BUNSEKI KAGAKU Abstracts

Outbreaks of large-scale poisoning cases that cause of poisoning were not elucidated at the first time, such as the 1998 Wakayama Poisoned Curry Incident. This threatens safe and secure society, and administrative countermeasure against such poisoning cases should be performed appropriately. How and what should we analytical chemists contribute to crisis management in poisoning cases? The author has engaged in the research and development of the analysis, metabolism and toxicity of volatile toxic substances, such as cyanide and related forensic investigation, as well as the training and guidance for examiners of prefectural police headquarter forensic science laboratories. In 1998, the author performed a forensic investigation on serial-poisoning incidents that occurred during the second half of 1998. In this review article, outlines of the poisoning cases and related forensic investigations in which the author was engaged, and the issues in the consequence management are raised. Then, the matters to notice for analytical chemists in engaging in forensic investigations in poisoning cases are stated, especially concerning the strategy for establishing a poison detection-and-identification system, and pitfalls related to postmortem poison alteration.

It is possible to use bacterial living cells as biosensor elements by applying their chemical-sensing systems. A link between the sensing systems and reporter systems, such as firefly luciferase by genetic manipulation, enables an improvement of the specificity and sensitivity to chemicals in such biosensors. We successfully established whole-cell biosensors composed of photosynthetic bacteria as a host strain and their carotenoid synthetic genes as a reporter. In the presence of target chemicals, the color of biosensors changed from yellow to red based on carotenoid conversion in the host cells; this change is obvious by the naked eye without any equipments or additional reagents. In this paper, we introduce procedures to construct carotenoid-based biosensors, the detection of dimethyl sulfide or arsenite by the color change due to carotenoid conversion, and an approach to obtain an obvious color change in a reporter event using green mutants as a host strain of biosensors.

It is emphasized that chemicals related to daily life products, including plastic materials in wide industrial and consumer applications, may have some biological toxicity, such as endocrine-disrupting effects. An association between exposure to endocrine-disrupting chemicals and an increased incidence of human endocrine disease has led to a need for accurate analytical techniques relating the exposure of these compounds to an individual's risk of developing disease. With an understanding of the progressive processes of endocrine-disrupting effects, opportunities for the identification of human exposure of sources and biomarkers reflecting are provided. Therefore, the developments of highly sensitive and reliable analytical methods have been required to evaluate human exposure of the related chemicals for risk assessment. In order to obtain as much information as possible from the limited amount of samples, hyphenated analytical methods for the determination of endocrine-disrupting chemicals, such as bisphenol A, phthalate esters and perfluorochemicals, have been studied by the use of LC/MS and LC/MS/MS. These simple, accurate and reliable methods with high sensitivity have been successfully applied to the trace analysis of biological and environmental samples with the hope of realizing scientific risk assessment of the chemicals derived from daily life products, such as polymer plastic materials in human blood and urine.

For the chiral separation and quantification of L-proline used as a food additive, a selective pretreatment method that uses o-pthalaldehyde (OPA) and 9-fluorenylmethyl chloroformate (FMOC-Cl) was examined, and HPLC/MS with high sensitivity and high selectivity was developed. Primary amino acids, which exist in liquid foods as impurities, were derivatized with OPA, followed by separation from proline with a solid-phase extraction cartridge. The secondary amino acids were converted into FMOC derivatives. Sample cleanup was achieved with this two-step derivatization method, and a selective pretreatment of secondary amino acids became possible. An excellent means to separate the optical isomer of proline was achieved using a chiral column made of a β-cyclodextrin phase in the polar organic phase mode. The average recovery rates of proline from soft drink, infant formula, and vinegar were as high as 80% to 104%. Using this method, proline in liquid food can be separated optically and determined. This method is expected to be of use in determining of the safety of proline used as a food additive.

Phthalate diesters (PDEs) are ubiquitous contaminants in our life. Phthalate monoesters (PMEs) and their glucuronide conjugates are common metabolites of PDEs, which are detectable in sera and urine of humans exposed to PDEs. In animal studies, some PDEs and PMEs are toxicants to the reproductive and developmental systems. Thus, studies about exposure to PDEs and PMEs in human fetus and infants are required. Breast milk is one of the most important resources of nutrition to infants. However, there is significant information about the concentrations of PMEs in human breast milk. We developed a method to determine PMEs in human breast milk by using a liquid chromatograph-tandem mass spectrometer. Breast milk was extracted with ethylacetate/cyclohexane under an acidic condition. The organic phase was dried under an N₂ stream and dissolved in an acetic ammonium buffer. The extract was processed using enzymatic deconjugation of the glucuronidase, followed by solid-phase purification to obtain a test solution. The recoveries and relative standard deviations of PMEs (5.0 ng/mL) fortified in consumer milk were satisfactory, which were 96.3〜103% and less than 5%, respectively. Eleven human milk samples obtained from Japanese women were examined. Monoethylphthalate (median; range, 0.5; 0.3〜1.3 ng/mL), monobutylphthalate (26.0; 1.8〜156), monobenzylphthalate (1.0; 0.7〜74.3), monoethylhexylphthalate (27.9; 4.4〜129) and monoisononylphthalate (1.2; 0.7〜8.7) were detected from all of the samples. This method would be useful for the determination of PMEs in human breast milk.

Histamine in fish sauce was rapidly determined with a single-line flow-injection system having an immobilized histamine oxidase/peroxidase reactor. Hydrogen peroxide produced by histamine oxidase (EC1.4.3.-) reaction was monitored photometrically by using N-ethyl-N-(2-hydroxy-3-sulfopropyl)-3-methoxyaniline and 4-aminoantipyrine as color reagents with peroxidase (EC 1.11.1.7) at 530 nm. The carrier solution was 0.1 M CHES-NaOH buffer (pH 8.0). The reactor was stable for 2 weeks. The detection limit was 3 μM and the range of determination was 10〜1000 μM. The sample throughput was about 20/h without any carryover. The results showed a good correlation with those obtained using a conventional HPLC method.

A simple and reliable method using liquid chromatography-electrospray ionization-mass spectrometry (LC/ESI-MS) has been developed for the determination of 4-nonylphenol (4-NP) and 4-octylphenol (4-OP) in seafood and meat. LC separation was performed on a Cadenza CD-C18 column (100×2 mm i.d.) with a gradient system of 50% acetonitrile (containing 1 mM ammonium acetate and 0.005% acetic acid)-acetonitrile as the mobile phase at a flow rate of 0.2 mL/min. The negative ionization produced molecular related ions: (M−H)⁻, at m/z 205.1 and 219.1 for 4-OP and 4-NP, respectively. The calibration graphs for 4-NP and 4-OP were rectilinear from 0.5 to 50 ng/mL with selected ion monitoring (SIM). The compounds were extracted with methanol, and the extracts were cleaned up on a Isolute Multimode cartridge (500 mg). The method involves enzymatic deconjugation by β-glucuronidase and correction of the stable isotopically labeled internal standard, 4-octylphenol-d type. The recoveries of the compounds from seafood fortified at a level 10 ng/g was 72.1〜89.6%, with high precision. The limits of detection of the compounds in seafood were 0.5〜2 ng/g.

This study revealed that high-energy SRXRF (synchrotron radiation X-ray fluorescence spectrometry) utilizing 75.5 keV X-rays of SPring-8 is a powerful technique for trace elemental analysis of ceramic prints on automotive glasses for forensic examination. Fragments of 99 ceramic prints were collected from automobiles of various manufacturers, types and model years. Their major heavy element-components were found to be either Pb or Bi. Because of recent environment protection movement for lead-free material, there was a tendency of the shift of material from the Pb Type to the Bi Type with years of the production. A utilization of 75.5 keV X-rays as excitation source allowed us to detect trace heavy-elements, such as Sb, La, Ce, Hf and W, as well as relatively light-elements, such as V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr and Mo, in samples using K series of XRF emission lines. XRF intensities of these elements normalized by those of the major heavy-elements (Pb or Bi) became characteristic finger prints, showing the identity of each sample with a size of less than 0.5×0.5 mm². The mean relative standard deviations of the normalized XRF intensities measured for the three fragments of each sample were less than 9.3%. These results show that the ceramic prints on automobile glasses contain rich elemental information for discrimination, and therefore the materials can be important evidence for practical forensic examinations.

An X-ray fluorescence (XRF) technique has been developed for analyses of trace elements in vegetables utilizing an energy-dispersive XRF spectrometer equipped with 3-dimensional polarization optics and secondary targets. Quantitative analyses were optimized with the calibration-curve method and the FP method based on the XRF intensity, normalized by that of Compton scattering. Various trace elements in spinach leaves grown at two major production sites, Gifu and Gunma prefectures, Japan, were successfully quantified by an easy sample-preparation technique over a wide concentration range from a few wt%(e.g. K and Ca) to sub-ppm (e.g. Cd and Ba) level. It was possible to clearly characterize the production locality of the spinach by statistical analysis of the trace characteristic elements, such as Ca, Zn, Br, Rb, Mo, and Ba. In addition, it was found that this XRF technique is suitable for rapid and easy screening analysis of Cd in vegetables at their production sites for the environmental regulation requirements.

Psychrotrophic lactic acid bacteria strains potentially used for the fermentation of meat were characterized by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) using ribosomal proteins as biomarkers. The sample strains of a commercial starter culture (strain D-1001) and 15 similar strains were thought to be Lactobacillus sakei, based on their biochemical properties and the 16S rRNA partial gene sequence. By comparing the mass spectra of cell lysates to the calculated masses of ribosomal proteins of genome-sequenced Lactobacillus sakei 23K, all sample strains were definitely identified as L. sakei. Sample strains were further classified into 4 groups based on the mass differences of the 16 biomarkers selected from ribosomal subunit proteins, which could not be discriminated using the 16S rRNA partial gene sequence analysis.

The rapid identification of the sake spoilage microorganisms (hiochi bacteria) by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) using ribosomal proteins as biomarkers was developed. Ribosomal proteins isolated and purified from five representative hiochi bacteria (Lactobacillus fructivorans, L. hilgardii, L. paracasei subsp. paracasei, L. paracasei subsp. tolerans, and L. rhamnosus) as references were characterized by MALDI-MS. Among the peaks observed both from purified ribosomal protein samples and cell lysates in the range of m/z 6000〜12000, the 15 strongest peaks were selected for each reference hiochi bacteria to make a biomarker peak database. Since the m/z values of several biomarker peaks were identical to each bacteria, rapid discrimination and identification of hiochi bacteria could be performed at the species as well as the subspecies level. This method was then applied for the rapid identification of hiochi bacteria generated in a sake brewery. The m/z values of MALDI mass spectra of the hiochi bacteria sample suggested that this bacteria could be identified as L. paracasei subsp. paracasei or closely-related species.

Isotope dilution techniques were evaluated in order to determine the labile pool of cadmium (Cd) in uncontaminated soils. The techniques included determining the E-value (isotopically exchangeable pool) and isotopic exchange kinetics (IEK). An enriched ¹¹³Cd solution was added to the suspension, and then the ¹¹³Cd/¹¹⁴Cd ratio was monitored at different exchange times. After correcting the spectral interference from concomitant elements, the ¹¹³Cd/¹¹⁴Cd ratio in a soil solution (Cd: 0.1 ng mL⁻¹) could be measured with good precision within RSD 5%. The E_(t)-values increased with time, especially between 1 min and 1 day. After 7 days, it reached 0.11 μg g⁻¹, corresponding to 50% of the total Cd. The decrease rate of the ¹¹³Cd/¹¹⁴Cd ratio in the soil solution could be fitted by the IEK equation. The E_(t)-values estimated by long-term isotopic kinetics (from 1 min to 15 days) were in good agreement with observed values. The E_(t)-values, estimated by short-term isotopic kinetics (＜100 min), were also in good agreement up to 15 days. The IEK technique was applied to evaluating the Cd availability of sewage sludge amended soil. These results suggest that the labile pool of Cd in uncontaminated soils can be estimated by short-term isotopic kinetics.

A new derivatization reagent, which facilitated on-column chiral separation for gas chromatography-mass spectrometry (GC/MS) detection of amphetamine (AP) and methamphetamine (MA), was developed. In general, there are two methods to detect enantiomers using gas chromatography: one method uses a chiral stationary phase column; the other is pretreatment consisting of a reaction with a chiral deriavatization reagent to form a diastereomer. Handling both of them is rather complicated. The reagent, (＋)-α-Methoxy-α-(trifluoromethyl)phenylacetyl pyrazole (MTPA-pyrazole), was synthesized from (＋)-α-methoxy-α-(trifluoromethyl)phenylacetyl chloride and pyrazole. AP and MA were injected with the reagent in the GC/MS system, and were separated as α-methoxy-α-(trifluoromethyl)phenylacetyl derivatives. Ethyl acetate solution {10(w/v)%} of the reagent was reasonably stable, and could be used for the routine analysis of AP and MA from urine samples. The calibration curves of AP and MA in 1 μL AP and MA hexane extract showed linearity in the range of 50〜2500 μM. This method gave good reproducibility from urine, and could be adapted to detect 25 μM of AP extract and 50 μM of MA extract in the scan mode.

A simple and sensitive screening method using bioassay for the simultaneous analysis of antibacterials (penicillins, cephalosporins, macrolides, tetracyclines, aminoglycoside, quinolones, etc.) in meat has been developed. The drugs were extraced with 0.5% metaphosphoric acid-methanol-acetonitrile (6 : 2 : 2), and the extracts were cleaned up on an OASIS HLB cartridge (200 mg). The pulp disk method with Bacillus subtilis ATCC 6633 (pH 6 and 8) and Micrococcus luteus ATCC 9341 (pH 8) as test organisms was employed for assaying the antibacterials. Many antibacterials, except for sulfa drugs, were detected with sufficient sensitivity (0.01〜0.5 μg/mL). The recoveries of typical antibacterials (penicillin G, ampicillin, cefapirin, cefalexin, erythromycin, spiramycin, oxytetracycline, chlortetracycline, streptomycin, dihydrostreptomycin, enrofloxacin and oxolinic acid) from swine muscle and liver fortified at levels of 0.05〜0.5 μg/g were 65〜89%. Therefore, we recommend this proposed screening method for the routine analysis of residual antibacterials in livestock products.

The applicability of liquid chromatography/iontrap tandem mass spectrometry (iontrap LC/MS/MS) to screening for 44 veterinary drugs in livestock foods and fish was examined. Mass spectral acquisition was performed in both the positive and negative modes. In LC separation, a CadenzaCD-C18 column was used with 0.1% formic acid-acetonitrile as the mobile phase. The drugs were extracted from livestock foods and fish with acetonitrile/hexane saturated acetonitrile, and cleaned up by a OasisHLB cartridge. The precursor ion and product ions obtained under the EPI mode were key criteria to confirm the identity of veterinary drugs in samples. The MRM mode was obtained with a sensitive analysis. The iontrap LC/MS/MS technique is useful for screening residual veterinary drugs present at low levels in livestock foods and fish.

The application of LA-ICP-MS (laser ablation inductively coupled plasma mass spectrometry) to the chemical characterization of sheet glass was investigated in order to discriminate samples of different origins. A total of 16 patterned sheet-glass samples with different design and thickness, produced by 3 glass manufacturers in Japan, were used for the analysis. Laser ablation analysis was performed with a 213 nm Nd : YAG laser. The analytical results obtained by LA-ICP-MS were good agreement with those obtained by solution ICP-MS for a solution prepared by acid digestion. The concentrations of trace-elements, such as Co, Rb, Sr, Zr, Ba, La and Ce, which exist as impurities at the ppm level in glass, showed the characteristic composition to each sample, and were useful for forensic discrimination. LA-ICP-MS requires smaller samples and a much shorter sample preparation time than does the solution method; therefore, this method is useful for the actual forensic analysis of glass.

A simple preconcentration method based on the sorption on zinc(II) sulfide has been developed for the determination of dissolved mercury(II) in rainwater. Commercially available zinc(II) sulfide (100 mg) was layered on a membrane filter (47 mm of diameter, 0.2 μm of pore size) after grinding in a mortar for approximately 2 min. When up to 500 mL of sample solutions passed through the zinc(II) sulfide-layered filter at a flow rate of 10 mL min⁻¹ or less, ng levels of mercury(II) in the solutions could be quantitatively collected on the filter. By heating the layered zinc(II) sulfide on a ceramic boat together with the filter, the collected mercury(II) could be vaporized as mercury(0) vapor and determined by atomic absorption spectrometry. The detection limit was 0.9 ng L⁻¹ (3σ, n＝6) when 500 mL of the sample solution was used. The proposed preconcentration method was applicable to the determination of dissolved mercury(II) in rainwater.

In thermal processes, such as combustion and pyrolysis reactions, the development of useful techniques for the real-time monitoring of organic compounds, like dioxin and polycyclic aromatic hydrocarbons (PAHs), has been demanded. Supersonic jet resonance enhanced multi-photon ionization time-of-flight mass spectrometry (Jet-REMPI-TOFMS) has been an effective technique in terms of the molecular selectivity, high sensitivity, and real-time analysis capability of those compounds. In this study, we developed a prototype Jet-REMPI-TOFMS system. We tried to carry out real-time observations of the naphthalene emission behavior for heated coal samples in an inert gas flow using an electric tube furnace. The behavior of naphthalene emission on the coal pyrolysis reaction was different among the types of coal species. For example, one coal sample that is used as a coking material, naphthalene, began to appear from 170°C, previously to the generation of methane and ethane, and finished at above 600°C. It is suggested that naphthalene is formed by breaking the naphthyl group contained in thermally unstable sites of coals.

A simple GC/MS method coupled with solid-phase extraction for the determination of four hydrophilic organic compounds in river water was developed. Target hydrophilic organic compounds were 1,4-dioxane, epichlorohydrin, 2-ethoxyethanol, and N,N-dimethylfolmamide. A 500 mL portion of a water sample spiked with surrogate standards was passed to one C₁₈ cartridge and two activated-carbon cartridges in series. A C₁₈ cartridge was used for to trap coexistent hydrophobic organic compounds, and activated-carbon cartridges were used for the preconcentration of hydrophilic organic compounds. A C₁₈ cartridge was removed and discarded. After elution with dichloromethane and enrichment with a gentle steam of nitrogen, hydrophilic organic compounds were determined by GC/MS. The detection and quantitation limits of hydrophilic organic compounds by the proposed method were 0.013〜0.017 μg/L and 0.034〜0.045 μg/L, respectively. Using the proposed method, the concentrations of hydrophilic organic compounds in river water sampled at 45 sites in Tochigi prefecture were determined. The results show that the range of concentrations of 1,4-dioxane was between ND and 7.5 μg/L; N,N-dimethylfolmamide was between ND and 11 μg/L. Epichlorohydrin and 2-ethoxyethanol were not detected.

The forensic discrimination of photocopied characters was examined by the combination of data, such as morphological observations and elemental analyses by SEM/EDX, resin ingredient analyses by Pyr-GC/MS and microscopic FT-IR, and organic additives analyses by HPLC. As an obtained result, a significant morphological difference was observed between each sample, and also characteristic elements, for instance Si, Fe, Cu and Cr, were detected by EDX analyses. The result obtained from Pyr-GC/MS showed that the utilized resin consisted of a styrene-type resin, and spectra obtained by micro FT-IR analysis; these resins were divided to three groups: a styrene/methylmetacrilate copolymer was used in samples 1 and 2. In contrast with this result, a styrene/acryle/epoxy copolymer resin was used in samples 3 and 4. In order to analyze organic additives, part of character was subjected to an extractor by acetonitrile, and HPLC was conducted. Comparisons of HPLC chromatograms of extractives from a part of the character on the examined four different kinds of photocopies, significant difference were observed between them. The protocol established by this examination could completely discriminate the 4 photocopied materials. This procedure was applied to an actual blackmail case. The character on the blackmail and burned dust of the paper existed in deposited soils in front of the suspect's house; their similar character was clarified by this analytical protocol. This result reinforced an investigation by information provided from a scientific evidence examination.

Sick-building syndrome symptoms associated with indoor air volatile organic compounds, including formaldehyde in new or newly remodeled houses, have been increasingly highlighted, and are known as "sick house syndrome" in Japan. We developed a competition enzyme-linked immunosorbent assay for measuring formaldehyde in serum. The specificity of the antiserum generated with formaldehyde-rabbit serum albumin conjugates and the application to the detection of formaldehyde in serum were evaluated. The antiserum selectively reacted with formaldehyde conjugated to rabbit, human, rat and bovine-serum albumins, but not with unconjugated albumins. The quantitative working range of formaldehyde-human serum albumin conjugates was from 0.5 to 500 ng/well.

The application of trace impurity analysis using synchrotron radiation X-ray fluorescence spectrometry (SR-XRF) was investigated for the forensic discrimination of heated and non-heated sheet glasses. Each of 5 sheet glasses produced by 3 domestic manufacturers was divided into 2 groups, one of which was subjected to RI measurement and elemental analysis by SR-XRF after heating at 764°C for 2 minutes while the other was without heating. All of the heated glasses provided lower RI values than those of non-heated ones. The difference in RI between the heated and non-heated glasses ranged from 0.0012 to 0.0015, which was 6〜7 times larger than the variation of RI within a pane of sheet glass. As a result of the elemental analysis of 5 non-heated glasses by SR-XRF, the X-ray intensities of impurity elements, such as Rb, Sr, Zr, Ba, La and Ce, were found to be considerably different among the different glasses. All of 10 pairs among 5 non-heated glasses could be successfully discriminated by comparisons of 4 kinds of X-ray intensity ratios (SrKα/RbKα, ZrKβ/RbKα, BaKα/CeKα, LaKα/CeKα). No significant difference was recognized between the analytical results of the non-heated glasses and those of heated ones by the t-test with a significance level of 1%. It is concluded that trace impurity analysis using SR-XRF is useful for the correct discrimination of heated and non-heated glass fragments, whereas the comparison of only RI can result in false differentiation.

A method for the on-site estimation of arsenic (As) contamination in soil by solid-phase extraction with a resin based on molecular recognition technology (SPE-MRT) and anodic stripping voltammetry (ASV) using a gold film microelectrode was developed. Optimized pretreatments were carried out as follows: 1 g of soil sample was taken and put into polypropylene test tube containing 33 mL 1 M hydrochloric acid solution, which was heated at 70 degree Celsius for 5 min using graphite block hot plate. As in the sample was extracted by shaking for 1 min using an automatic mini-shaker system. The extract was finally filtered through a 0.45 μm disk PTFE membrane filter. The extracted arsenic was electrodeposited on the gold film carbon microelectrode at −400 mV vs. Ag/AgCl for 1 min and the deposits were stripped at a rate of 5 mV/s to 580 mV vs. Ag/AgCl by using AnaLig^® TE-3, Cu in soil extract was removed with 1 M hydrochloric acid for the determination of As. The method can eliminate Cu interference. The detection limit was 0.5 μg/L in soil extract. The results of voltammograms for As in the extracts from real soil samples were the same level as these obtained by a cross-check method using inductively coupled plasma mass spectroscopy (ICP-MS).

The use of a scanning electron microscope (SEM) for forensic pollen analysis was examined as a preliminary study on pollen samples collected from twenty-seven species in general public areas. Pollen samples were air-dried and coated with gold without any pre-treatment which were conventionally performed to remove oil and dewatering. The shapes of pollen grains were observed at magnification of between ×1500 and ×3000, and sculptures were at ×15000. Samples were grouped into three by aperture types, and subdivided by sculptures as the result of observations. Pollens of different families in the same subdivision were distinguishable from the careful observations of details. Pollens of the same genera were grouped in the same subdivisions. It was clarified that use of SEM without any pre-treatment has a high potential for the forensic discrimination of pollen as evidence.

The discovery of an illegal dumping waste at the boundary between Aomori and Iwate prefectures has led to fear that the water leaching from the waste could be contaminated, and will pollute the downstream branches of the Mabechi river, which is the main source for water distributed to the inhabitants along the river. To clarify this, we monitored the concentrations of arsenic, selenium, cadmium and lead in the streams around the site using an ICP-MS method. These inorganic elements are all trace and toxic elements with standard values of 0.01 mg L⁻¹, above which environmental water is considered to be polluted. The concentrations of these four elements in the streams around the dumping site neither exceeded the standard values nor showed any tendency to increase over the monitoring term. The selenium concentrations in at a site downstream from the plant were, however, always greater than those measured in other sampling sites.

Single fibers containing inorganic anti-microbial agents were investigated by a scanning electron microscope/energy dispersive X-ray microanalyzer (SEM/EDX). In recent years, many types of anti-microbial deodorant products have been commercially available in the field of daily life. In this study, single fibers were targeted because they are likely to be left at crime scenes and/or transferred to a victim as trace evidence. For the reason that the elemental composition of inorganic anti-microbial agents was expected to be different from that of other additives, carbon-coated fiber samples were analyzed by SEM/EDX. As a result, Ag, Ti, P, Zr, etc. were detected, and types of inorganic anti-microbial agents in fiber samples could be estimated. The elemental result and distribution status of anti-microbial agents in fiber could be used as indexes for discrimination, and fiber samples whose infrared spectra were identical could be discriminated.

A gas chromatograph-pulsed discharged detector can be used in three modes, such as a pulsed discharged helium ionization detector (PDHID), a pulsed discharged photo ionization detector (PDPID) and a pulsed discharged electron capture detector (PDECD). In this report, this detector's performance was compared with other detectors, such as GC/MS, GC/AED and GC/ECD. The PDHID and/or PDECD mode of this detector was applied to the detection of explosives-covered petroleum, and tear-gas spray using 2-chloroacetophenone, respectively. For the detection of explosives, simulated experiments prepared with 1 vol%, 0.01 vol% and 0.001 vol% nitroglycerin were added to kerosene. Also, for the detection of tear gas, 100 ppt, 10 ppt and 1 ppt of 2-chloroacetophenone gas as simulated sample were used. In the nitroglycerin/kerosene sample, the detection limits by GC/AED and GC/MS were 1 vol%, but by GC/ECD and GC/PDECD, 0.001 vol% of nitroglycerin was detected without any interference by kerosene. In 2-chloroacetophenone as a tear-gas sample, 0.01 ppt of 2-chloroacetophenone could be detected by GC/ECD and GC/PDECD; this detection limit was 10000-times lower than that of GC/MS. Furthermore, nitrogen and oxygen were also detected by PDHID. By this examination, GC/PDD was considered to be among the useful analytical devices in forensic investigations.

The application of inductively coupled plasma atomic emission spectrometry (ICP-AES) to the determination of trace elements in steel wires was investigated for the forensic discrimination of wires produced by different manufacturers based on comparing the elemental composition. About 50 mg of a wire sample was accurately weighed and dissolved into a mixture of 1 mL of HCl and 1 mL of HNO₃ by heating at 80°C for 30 minutes, followed by dilution to 10 mL after the addition of a Y solution as an internal standard. Five elements (P, Cr, Mn, Ni and Cu) in the solution of samples prepared as described above were determined using standard solutions for calibration containing the same concentration of Y and reagents as the sample solution. The analytical results of the five elements in NIST Standard Reference Material 16f (Steel Basic Open-Hearth) showed satisfactorily good agreement with the certified values, having relative standard deviations from 0.6% for Ni to 1.2% for P. All of 21 pairs among 7 kinds of wire samples could be discriminated by comparing the concentrations of five elements obtained by the present method.

There is increasing concern that heavy metals present in insoluble minerals used as filter aids are eluted during the filtration of liquid food. Therefore, fundamental research was conducted to determine whether such a phenomenon actually takes place. First, material tests of insoluble minerals were performed using fluorescence X-ray analysis. A semi-quantitative analysis of the major elements constituting insoluble minerals revealed that Si content was higher than approximately 70%, while Al, Fe, Na, and Ca were present in relatively large amounts. As, Pb, and Cd were detected in insoluble minerals other than talc. Then, the elution test was performed on liquid-food-simulating solvents used in the manufacturing process. The elution test of Hg, As, Pb, Cr, and Cd using liquid-food-simulating solvents demonstrated that neither Cd nor Hg was detected from various combinations of insoluble minerals and liquid-food-simulating solvents. In the elution test, As, Pb, and Cr were eluted when nitric acid, a strong eluent, was used. On the other hand, heavy metals, such as As and Pb, were eluted when filter aids, such as diatomaceous earth, were used in the manufacture of near-neutral liquid food and liquid food containing organic acids, such as alcoholic beverages and acetic acid. In this study, where food hygiene was the main concern, As was found not to pose any problems. However, since the toxicity of As is dependent on its chemical form, it is necessary to determine the chemical form of eluted As in future studies.