounds and the solid solutions were determined by inductively coupled plasma atomic-emission spectrometry. Al-Mg and Al-Mg-Si alloys were assayed. The total values of the intermetallic compounds and the solid solutions in each sample were almost equal to the contents value of a bulk. We have compared most of iron in Al-Mg sample alloys with the tensile strength, yield stress and elongation. On the whole, a decrease in amounts of iron in intermetallic compounds tends to decrease both strength and yield stress.
Keywords: aluminium; aluminium alloy; intermetallic compounds; solid solution; ICP-AES; phenol.
Toshiyuki MITSUI, Minemasa HIDA and Shuji OKUYAMA*
*Criminal Science Laboratory, Aichi Police H.Q., 2-1-1, Sannomaru, Naka-ku, Nagoya-shi, Aichi 460
(Received 12 June 1997, Accepted 6 October 1997)Coumarin is added to kerosene and A fuel oil for the descrimination of light oil. When kerosene and A fuel oil are used as light oil for the purpose of tax evaluation, the coumarin content in the oil is checked based on by fluorescence. However the official method for determining coumarin could not obtain a high degree of accuracy. A multivariate analysis was used to improve the official method. The analytical method is as follows. Five ml of 1.5 N sodium hydroxide is added to 10 ml of sample oil. The coumarin is changed to the cis-o-hydroxy cinnamic acid. After shaking, a sodium hydroxide layer is diluted 50 times with water. One ml of this solution is put into a quartz cell. The cis-o-hydroxy cinnamic acid in sodium hydroxide solution is changed to the isomer (trans-o-hydroxy cinnamic acid) by ultraviolet rays. The coumarin in kerosene and A fuel oil was determined by multivariate analysis (principal component analysis, principal component regression, partial least squares). By this method, the coumarin in kerosene and A fuel oil could be determined to a high degree of accuracy.
Keywords: coumarin in kerosene and A fuel oil; fluorescence; multivariate analysis such as principal component analysis, principal component regression and partial least squares regression.
Manabu OKAZAKI, Hideji TANAKA*, Tohru ETO, Michio MATSUBARA** and Kensaku OKAMOTO*
*Faculty of Pharmaceutical Sciences, The University of Tokushima, 1-78-1, Shomachi, Tokushima 770
**Seiko Instruments Inc., 1-8, Nakase, Mihama-ku, Chiba 261
A method for the determination of gallium at the µg dm-3 level by ICP-MS was studied as a basis for serum analysis. Coexisting NaCl (>0.01%) markedly reduces the ion intensities of 69Ga and 71Ga, whereas glucose (0.01~0.1%) does not interfere with the determination. Cobalt was found to be effective as an internal standard element, so as to correct for any matrix interference from NaCl. The method was applied to analyses of 1000- to 10- fold diluted serum samples spiked with Ga. The polyatomic ion (37Cl16O2) interference with the 69Ga intensity became significant when 10-fold diluted serum was analyzed. Therefore, a measurement of the ion intensity at 71Ga was preferred in order to obtain reliable results.
Keywords: ICP-MS; determination of gallium; serum analysis; cobalt internal standard method.
Ikuo WATANABE*, Ichirou TAKEZAWA** and Hirosi TAGO***
*National Institute of Public Health, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108
**Tohrin Co., 5-6-24, Yotsugi, Katsusika-ku, Tokyo 124
***Gunma Prefectural Institute of Public Health and Environmental Sciences, 3-21-19, Iwagami, Maebashi-shi, Gunma 371
A gas-phase electrolytic conductivity detector (GP-ELCD), a new-type detector for GC which was recently developed by D. M. Coulson and was provided by SRI Co. in U.S.A., was applied to the measurement of ten kinds of volatile chlorinated hydrocarbons (VCHC) in environmental samples. The measurement limit of the detector to VCHC was found to be about 0.05 ng under S/N=5, and the relative sensitivities on a molar basis for each compounds of VCHC depends on the number of chlorine atoms in a molecule. However those on a molecular-weight basis are in similar (0.86~1.00 to the sensitivity of carbon tetrachloride). The variations in its sensitivity of it on the same day or on different days are within 5%. The linear dynamic range of GP-ELCD was at least 0.05~100 ng in the tested range. A detector with a portable GC (SRI 9000) was used for the analysis of VCHC in ambient air with the collection method by a charcoal tube, and was confirmed to be capable of measuring the concentration of trichloroethylene and tetrachloroethylene at 1/10 of the Japan Air Quality Standard (Both; 0.2 mg/m3).
Keywords: gas-phase electrolytic conductivity detector; sensitivity; volatile chlorinated hydrocarbons; environmental samples.