Vol. 4 9, No. 3
March, 2000
Kenichiro Nakashima*
*Graduate School of Pharmaceutical Sciences, Nagasaki University, 1-14, Bunkyo-machi, Nagasaki 852-8521
(Received 11 December 1999)Chemiluminescence (CL) is the emission of light as the result of electronic excitation of the luminescing species by a chemical reaction of a precursor of that species. Many CL mechanisms have been studied and utilized to analyze either the chemiluminogen or other compounds that participate in the CL reaction. Generally, the CL detection methods are known to be highly sensitive and selective. Thus, various kinds of CL reagents, such as luminols, acridinium esters, aryloxalates, dioxetanes, and Ru(bpy)32+, have been developed and their properties as chemiluminogens examined. Enhancement of the CL reactions has also been examined, and several substances such as 4-iodophenol for luminol-peroxidase-hydrogen peroxide CL, pyrimido[5,4-d]pyrimidines for peroxyoxalate CL and quinine for cerium(IV) CL were found to be useful for this aim. During the last couple of decades, many procedures utilizing CL detection have been developed for determining trace amounts of organic and inorganic compounds, including some of which are biologically important. Among the methods, HPLC or immunoassay with CL detection is more popular and applicable in such fields as clinical and environmental chemistry. Various compounds of biological importance have been determined as diagnosis markers. More recently, capillary electrophoresis with CL detection has become a preferred tool for the analysis of biological samples available in small quantities. In this paper, the application and usage of CL detection in a variety of instrumental analyses, with special emphasis on HPLC, is discussed.
Keywords : chemiluminescence; chemiluminescent reagents; mechanism of chemiluminescence; fluorescent labeling reagent; HPLC.
Yuji Sasaki*
*Research Group for Separation Chemistry, Department of Materials Science, Japan Atomic Energy Research Institute, Tokai, Ibaraki 319-1195
(Received 20 October 1999, Accepted 8 December 1999)Chemical species of Y, Eu and actinides were extracted synergically into an organic solvent with 2-thenoyltrifluoroacetone (Htta) and N,N'-dimethyl-N,N'-dihexyl-3-oxapentanediamide (DMDHOPDA) or with N,N'-dimethyl-N,N'-dihexyl-3-thiapentanediamide (DMDHTPDA) and then investigated by an analysis of the distribution ratio of metal ions. Upon certain concentrations of extractants (0.748 mM [DMDHOPDA]+5 mM [Htta] in toluene for Y, Cm and Cf, and 2.8 mM [DMDHOPDA]+0.5 mM [Htta] in toluene for U), it was found that log D had a curvilineal relationship with the pH. Using the results of the relations of log [Htta] vs. log D and log [DMDHOPDA] vs. log D, a slope analysis showed that more than two extraction species existed, i.e., M(DA)2(tta)(X)2, M(DA)(tta)2(X), where M is Cm or Cf, DA is DMDHOPDA, and X- is ClO4-. In the extraction system of DMDHTPDA and Htta, it was confirmed that plural extraction species of Eu, Am, Th and U also existed in the organic solvent of nitrobenzene.
Keywords : synergistic extraction; diamide; 2-thenoyltrifluoroacetone; actinides; extraction species.
Hidenobu Nakao, Hideki Hayashi and Koichi Okita*
*Advanced Material Lab., Japan Chemical Innovation Institute, Tsukuba Research Center D-3, 2-1-6, Sengen, Tsukuba-shi, Ibaraki 305-0047
(Received 15 November 1999, Accepted 14 December 1999)The spectroelectrochemical properties of polyphenazasiline, which contained diphenylamine units bridged by silicon, were studied. These polymers were soluble in common organic solvents, and showed high electrochemical activities. In the form of cast films these polymer films showed various changes in a color tone upon electrochemical oxidation. The spectroelectrochemical properties of polyphenazasiline were also studied for solutions in dichloromethane. As compared with the spectroelectrochemical properties of poly(N-methyldiphenylamine), the effect of a silicon bridge on the electronic structures of polyphenazasilines was considered.
Keywords : polyphenazasiline; π-conjugated polymer; soluble polymer; spectroelectrochemistry.
Toshihiro Shirasaki, Hideyuki Sakamoto*, Yuzuru Nakaguchi and Keizo Hiraki**
*Techno Research Laboratory, Hitachi Science Systems, Ltd., 882, Ichige Hitachinaka-shi, Ibaraki 312-8504
**Department of Chemistry, Faculty of Science and Technology, Kinki University, 3-4-1, Kowakae, Higashiosaka-shi, Osaka 577-8502
An analytical method for the determination of molybdenum in water samples was developed by isotope-dilution/microwave induced plasma mass spectrometry. The optimum analytical scanning conditions of a microwave induced plasma mass spectrometer, the effect of the isobar (98Ru) concentration on the accuracy of the 98Mo/97Mo ratio measurements, the dependency of the molybdenum concentration in a water sample on the RSD of 98Mo/97Mo ratio measurements, and the effect of the matrix-element concentration on the 98Mo/97Mo ratio measurements were investigated by measuring the 98Mo/97Mo ratio. As a results, the RSD of the 98Mo/97Mo ratio measurements was able to be measured within 1.0% when the molybdenum concentration exceeded 10 µg/l. Moreover, it was also noted that an 8-hydroxyquinoline extraction technique coupled with isotope dilution/microwave induced plasma mass spectrometry was useful for determining molybdenum in high-matrix samples. The proposed method was applied to the determination of molybdenum in Trace Elements in Water (NIST SRM 1643c, 1643d), Open Ocean Seawater (NRCC NASS-4), Nearshore Seawater (NRCC CASS-3). The analytical results were in good agreement with the certified values.
Keywords : isotope dilution/microwave induced plasma mass spectrometry; determination of molybdenum; 8-hydroxyquinoline extraction.
Sadao Nakamura, Masahiko Takino* and Shigeki Daishima**
*Kansai branch office, Yokogawa Analytical Systems Inc., 3-3-11, Niitaka, Yodogawa-ku, Osaka 532-0033
**Yokogawa Analytical Systems Inc., 2-11-13, Nakacho, Musashino-shi, Tokyo 180-0006
An analytical method for determining potential endocrine disruptors (2,4-dichlorophenol, pentachlorophenol, bisphenol A (BPA) and 17β-estradiol) by GC/MS with negative-ion chemical-ionization (NICI) has been developed. The target chemicals were derivatized with pentafluorobenzyl bromide (PFBBr) and the NICI of all derivatives produced an intense (M-PFB)- ion as the base peak. A trace analysis of the target chemicals was carried out on GC/MS-SIM using an (M-PFB)- ion. The effect of the reagent gas (methane) flow rate and ion source temperature on the ion abundance was examined for the optimized GC/MS condition. These were determined as follows: reagent gas-flow rate, 2.5 ml/min; ion source temperature, 210°C. The detection limits of the method ranged from 0.4 pg/ml to 12.5 pg/ml. Good linearity of the calibration curve was obtained in the concentration range from 10 pg/ml to 100 ng/ml. The correlation coefficients were >0.9995 for all chemicals. The relative standard deviations of the peak areas of the target chemicals were 2.8~9.3% for 20 pg/ml, 6.2~9.7% for 100 pg/ml and 2.7~8.6% for 1000 pg/ml. The recoveries of the target chemicals from river water spiked with standards at the 10 pg/ml level for 17β-estradiol, 100 pg/ml level for chlorophenols and 1000 pg/ml level for BPA were 91.4~103.3%. The relative standard deviations were from 5.0 to 8.3%. When the detection limits of this method were compared with those obtained by electron ionization (EI) of the trimethylsilylated derivatives, the sensitivities of NICI were 6.5~150 times higher than those of EI.
Keywords : 2,4-dichlorophenol, pentachlorophenol, bisphenol A and 17β-estradiol; GC/MS with negative ion chemical ionization; derivatizing with pentafluorobenzyl bromide; endocrine disruptors; solid-phase extraction.
Keiko Jyonosono, Toshihiko Imato*, Noriyuki Imazumi and Jun-ichi Yagi**
*Department of Chemical Systems and Engineering, Graduate School of Engineering, Kyushu University, 6-10-1, Hakozaki, Higashi-ku, Fukuoka 812-8581
**Lubricants Research Laboratory, Idemitsu Kosan Co., Ltd, 24-4, Anegasakikaigan, Ichihara, Chiba 299-0107
A spectrophotometric FIA method for the determination of the total acid number in a lubricant was proposed, which involved using an acid-base buffer solution prepared with a nonaqueous solvent. This method is based on measurements of the absorbance change of an indicator contained in the acid-base buffer solution, which is generated due to a neutralization reaction of acid in the lubricant with the buffer base. The sample (200 µl or 20 µl) injected into a stream of a nonaqueous solvent, toluene/H2O/2-propanol (52/1/47 v/v%), was merged with a stream of tetrabutylammonium hydroxide (TBAOH) solution; the sample acid was then neutralized with TBAOH. An excess of TBAOH was merged with a stream of tetramethylguanidine (TMG) hydrochloric acid solution containing an indicator (α-naphtholbenzein), which had a similar pKa value to TMG·HCl in the present nonaqueous solvent. The reaction of the excess TBAOH with TMG·HCl gave rise to a composition change of the acid-base buffer solution, TMG-TMG·HCl. Since the indicator, α-naphtholbenzein, behaves similarly to the buffer component, the change in the ratio of TMG·HCl/TMG could be determined by a measurement of the absorbance change of the indicator. The absorbance changes at 680 nm (the wavelength at maximum absorbance of α-naphtholbenzein in basic form) were monitored with a spectrophotometric detector. Peak-shape signals were obtained for acid samples, and a linear relationship between the peak height and the concentration of the samples was found. The sensitivity of the proposed method for several kinds of acids was nearly identical irrespective of the acids. The proposed method was successfully applied to the determination of the total acid number in the lubricant with a sampling rate of 20 hr-1.
Keywords : flow titration; neutralization titration; lubricant; spectrophotometric FIA; pH buffer solution.
Ryoko Chiba*, Hiroyuki Yamazaki, Masuo Umino**, Isao Urayama*** and Akira Tanaka*
*Showa of Pharmaceutical University, 3-3165, Higashitamagawagakuen, machida-shi, Tokyo 194-8543
**Scientific Instrument Division, Tosoh Co., 2743-1, Hayakawa, Ayase-shi, Kanagawa 252-1123
***Toho University School of Medicine, 6-11-1, Omorinishi, Ota-ku, Tokyo 143-8541
The rapid determination of theophylline and antiepileptic drugs(phenobarbital, carbamazepine, phenytoin and valproic acid) in human serum using a combination of a short pretreatment column (TSKprecolumn BSA-ODS/S) and a short analytical column (TSKgel Super-ODS) was investigated. Under the optimized analytical conditions, theophylline and four antiepileptic drugs were eluted within 14 min. The relationship between the sample amount and the peak areas of five drugs indicated good linearity over the range from 1.0 to 500 mg/l (valproic acid) and 0.2 to 110 mg/l (other drugs), respectively. Five drugs from spiked serum were recovered quantitatively. The repeatability and reproducibility of the peak areas of standard and spiked serum were less than 1.6%. The drug concentrations in human serum determined by a enzyme immunoassay method and a column-switching method showed good agreement. Therefore, this column-switching method is very suitable for therapeutic drug monitoring (TDM) in biological fluids.
Keywords : column-switching HPLC; theophylline; antiepileptic drugs; rapid determination; human serum.
Kenji Kurihara, Fumiyo Tanoue and Tadao Shoji*
*Analysis Center, Dainippon Ink & Chemicals, Inc., 631, Sakado, Sakura-shi, Chiba 285-8668
(Received 22 September 1999, Accepted 24 December 1999)Keywords : thermal extraction; gas detector tube; formaldehyde; phosphine; high-frequency heating.
Kenji Kurihara and Fumiyo Tanoue*
*Analysis Center, Dainippon Ink & Chemicals, Inc., 631, Sakado, Sakura-shi, Chiba 285-8668
(Recieved 1 November 1999, Accepted 17 December 1999)Keywords : thermal extraction; GC/MS; high-frequency; antioxidant; transesterification
Hiroshi Ono
Mitsui Mining & Smelting Co., Ltd., Corporate R&D Center, 1333-2, Haraichi, Ageo-shi, Saitama 362-0021
(Awarded by Utsunomiya University dated March 24,1998)Separation and determination methods were studied for the simultaneous determination of trace amounts of multielements in metallic materials. In the first study, the separation and determination of trace Ti, Zr, Mo, Sn and Hf in Ni were studied. Ti, Zr, Mo, Sn and Hf were separated from Ni by extracting into benzene with N-benzoyl-N-phenylhydroxylamine (BPA) and subsequently back-extracted into nitric acid for the determination by ICP-AES or ICP-MS. In the second study, the separation and determination of Cu, As, Sb, Pb and Bi in Ni and that of Cu, Ag and Cd in Zn were studied. Trace amounts of these elements were separated from Ni or Zn by extraction into xylene as diethyldithiocarbamate complexes using diethylammonium diethyldithiocarbamate (DDDC), and then back-extracted into nitric acid for the determination by ICP-AES or ICP-MS. In the third study, the method of anion-exchange separation was studied. Trace amounts of Fe, Cu, Zn, Ga, Mo, Cd, In and Sn were separated from Ni by adsorption on an anion-exchange resin column as their chloro complexes in hydrochloric acid media, and then eluted with nitric acid, followed by determinations with ICP-AES or ICP-MS. As a result, sub µg g-1 levels of multielements in Ni or Zn could be successfully determined by the proposed methods.
(Received Nobember 29, 1999)Keywords : solvent extraction; ion-exchange; ICP-AES; N-benzoyl-N-phenylhydroxylamine; diethylammonium diethyldithiocarbamate.
Hiroshi Yoshihisa
Faculty of Engineering, Gunma University, 1-5-1, Tenjin-cho, Kiryu-shi, Gunma 376-8515
(Awarded by the University of Tokyo, dated March 30, 1998)The nerve and synapse system is known to generate and transmit electric pulses. It is a typical non-linear phenomenon, which is why the oscillating membrane system has been especially studied as artificial models for the nerve and synapse system. A three-phase (W/O/W) liquid-membrane system with a surfactant is known to generate non-linear electric pulses whose periodicity is affected by co-existing chemical compounds. Such a response is similar to that of the synapse system, which transmits biochemical information from detecting organs to the brain in the form of electric pulses.
At first, it was found that the high reproducibility and long-term stability of the observed oscillation in this system were achieved by changing the material as well as the shape of the apparatus. This result indicates that the outer boundary of the W/O interface is involved in forming the oscillation.
Secondly, different modes of oscillation were observed. A decrease in the pH of the aqueous phases was accompanied by the modes. The increased rates of proton concentration in each aqueous phase were found to differ in each mode. Based on these results, a mechanism for the oscillation was proposed, and the phenomenon was simulated by computer based on this mechanism.
Thirdly, a novel multi-phase liquid-membrane system having three aqueous phases with a surfactant was found to exhibit synchronisation of the oscillation like in the nerve transmission system.
(Received 6 December, 1999)Keywords : liquid-membrane oscillation; non-linear oscillation; computer simulation; chemical sensor.
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