Yohei Inaba

National Institute of Public Health, Saitama, Saitama, Japan

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Publications (26)47.63 Total impact

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    ABSTRACT: A nationwide survey of indoor air quality in Japan was conducted using four types of diffusive samplers. Gaseous chemical compounds such as carbonyls, volatile organic compounds (VOC), acid gases, basic gases, and ozone were measured in indoor and outdoor air of 602 houses throughout Japan in winter and summer. Four kinds of diffusive samplers were used in this study: DSD-BPE/DNPH packed with 2,4-dinitrophenyl hydrazine and trans-1,2-bis(2-pyridyl)ethylene coated silica for ozone and carbonyls; VOC-SD packed with Carboxen 564 particles for volatile organic compounds; DSD-TEA packed with triethanolamine impregnated silica for acid gases; and DSD-NH3 packed with phosphoric acid impregnated silica for basic gases. These samplers are small and lightweight and do not require a power source, hence, it was possible to obtain a large number of air samples via mail from throughout Japan. Almost all compounds in indoor air were present at higher levels in summer than in winter. In particular, formaldehyde, toluene, and ammonia were strongly dependent on temperature, and their levels increased with temperature. The nitrogen dioxide concentration in indoor air particularly increased only during winter and was well correlated with the formic acid concentration (correlation coefficient=0.959). Ozone concentrations in indoor air were extremely low compared with the outdoor concentrations. Ozone flowing from outdoor air may be decomposed quickly by chemical compounds in indoor air; therefore, it is suggested that the indoor/outdoor ratio of ozone represents the ventilation of the indoor environment. Copyright © 2014 Elsevier Inc. All rights reserved.
    Environmental Research 01/2015; 137C:364-372. DOI:10.1016/j.envres.2014.12.005 · 3.95 Impact Factor
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    ABSTRACT: In Japan, ultralow-nicotine cigarette brands with ventilation holes on the cigarette filters have been widely marketed to smokers. The use of these cigarette brands leads to compensation smoking. Menthol cigarette brands that have a cooling and numbing effect are also sold. In 2013, smokeless tobacco products similar to the Swedish snus, which is banned for sale in the European Union except in Sweden, were released in Japanese markets. These tobacco products have "toxicity," have a "ventilation filter," are "attractive," and promote "dependence." Tobacco smoke and smokeless tobacco are classified into "Group 1: Carcinogenic to humans" by the International Agency for Research on Cancer (IARC). The purpose of Articles 9 and 10 of the World Health Organization Framework Convention on Tobacco Control (WHO FCTC) is to regulate the contents of tobacco products as well as to regulate tobacco product disclosures. The implementation of some other articles has gradually advanced in Japan. However, that of Articles 9 and 10 is late. Japanese governmental authorities are being urged to immediately implement Articles 9 and 10.
    Nippon Eiseigaku Zasshi (Japanese Journal of Hygiene) 01/2015; 70(1):15-23. DOI:10.1265/jjh.70.15
  • Kanae Bekki, Yohei Inaba, Naoki Kunugita
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    ABSTRACT: The World Health Organization (WHO) Framework Convention on Tobacco Control (FCTC) requires member countries to implement measures aimed at reducing the demand for tobacco products. FCTC article 11 describes the important forms of health communication and packaging regulations. And this article recommends on large pictorial health warnings and encourages more effective forms of disclosure on constituents and emissions. Furthermore, article 11 recognizes the importance of the package as a promotional vehicle for tobacco companies and requires the removal of potentially misleading packaging information, including the terms "light" and "mild." The Conference of the Parties (COP) adopted guidelines for implementation of article 11 on "Packaging and labelling of Tobacco Products". Some countries, such as Canada, the U.S.A., Australia, EU countries etc. positively promoted tobacco control by implementing countermeasures such as the graphic health warning labels and plain packages. These countermeasures showed the significant effects of decreasing smoking rate and preventing smoking initiation in young people. Furthermore, these warning labels were effective for the literally challenged. However, the Japanese government has not implemented these countermeasures, and only limited texts are shown on Japanese tobacco packaging. Therefore, Japan should emulate approaches taken by other countries, and promote the tobacco control policy in accordance with FCTC.
    Nippon Eiseigaku Zasshi (Japanese Journal of Hygiene) 01/2015; 70(1):24-32. DOI:10.1265/jjh.70.24
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    ABSTRACT: Gaseous chemical compounds such as carbonyls, volatile organic compounds (VOC), acid gases, basic gases, and ozone were measured in indoor and outdoor air of 40 houses throughout Sapporo city in the winter (January to March, 2012 and 2013) and summer (July to September, 2012) using four kinds of diffusive samplers. Almost all compounds in indoor air were present at higher levels in the summer than in the winter. The indoor concentrations of acetaldehyde and p-dichlorobenzene exceeded the Health, Labour and Welfare, Japan guideline in three and two houses, respectively. The mean concentrations of formaldehyde were 27 μg m−3 in the summer and 17 μg m−3 in the winter, and showed that the summer concentration was 1.6-fold higher than that in the winter. Nitrogen dioxide was present in extremely high concentrations in the winter, and it was suggested that the sources of nitrogen dioxide in indoor air are kerosene heaters, unvented gas stoves and heaters. Formic acid was generated by combustion because the nitrogen dioxide concentration in indoor air was well correlated with the formic acid concentration (correlation coefficient = 0.947). In outdoor air, the negative correlation between nitrogen dioxide and ozone was observed during the winter. It was suggested that the reaction of nitric oxide and ozone may influence the formation of nitrogen dioxide.
    Bunseki kagaku 01/2015; 64(1):55-63. DOI:10.2116/bunsekikagaku.64.55 · 0.22 Impact Factor
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    ABSTRACT: Electronic cigarettes (e-cigarettes) are advertised as being safer than tobacco cigarettes products as the chemical compounds inhaled from e-cigarettes are believed to be fewer and less toxic than those from tobacco cigarettes. Therefore, continuous careful monitoring and risk management of e-cigarettes should be implemented, with the aim of protecting and promoting public health worldwide. Moreover, basic scientific data are required for the regulation of e-cigarette. To date, there have been reports of many hazardous chemical compounds generated from e-cigarettes, particularly carbonyl compounds such as formaldehyde, acetaldehyde, acrolein, and glyoxal, which are often found in e-cigarette aerosols. These carbonyl compounds are incidentally generated by the oxidation of e-liquid (liquid in e-cigarette; glycerol and glycols) when the liquid comes in contact with the heated nichrome wire. The compositions and concentrations of these compounds vary depending on the type of e-liquid and the battery voltage. In some cases, extremely high concentrations of these carbonyl compounds are generated, and may contribute to various health effects. Suppliers, risk management organizations, and users of e-cigarettes should be aware of this phenomenon.
    International Journal of Environmental Research and Public Health 11/2014; 11(11):11192-11200. DOI:10.3390/ijerph111111192 · 1.99 Impact Factor
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    ABSTRACT: Objective: To determine constituents of fillers and mainstream smoke from Neo Cedar. Methods: Neo Cedar is a second-class over-the-counter (OTC) drug and similar to cigarettes in a number of ways. In particular, the design and usage are very similar to those of cigarettes. For the fillers of the drug, the levels of nicotine, tobacco-specific nitrosamines (TSNA), and heavy metals, and mutagenicity were determined using the methods for cigarette products. For the mainstream smoke, the levels of tar, nicotine, carbon monoxide (CO), TSNA, polycyclic aromatic hydrocarbons (PAH), and carbonyl compounds were also determined using the methods for cigarettes. The mainstream smoke from the drug were collected with a smoking machine using two smoking protocols (ISO and Health Canada Intense methods). Results: The nicotine and total TSNA levels in the fillers of the drug averaged 2.86 mg/g and 185 ng/g, respectively. The nine species of heavy metals were also detected in the fillers of the drug. The levels of nicotine, tar, CO, TSNA, PAH, and carbonyl compounds of mainstream smoke from the drug were higher when determined using the HCI regime than when using the ISO regime. The mutagenicity of the mainstream smoke determined using the HCI regime was also higher than that determined using the ISO regime. Conclusion: In this study, all constituents of Neo Cedar were determined by methods for cigarette products. The drug had a ventilation hole on its filter. Thus, its constituents are different from those determined by the smoking protocols. Neo Cedar users should be careful of higher exposure to the hazardous gases owing to smoking patterns.
    Nippon Eiseigaku Zasshi (Japanese Journal of Hygiene) 01/2014; 69(1):31-8. DOI:10.1265/jjh.69.31
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    ABSTRACT: The tobacco tax in Japan was increased in October, 2010. Subsequently, the quantity of sales of domestic cigarette products decreased temporarily. However, smokers could import cigarettes directly through the internet. Because of the high value of the yen and the low price of foreign cigarettes, an individual could import cigarettes easily; however, the contents and emissions from privately imported cigarettes have not been investigated yet. In this study, we carried out a comparative analysis of domestic and privately imported cigarettes.
    Nippon Eiseigaku Zasshi (Japanese Journal of Hygiene) 01/2014; 69(3):205-10. DOI:10.1265/jjh.69.205
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    ABSTRACT: We developed a simple method for the simultaneous determination of volatile organic compounds (VOCs) and carbonyls in the mainstream cigarette smoke using a sorbent cartridge at ambient temperature without the traditional cryogenic impinger. A sorbent cartridge is installed between intake filter and the pump of the smoking machine. Collection of cigarette mainstream smoke is performed according to the Canadian Intense regime or the ISO regime. As adsorbent, Carboxen 572 (CX-572) is the most suitable for collection of VOCs and carbonyls in the mainstream cigarette smoke. Elution of VOCs and carbonyls from CX-572 is performed by the two-step elution with carbon disulfide and methanol. VOCs are eluted by first elution with carbon disulfide and carbonyls are eluted by second elution with methanol. For VOCs, a portion of eluate is analyzed by gas chromatography-mass spectrometry. For carbonyls, a portion of eluate is derivatized with enriched 2,4-dinitrophenylhydrazine solution and analyzed by high-performance liquid chromatography. Measurement values by CX-572 cartridge method are very close to those obtained by traditional impinger method except for 2-butanone. Impinger methods use 2,4-dinitrophenylhydrazine solution containing 50% water and 2-butanone-DNPhydrazone may be hydrolyzed with water. In the CX-572 method, the hydrolysis of 2-butanone is prevented because the eluate solution contains no water. CX-572 method can measure cigarette smoke resulting from not only one whole cigarette but also from one puff volume because of its high sensitivity and simple operation.
    Journal of Chromatography A 09/2013; 1314. DOI:10.1016/j.chroma.2013.09.019 · 4.26 Impact Factor
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    ABSTRACT: Objective: To measure the nicotine and tobacco-specific nitrosamine (TSNA) contents in whole tobacco from a variety of Japanese domestic cigarette brands and to determine mutagencity. Methods: The test cigarettes were the top ten best selling cigarette brands in Japan in 2006. The nicotine content in whole tobacco was measured by a modified version of the CORESTA Recommended method. The level of TSNA was measured by a modified version of the Health Canada method. Mutagenicity was assessed using the Salmonella typhimurium strains TA100, TA98 and YG1024 with the metabolic activation system (S9mix) by preincubation assays. Results: The nicotine content in the test cigarettes averaged 15.7±1.2 mg/g, and was in the range between 13.7 and 17.2 mg/g. The level of TSNA averaged 1,750 ng/g, and was in the range between 931 and 2,490 ng/g. Mutagenicity was pseudopositive in several samples of the YG1024 tester strain with and without S9mix. Conclusion: The cigarettes brands were categorized into four groups (Ultra-low, Low, Medium, and High) based on the nominal nicotine yield figures printed on the cigarette packets. The nicotine content in whole tobacco of the High group was the highest. However, the level of TSNA of the high group was the lowest. The analyses of hazardous chemical compounds in whole tobacco can contribute to the reduction and regulation of the toxicity of tobacco products.
    Nippon Eiseigaku Zasshi (Japanese Journal of Hygiene) 01/2013; 68(1):46-52. DOI:10.1265/jjh.68.46
  • Bunseki kagaku 01/2013; 62(7):603-609. DOI:10.2116/bunsekikagaku.62.603 · 0.22 Impact Factor
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    ABSTRACT: Carbonyl compounds in E-cigarette smoke mist were measured using coupled silica cartridges impregnated with hydroquinone and 2,4-dinitrophenylhydrazine, followed by high-performance liquid chromatography. A total of 363 E-cigarettes (13 brands) were examined. Four of the 13 E-cigarette brands did not generate any carbonyl compounds, while the other nine E-cigarette brands generated various carbonyl compounds. However, the carbonyl concentrations of the E-cigarette products did not show typical distributions, and the mean values were largely different from the median values. It was elucidated that E-cigarettes incidentally generate high concentrations of carbonyl compounds.
    Analytical Sciences 01/2013; 29(12):1219-1222. DOI:10.2116/analsci.29.1219 · 1.40 Impact Factor
  • Bunseki kagaku 01/2013; 62(3):253-257. DOI:10.2116/bunsekikagaku.62.253 · 0.22 Impact Factor
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    ABSTRACT: A typical method for the measurement of glutaraldehyde (GLA) employs 2,4-dinitrophenylhydrazine (DNPH) to form GLA-DNPhydrazone derivatives. However, this method is subject to analytical errors because GLA-DNPhydrazone is a quaternary bis-derivative and forms three geometric isomers (E-E, E-Z and Z-Z) as a result of the two C[double bond, length as m-dash]N double bonds. To overcome this issue, a method for transforming the C[double bond, length as m-dash]N double bond into a C-N single bond, using reductive amination of DNPhydrazone derivatives, has been applied. The amination reaction of GLA-DNPhydrazones with 2-picoline borane is accelerated with catalytic amounts of acid and is completed within 10 minutes in the presence of 100 mmol L(-1) phosphoric acid. Reduction of GLA-DNPhydrazone by 2-picoline borane is unique and results in the formation of N-(2,4-dinitrophenyl)-1-piperidinamine (DNPPA). NMR and LC-APCI-MS data confirmed the product identification. DNPPA is very stable and did not change when stored for at least four weeks at room temperature. DNPPA has excellent solubility of 14.6 g L(-1) at 20 °C in acetonitrile. The absorption maximum wavelength and the molar absorptivity of DNPPA were 351 nm and 4.2 × 10(4) L mol(-1) cm(-1) respectively. Complete separation between the reduced forms of C1-C10 aldehyde DNPhydrazones, including DNPPA, can be achieved by operating the reversed-phase high-performance liquid chromatograph at 351 nm in gradient mode using a C18 amide column. The reductive amination method for GLA overcomes analytical errors caused by E-E, E-Z and Z-Z geometrical isomers.
    The Analyst 07/2012; 137(18):4274-9. DOI:10.1039/c2an35230c · 3.91 Impact Factor
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    ABSTRACT: OBJECTIVES: Although the relative risk of lung cancer due to smoking is reported to be lower in Japan than in other countries, few studies have examined the characteristics of Japanese cigarettes or potential differences in smoking patterns among Japanese smokers. METHODS: To examine tar, nicotine and carbon monoxide (TNCO) emissions from ten leading cigarettes in Japan, machine smoking tests were conducted using the International Organization for Standardization (ISO) protocol and the Health Canada Intense (HCI) protocol. Smoking topography and tobacco-related biomarkers were collected from 101 Japanese smokers to examine measures of exposure. RESULTS: The findings indicate considerable variability in the smoking behavior of Japanese smokers. On average, puffing behaviors observed among smokers were more similar to the parameters of the HCI protocol, and brands with greater ventilation that yielded lower machine values using the ISO protocol were smoked more intensely than brands with lower levels of ventilation. The smokers of "ultra-low/low" nicotine-yield cigarettes smoked 2.7-fold more intensively than those of "medium/high" nicotine-yield cigarette smokers to achieve the same level of salivary cotinine (p = 0.024). CO levels in expiratory breath samples were associated with puff volume and self-reported smoking intensity, but not with nominal values of nicotine-yield reported on cigarette packages. CONCLUSIONS: Japanese smokers engaged in "compensatory smoking" to achieve their desired nicotine intake, and levels of exposure were greater than those suggested by the nominal value of nicotine and tar yields reported on cigarette packages.
    Environmental Health and Preventive Medicine 07/2012; DOI:10.1007/s12199-012-0293-7
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    ABSTRACT: A diffusive sampling device, the DSD-NH3, has been developed for measurement of ammonia in air. The DSD-NH3 comprises silica gel impregnated with phosphoric acid as the absorbent, a porous sintered polyethylene tube that acts as a diffusive membrane, and a small polypropylene syringe that is used for the elution of analytes from the absorbent. Silica gel impregnated with phosphoric acid is used as absorbent for the DSD-NH3; basic gases in ambient air, including ammonia, are trapped in the DSD-NH3 device by their reaction with phosphoric acid in the sampler to form their corresponding phosphoric acid salts. After collection, the DSD-NH3 samplers are eluted by water. Cations in the eluate, including ammonium ions, are analyzed by ion chromatography. A side-by-side comparison was made with active samplers, demonstrating good correlation (r2 = 0.996). The sampling rate (94.5 ml min−1) was determined from comparison with an active sampling method and sampling rates. The sampling rate is also calculated from the respective molecular weights according to a rule based on Graham’s law. The theoretical sampling rate with the DSD-NH3 is 95.4 ml min−1 and agrees with the experimental value (94.5 ml min−1). Little influence of wind velocity on the sampler was observed. The relative standard deviations for ammonia concentrations were 4.7% with face velocity ranging 0–5.0 m/s.
    Atmospheric Environment 07/2012; 54:629–633. DOI:10.1016/j.atmosenv.2012.02.001 · 3.06 Impact Factor
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    ABSTRACT: Mainstream smoke from cigarettes contains tobacco-specific N'-nitrosamines (TSNAs) listed as Group 1 and 3 carcinogens by the International Agency for Research on Cancer (IARC). Herein, we report on a method of measuring the concentrations of TSNAs in mainstream smoke from the ten top-selling Japanese cigarette brands using an ISO regime by International Organization for Standardization (ISO) and HCI regime of Health Canada. Tar in mainstream smoke was collected on a Cambridge filter pad using a smoking machine. The filter pad was immersed in 40 mL of ammonium acetate (pH 6.8) and shaken for 30 min. The extract was then loaded into a C18 column. After washing with 5 mL of 10% methanol and eluting with 5 mL of 70% methanol, the eluate was concentrated to 1 mL for LC-MS/MS analysis. The concentrations of TSNAs in all cigarette brands were higher when determined using the HCI regime than when determined using the ISO regime. Furthermore, the concentrations of TSNAs measured using both the ISO and HCI regimes showed negligible correlation to the tar and nicotine concentrations indicated on package labels. The cigarette samples used in the study were categorized into four classes: ultralow-, low-, medium-, and high-yield brands, which corresponded to 1, 3-6, 8-10, and 14 mg tar/cigarette, respectively. The concentration of TSNAs in ultralow-yield cigarettes was 210 ng/cigarette, as measured using the HCI regime, which was nearly equal to that in high-yield cigarettes (180 ng/cigarette). Exposure to TSNAs from mainstream smoke from ultralow-yield cigarettes is comparable to that from high-yield cigarettes. To properly evaluate the risk of smoking, not only the concentrations of tar and nicotine but also those of other chemicals, including TSNAs, should be printed on package labels.
    Nippon Eiseigaku Zasshi (Japanese Journal of Hygiene) 05/2012; 67(3):423-30. DOI:10.1265/jjh.67.423
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    ABSTRACT: The most widely used method for measuring carbonyl compounds in air is 2,4-dinitrophenylhydrazine (DNPH) derivatization followed by high-performance liquid chromatography (HPLC). However, substantial negative interference caused by the presence of ozone in air has been reported. To avoid the influences of ozone, a potassium iodide scrubber (KI-scrubber) is commonly used. However, when air sampling using a DNPH-cartridge and a KI-scrubber is performed under conditions of high humidity, moist potassium iodide in the KI-scrubber traps carbonyls before they reach the DNPH-cartridge. Moreover, wet KI reacts with I(2) to form KI(3) and this oxidative reagent moves to the DNPH-cartridge and destroys the DNPH and DNPhydrazone derivatives. In order to alleviate these problems, new ozone scrubbers (BPE-scrubber, HQ-scrubber) have been developed. BPE-scrubber and HQ-scrubber consist of silica gel particles impregnated with trans-1,2-bis-(2-pyridyl) ethylene (BPE) and hydroquinone (HQ), respectively. BPE reacts with ozone to form pyridine aldehyde and HQ reacts with ozone to form benzoquinone. The amounts of reducing agent in silica gel (130 mg) for ozone scrubber are 1% (w/w) for BPE-cartridge; 0.2% (w/w) for HQ-scrubber. These scrubbers can be used in air containing 140 μg/m(3) of ozone for 24h at a flow rate of 200 mL/min. When the relative humidity exceeded 80%, KI in the KI-scrubber was gradually moistened and changed to yellow in color. Peak abundance of formaldehyde, acetaldehyde and acetone DNPhydrazones was diminished to 25%, 15%, and 2%, respectively, compared with the BPE-scrubber or HQ-scrubber. When using a BPE-scrubber or HQ-scrubber, decomposition of DNPH and DNPhydrazones was not observed at a wide range of relative humidities (3-97%).
    Journal of Chromatography A 03/2012; 1229:293-7. DOI:10.1016/j.chroma.2012.01.062 · 4.26 Impact Factor
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    ABSTRACT: A new diffusive sampling method for the simultaneous determination of ozone and carbonyls in air has been developed. In this method, silica gel impregnated with a mixture of trans-1,2-bis(2-pyridyl)ethylene (2BPE) and 2,4-dinitrophenylhydrazine (DNPH) is used as the absorbent; further, a porous sintered polyethylene tube (PSP-diffusion filter), which acts as a diffusive membrane, and a small polypropylene syringe (PP-reservoir) for elution of the analytes from the absorbent are used. The carbonyls present in air react with DNPH in the absorbent to form hydrazone derivatives. Concurrently, ozone in the air reacts with 2BPE to form pyridine-2-aldehyde, which immediately reacts with DNPH to form a pyridine-2-aldehyde hydrazone derivative. All the hydrazones derived from airborne carbonyls, including pyridine-2-aldehyde (formed from ozone), are completely separated and analyzed by high-performance liquid chromatography. The sampling rates of ozone (44.6 mL min(-1)) and formaldehyde (72.0 mL min(-1)) are determined by comparison with the rates obtained in an active sampling method. The sampling rates of other carbonyl compounds are calculated from the respective molecular weights according to a rule based on Graham's law. The calculated sampling rates agree with the experimental values. The DSD-BPE/DNPH method is advantageous because it is simple and allows for the simultaneous analysis of ozone and carbonyls.
    Analytica chimica acta 04/2011; 691(1-2):119-24. DOI:10.1016/j.aca.2011.02.048 · 4.52 Impact Factor
  • Bunseki kagaku 01/2011; 60(10):791-797. DOI:10.2116/bunsekikagaku.60.791 · 0.22 Impact Factor
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    ABSTRACT: Derivatization of carbonyl compounds with 2,4-dinitrophenylhydrazine (DNPH) is one of the most widely used analytical methods. In this article, we highlight recent advances using DNPH provided by our studies over past seven years. DNPH reacts with carbonyls to form corresponding stable 2,4-DNPhydrazone derivatives (DNPhydrazones). This method may result in analytical error because DNPhydrazones have both E- and Z-stereoisomers caused by the CN double bond. Purified aldehyde-2,4-DNPhydrazone demonstrated only the E-isomer, but under UV irradiation and the addition of acid, both E- and Z-isomers were seen. In order to resolve the isometric problem, a method for transforming the CN double bond of carbonyl-2,4-DNPhydrazone into a C-N single bond, by reductive amination using 2-picoline borane, has been developed. The amination reactions of C1-C10 aldehyde DNPhydrazones are completely converted into the reduced forms and can be analyzed with high-performance liquid chromatography. As a new application using DNPH derivatization, the simultaneous measurement of carbonyls with carboxylic acids or ozone is described in this review.
    Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 10/2010; 879(17-18):1282-9. DOI:10.1016/j.jchromb.2010.09.028 · 2.69 Impact Factor