Eiichi Mikami

Aichi Prefectural Institute of Public Health, Nagoya, Aichi, Japan

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Publications (23)16.91 Total impact

  • Tsutomu Ohno · Eiichi Mikami · Hisao Oka
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    ABSTRACT: We performed identification tests of the main components (ginsenoside-Rg1, gentiopicroside, puerarin, geniposide, schizandrin, and [6]-gingerol) of the following crude drugs from the Japanese Pharmacopoeia, 14th edition (JP14): ginseng, red ginseng, gentian, Japanese gentian, pueraria root, gardenia fruit, schisandra fruit, and ginger). The identification was carried out with reversed-phase thin-layer chromatography using water, acetonitrile, methanol, 2-butanone, and n-hexane as developing solvents. A single spot could be separated from other components (Rf value: 0.44–0.59). In addition, spectral information could be simultaneously obtained by scanning densitometry. Thus, the main components of crude drugs in the JP14 could be identified by this method simply, rapidly, and accurately.
    No preview · Article · Apr 2006 · Journal of Natural Medicines
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    ABSTRACT: We performed identification tests of aristolochic acid in Xixin, Mutong, Muxiang, and Fangji by reversed-phase TLC/scanning densitometry using aristolochic acid I as a marker compound. The developing solvents used were: 1) acetonitrile/methanol/ water mixture solution (3 : 1 : 1) and 11) 2-butanone/ methanol/sodium sulfate(1 -> 20) mixture solution (2 : 1 : 1). The Rf value of aristolochic acid I was 0.54 using the I system and 0.57 using the 11 system. The maximum absorption wavelengths of aristolochic acid I observed by scanning densitometry were 254 and 325 nm.
    Preview · Article · Feb 2006 · Journal of health science
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    ABSTRACT: A high performance liquid chromatography (HPLC) method for the simultaneous analysis of the seven benzodiazepines (BZDs), oxazolam, nitrazepam, oxazepam, tofisopam, triazolam, clotiazepam and diazepam (DIA) is presented for application in the screening examination of dietary supplements as adulterants. Samples were analyzed after extraction with methanol. HPLC analysis was performed with on a column of Wakosil 5C18 (4.6 x 150 mm, 5 mu m) with the mobile phase consisting of 1-heptanesulfonic acid sodium salt 5 mM dissolved in water/acetonitrile 1000 ml (13 : 7, v/v), adjusted with phosphoric acid to pH 2.4. The column eluent was monitored with a photodiode array detector, and the quantitative analysis of BZDs was performed at 225 nm. The calibration curves of the seven BZDs showed good linearity and the correlation coefficients were better than 0.999 in all cases. When this procedure was applied to commercial supplements, an DIA-adulterated capsule-type supplement was detected. Finally, DIA was identified and determined using a combination of three different analytical methods: HPLC/photodiode array, thin-layer chromatography (TLC), and LC/MS. DIA was present at a concentration of 1.9 mg/capsule. The procedure described here can provide a broad analysis in a single run within 17 min and is available for the screening of seven BZDs in adulterated supplements with minimal sample preparation.
    No preview · Article · Jun 2005 · Journal of health science
  • Eiichi Mikami · Tsutomu Ohno · Hisao Oka · Hiroo Ishihara

    No preview · Article · Jan 2005
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    ABSTRACT: Thyroxine (T4), one of the thyroid hormones, in adulterated dietary supplements was analyzed using two different methods; enzyme-linked immunosorbent assay (ELISA) and LC/MS. To release T4 from thyroglobulin, samples were first hydrolyzed with proteolytic enzyme, and then the supernatant was diluted and directly analyzed using a commercial free T4 ELISA kit for diagnostic discrimination. In contrast, T4 was extracted with ethyl acetate from the supernatant, and then ethyl acetate layer was evaporated. The residue was dissolved in the mobile phase and analyzed by LC/MS with electrospray ionization (ESI) interface under positive ion mode. These methods were applied to the analyses of 13 dietary supplements advertised as weight reducers. T4 was detected in four of the samples and the analytical results by ELISA agreed well with those obtained by LC/MS. The ELISA technology described here is available for the screening of T4 in adulterated supplements.
    Preview · Article · Dec 2003 · Journal of health science
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    Tsutomu Ohno · Eiichi Mikami · Hiroshi Matsumoto
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    ABSTRACT: A simple and rapid analytical method of oil-soluble coal tar dyes in cosmetics was established using re-versed-phase TLC/scanning densitometry. Eleven kinds of oil-soluble coal tar dyes were able to be sepa-rated completely on reversed-phase TLC plates by the complementary use of 2 solvent systems. The solvent systems were A; n-hexane/2-butanone solution (5 : 1, v/v), solvent system B; acetonitrile/methanol solution (5 : 1, v/v). Then we measured visible absorption spec-tra of spots developed on the reversed-phase TLC plates by scanning densitometer to identify these coal tar dyes. The proposed method was successfully ap-plied to the identification of oil-soluble coal tar dyes in commercial cosmetics.
    Preview · Article · Oct 2003 · Journal of health science
  • Eiichi Mikami · Tsutomu Ohno · Hiroshi Matsumoto
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    ABSTRACT: An easily available, simultaneous identification/determination procedure for phentolamine (PHE) and sildenafil (SIL) in adulterated dietary supplements was established by using a combination of three different analytical methods; thin-layer chromatography (TLC), liquid chromatography-mass spectrometry (LC/MS) and a high-performance liquid chromatography (HPLC)/photo-diode-array. The sample solution for TLC was applied to silica gel 60 F(254) plates with chloroform/ammonia solution (28)/methanol (70:5:3, lower layer) and chloroform/diethylamine/methanol (15:3:2) as the developing solvent. Spots were located under UV radiation at 254 nm. Mass spectra of PHE and SIL by LC/MS were investigated with electrospray ionization (ESI) interface, under both positive and negative ion mode. The HPLC analysis was performed on a column of Wakosil 5C18 (4.6 mm x 150 mm, 5 microm) with water/methanol/acetonitrile/triethylamine (580:250:170:1) adjusted with phosphoric acid to pH 3.0 as the mobile phase, and the effluent was monitored with a photo-diode-array detector. Quantitative HPLC analysis of PHE and SIL were detected at 280 nm. When this procedure was applied to commercial soft drinks, PHE and SIL were identified and determined at a concentration of 17 mg PHE and 44 mg SIL per bottle, respectively. The procedure described here is available for the screening of PHE and SIL in adulterated supplements.
    No preview · Article · Jan 2003 · Forensic Science International
  • E Mikami · T Goto · T Ohno · H Matsumoto · M Nishida
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    ABSTRACT: A high-performance liquid chromatographic (HPLC) method for simultaneous determination of dehydroacetic acid (DHA), benzoic acid (BA), sorbic acid (SOA) and salicylic acid (SA) was developed for application to cosmetic products. Isocratic reversed-phase HPLC was employed for quantitative analysis using tetra-n-butylammonium (TBA) hydroxide as an ion-pair reagent. Cosmetic samples were purified by solid-phase extraction using Bond-Elut SI cartridges. Four acidic preservatives were eluted with methanol from cartridges. The HPLC assay was carried out using TSK gel ODS-80TM column (5 microm, 150 x 4.6 mm I.D.). The mobile phase consisted of a mixture of water and methanol (65:35, v/v) containing 2.5 mM TBA hydroxide adjusted with phosphoric acid to pH 7.0. The calibration curves of these preservatives showed good linearity with UV detection (235 nm). The correlation coefficients were better than 0.999 in all cases. The lower limits of detection (defined as a signal-to-noise ratio of about 3) were approximately 2.5 ng for DHA, 4.0 ng for BA, 2.0 ng for SOA and 5.5 ng for SA. The procedure described here is simple, selective and is suitable for quality control of finished cosmetic products.
    No preview · Article · May 2002 · Journal of Pharmaceutical and Biomedical Analysis
  • Tomomi Goto · Eiichi Mikami · Tsutomu Ohno · Hiroshi Matsumoto
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    ABSTRACT: A high-performance liquid chromatographic (HPLC) method for the simultaneous analysis of triamterene, trichlormethiazide, furosemide and spironolactone is presented for application in the examination of health food supplements advertising weight reduction and in the analysis of pharmaceuticals. The HPLC assay was performed under gradient conditions using a Wakosil ODS 5C18 column (5 microns, 150 x 4.6 mm i.d.). The mobile phase consisted of a gradient program with a mixture of water and acetonitrile containing 0.1% triethylamine adjusted with phosphoric acid to pH 3.0: from 0 to 6 min, 15% acetonitrile; from 6 to 20 min, linear gradient from 15 to 50% acetonitrile; and from 20 to 40 min, 50% acetonitrile. The column effluent was monitored from 0 to 20 min at 260 nm and from 20 to 40 min at 235 nm. The calibration curves of the four drugs showed good linearity and the correlation coefficients were better than 0.999 in all cases. The lower limits of detection were approximately 40 ng for each drug. Commercially available health food supplements and pharmaceuticals were analyzed after extraction with a mixture of methanol and acetic acid (99:1). The procedure described here is suitable for the screening of four diuretic drugs in adulterated supplements and for the quality control of pharmaceuticals with minimal sample preparation.
    No preview · Article · May 2002 · Journal of the Food Hygienic Society of Japan (Shokuhin Eiseigaku Zasshi)
  • E Mikami · T Goto · T Ohno · H Matsumoto · M Nishida
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    ABSTRACT: A high-performance liquid chromatographic (HPLC) method for simultaneous determination of naproxen (NAP), nabumetone (NAB) and its major metabolite, 6-methoxy-2-naphthylacetic acid (6-MNA), was developed for the application to pharmaceuticals and human urine. Isocratic reversed-phase HPLC was employed for quantitative analysis using triethylamine and 1-heptanesulfonic acid sodium salt (HSA) as ion-pair reagents. Urine samples were purified by solid-phase extraction using Bond-Elut Certify II cartridges containing reversed-phase and anion exchange functionalities. The HPLC assay was carried out using a Wakosil ODS 5C18 column (5 microm, 150 x 4.6 mm, i.d.). The mobile phase consisted of 0.5 g of HSA dissolved in 1,000 ml of a mixture of acetonitrile, water and triethylamine (500:500:1, v/v) adjusted with phosphoric acid to pH 3. The calibration curves of NAP and NAB showed good linearity in the concentration range 32-160 microg/ml with UV detection (270 nm) for pharmaceuticals. In the low concentration ranges (8-96 ng of NAP per ml, 24-288 ng of NAB per ml and 5.6-67.2 ng of 6-MNA per ml), the calibration curves were also obtained with fluorimetric detection (excitation 280 nm, emission 350 nm) for biological fluids. The correlation coefficients were better than 0.999 in all cases. The lower limits of detection (defined as a signal-to-noise ratio of about 3) were approximately 0.3 ng for NAP, 1.5 ng for NAB and 0.2 ng for 6-MNA. The procedure described here is rapid, simple, selective, and is suitable for routine analysis of pharmaceuticals and pharmacokinetic studies in human urine samples.
    No preview · Article · Nov 2000 · Journal of Pharmaceutical and Biomedical Analysis
  • E Mikami · T Goto · T Ohno · H Matsumoto · K Inagaki · H Ishihara · M Nishida
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    ABSTRACT: A high-performance liquid chromatographic (HPLC) method for simultaneous determination of mefenamic acid (MFA), flufenamic acid (FFA) and tolfenamic acid (TFA) is presented for application to pharmaceuticals and human urine. Isocratic reversed-phase HPLC was employed for quantitative analysis using tetra-pentylammonium bromide (TPAB) as an ion-pair reagent. Urine samples were purified by solid-phase extraction using a silica-based strong anion-exchanger, Bond-Elut SAX cartridge. The HPLC assay was carried out using a Wakosil ODS 5C18 column (5 microm, 150x4.6 mm I.D.). The mobile phase consisted of 1.9 g of TPAB dissolved in 1:1 of a mixture of acetic acid-sodium acetate buffer solution, pH 5.0, and acetonitrile (11:9, v/v). The calibration curves of MFA, FFA and TFA showed good linearity in the concentration range of 33-167 microg/ml with a wavelength of 280 nm for pharmaceuticals, and in the low concentration range (1.7-30.1 microg/ml) with a wavelength of 230 nm for biological fluids. The correlation coefficients were better than 0.9999 in all cases. The lower limits of detection (defined as a signal-to-noise ratio of about 3) were approximately 2 ng for MFA, 3.5 ng for FFA and 2.5 ng for TFA. The procedure described here is rapid, simple, selective and is suitable for routine analysis of pharmaceuticals and pharmacokinetic studies in human urine samples.
    No preview · Article · Aug 2000 · Journal of chromatography. B, Biomedical sciences and applications
  • E. Mikami · T. Goto · T. Ohno · Y. Miyazaki
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    ABSTRACT: Rapid, accurate and reliable high performance liquid chromatographic methods for the determination of non-steroidal anti-inflammatory drugs epirizole and tiaramide in pharmaceutical preparations were developed using triethylamine, a modifying agent to the mobile phase. Extraction was carried out with methanol-water (1:1,v/v) after grounding tablet and granule preparations. The methods utilized reversed phase C18 column, UV monitoring at 250 nm, ethyl p-hydroxybenzoate as an internal standard for epirizole, and at 295 nm, methyl p-aminobenzoate as an internal standard for tiaramide. Regression analyses of three standard plots in concentration ranges of 0.05–0.4 mg/mL for epirizole and 0.18–1.44 mg/mL for tiaramide gave respective correlation coefficients >0.99998 and >0.99997. Relative standard deviations of the slopes were 0.180% and 0.888%, respectively. Percentage recoveries of these compounds for four commercially available drugs ranged between 99.06 and 103.14 and between 99.15 and 99.71 of the labeled amounts of epirizole and tiaramide, respectively. The methods were successfully applied to determine contents of epirizole and tiaramide in marketed drugs.
    No preview · Article · Mar 2000 · Journal of Liquid Chromatography & Related Technologies
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    ABSTRACT: The purity test of the Japanese Pharmacopoeia Absorbent Gauze for fluorescent whitening agents is regulated to perform by a method of irradiating the gauze with ultraviolet rays in a dark place. This method has been reported to have a difficulty in detecting the existence of fluorescent whitening agents in several cases. We, therefore, tried to establish a method to examine the existence of fluorescent whitening agents using physical and chemical methodologies. After cutting the Japanese Pharmacopoeia Absorbent Gauze samples in small pieces, fluorescent whitening agents were extracted by 30% pyridine solution at 100°C for 30 min. We analysed the fluorescent agents using reversed phase TLC, spectrofluorophotometer and HPLC with a fluorescence detector using 8 standard fluorescent whitening agents as controls. Conditions of reversed phase TLC: plate, RP-18W (Merck); solvent system, A) acetonitrile-water (1:4), B) acetonitrile-methanol-water (3:3:10), C) methyl ethyl ketone-methanol-water (1:1:1). Conditions of HPLC with fluorescence detection: column, Wakosil 5C18 (i.d. 4.6 x 150 mm); mobile phase, 0.01M ammonium acetate-acetonitrile (7:3); flow rate, 1.0 ml/min; injection volume, 20 μl; detections, fluorescence detector (excitation 345 nm and emission 435 nm).
    No preview · Article · Oct 1998 · Japanese Journal of Toxicology and Environmental Health
  • Yuko Ito · Eiichi Mikami · Tsutomu Ohno · Junko Hayakawa
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    ABSTRACT: When the content of methanol in certain types of waterproofing aerosol products was determined according to the official method for household products containing harmful substances, the existence of an interfering substance in the products was found. The interfering substance was identified to be tert-butanol by GC-MS. In order to avoid this interference, we developed a simple headspace (HS)-gas chromatographic (GC) method. For this method, one gram of the sample sprayed into a 200 ml flask under ice cooling was weighed into a centrifugal tube. Each 10 ml of water and chloroform was added to the centrifugal tube. After shaking vigorously and centrifuging (3500 rpm, 5 min), 0.5 g of the aqueous layer was weighed into a 24 ml bottle. The bottle was incubated for 30 minutes at 25°C and then 50μl of the HS gas was injected into a GC with a fused silica capillary column coated with methyl phenyl cyanopropyl silicone. The proposed method was successfully applied to the screening analysis of methanol in 70 kinds of commercial household aerosol products.
    No preview · Article · Jan 1996 · Japanese Journal of Toxicology and Environmental Health
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    ABSTRACT: A simple and rapid analysis of coal tar dyes in cosmetics and foods was established using reversed phase TLC/scanning densitometry. Forty-five kinds of coal tar dyes were able to be separated completely on reversed phase TLC plates by the complementary use of 4 solvent systems. Solvent system A: acetonitrile-methanol-5% aqueous sodium sulphate solution (3:3:10, v/v), solvent system B: methyl ethyl ketone-methanol-5% aqueous sodium sulphate solution (1:1:1, v/v), solvent system C; acetonitrile-methanol-5% aqueous sodium sulphate solution (1:1:1, v/v), solvent system D; acetonitrile-dichloromethane-5% aqueous sodium sulphate solution. (10:1:5, v/v). The we measured visible absorption spectra of coal tar dyes on the developed reversed phase TLC plates by scanning densitometry to identify these coal tar dyes. The proposed method was successfully applied to the identification of coal tar dyes in commercial products.
    No preview · Article · Jan 1996 · Japanese Journal of Toxicology and Environmental Health
  • Sadaji. Yamada · Naoki. Noda · Eiichi. Mikami · Junko. Hayakawa
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    ABSTRACT: Methylation with ethereal diazomethane in THF was applied to detect cochineal color by TLC. A reddish orange spot at R(f) 0.75 on a silica gel plate developed with chloroform-methanol-water (65:35:10, lower phase) as a solvent was derived from all of the cochineal color preparations when they were methylated. The chemical structure of the spot component employed as indicator compound of cochineal color was characterized as 3,6-di-O-methylcarminic acid methyl ester by physicochemical analysis, UV-vis, IR, H-1 and C-13 NMR, and MS. The cleanup of the crude extract from food product was carried out on a reversed-phase cartridge. The improved analytical procedure for individual food product was accurate, as results of recovery checks (91.2 % for a jelly and 89.8 % for a milk beverage). Indicator compound was observed from 23 of 65 food products analyzed by TLC, and its concentrations ranged from 0.9 to 137.7 mug/g by HPLC analysis.
    No preview · Article · Jul 1993 · Journal of Agricultural and Food Chemistry
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    ABSTRACT: Octyltin compounds were detected from diaper covers by thin layer chromatography using 0.1% pyrocatechol violet solution as a spray reagent, and identified as tri-and di-n-octyltin (TOT and DOT, respectively) species by gas chromatography-mass spectrometric analysis after derivatization to tetrasubstituted organotins with propyl magnesium bromide. TOT and DOT were determined by flame photometric detection-gas chromatography. Amounts of octyltin compounds found in three diaper covers were 67.1, 97.6, and 140.1 μg/g of TOT (as its chloride) and 405.5, 579.8, and 819.2 μg/g of DOT (as its dichloride).
    No preview · Article · Jan 1991 · Japanese Journal of Toxicology and Environmental Health
  • S Yamada · N Noda · E Mikami · J Hayakawa · M Yamada
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    ABSTRACT: A new method has been proposed for detection of lac color in food. Lac color is a natural color additive derived from a secretion of the insect Coccus Laccae (Laccifer lacca Kerr). It is extracted from food with methanolic oxalic acid and eluted from a column of Amberlite XAD-2 with the same solvent. The fraction containing the lac color is treated with diazomethane to produce 2 reddish-orange markers. The marker species in the reaction mixture are detected by both thin-layer chromatography and reverse-phase liquid chromatography.
    No preview · Article · Jan 1989 · Journal - Association of Official Analytical Chemists
  • Eiichi Mikami · Sadaji Yamada · Junko Hayakawa · Masuo Yamada
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    ABSTRACT: A method was described for quantitative analysis of glycyrrhizin in cosmetic lotions and creams. Glycyrrhizin was separated from the cosmetic base and other ingredients by bi-layer (upper ; celite, lower ; silica gel) column chromatography with methanol containing 0.5% acetic acid. The eluate was washed with n-hexane. The methanol layer was concentrated in vacuo and determined by high-performance liquid chromatography (HPLC) on Develosil ODS using a mobile phase of acetonitrile-1% acetic acid (35 : 65). Methyl salicylate was employed as an internal standard. Recoveries of glycyrrhizin obtained from model cosmetics were more than 96% and coefficients of variation were less than 2.2%. This method with clean-up procedure on bi-layer column chromatography was much suitable for the determination of glycyrrhizin in cosmetic lotions and creams.
    No preview · Article · Jan 1988 · Japanese Journal of Toxicology and Environmental Health

  • No preview · Article · Jan 1986 · Japanese Journal of Toxicology and Environmental Health