Analysis of exhaled breath from smokers,passive smokers and non‐smokers by solid‐phase microextraction gas chromatography/mass spectrometry

In this study, 38 samples of expired air were collected and analyzed from 20 non‐smoking volunteers, four passive smokers and 14 smokers (21 women and 17 men). Measurements were carried out using solid‐phase microextraction (SPME) as an isolation and preconcentration technique. The determination and identification were accomplished by gas chromatography coupled with mass spectrometry (GC/MS). Our data showed that ca 32% of all identified compounds in the breath of healthy non‐smokers were saturated hydrocarbons. In the breath of smoking and passive smoking volunteers hydrocarbons were predominant, but also present were more exogenous analytes such as furan, acetonitrile and benzene than in the breath of non‐smokers. Acetonitrile, furan, 3‐methylfuran, 2,5‐dimethylfuran, 2‐butanone, octane and decane were identified in breath of smoking and passive smoking persons. Copyright © 2008 John Wiley & Sons, Ltd.     

Urinary metabolic profiling of volatile organic compounds in acute exposed volunteers after an oil spill in Republic of Korea

The Herbei Spirit oil spill occurred in western Korea. A large number of people who participated in the cleanup tasks of the contaminated area were exposed to crude oil component. We developed a method to monitor volatile organic compound (VOC) metabolites in urine, and evaluate the acute exposure caused by the oil spill in exposed volunteer workers (n = 100, 20.7 ± 2.1 years, mean ± SD). Acidified urine samples were extracted by SPE, derivatized with trimethylsilyl, and analyzed using gas chromatography–mass spectrometry. Calibration curves were found to be linear from 3 to 1000 ng/mL (r² > 0.993). Accuracy was over 82.4%, and precision was less than 24.8%. Using this method, the VOC metabolites, except hippuric acid, were present at higher levels in the urine samples of volunteers after cleanup work. The levels of mandelic acid (MA) and trans,trans‐muconic acid (t,t‐MU) were increased significantly (p < 0.001). The exposure effect was greater in women than in men. The effect of smoking was analyzed in all exposed and non‐exposed groups, with non‐smokers showing increased MA and t,t‐MU levels related to exposure. The present method was reliable to determine VOC metabolites in urine and could be useful for biomonitoring of acute exposure effects of VOCs. Copyright © 2009 John Wiley & Sons, Ltd.     

Evaluation of potential breath biomarkers for active smoking: assessment of smoking habits

Different compounds have been reported as biomarkers of a smoking habit, but, to date, there is no appropriate biomarker for tobacco-related exposure because the proposed chemicals seem to be nonspecific or they are only appropriate for short-term exposure. Moreover, conventional sampling methodologies require an invasive method because blood or urine samples are required. The use of a microtrap system coupled to gas chromatography–mass spectrometry analysis has been found to be very effective for the noninvasive analysis of volatile organic compounds in breath samples. The levels of benzene, 2,5-dimethylfuran, toluene, o-xylene, and m- p-xylene have been analyzed in breath samples obtained from 204 volunteers (100 smokers, 104 nonsmokers; 147 females, 57 males; ages 16 to 53 years). 2,5-Dimethylfuran was always below the limit of detection (0.005 ppbv) in the nonsmoker population and always detected in smokers independently of the smoking habits. Benzene was only an effective biomarker for medium and heavy smokers, and its level was affected by smoking habits. Regarding the levels of xylenes and toluene, they were only different in heavy smokers and after short-term exposure. The results obtained suggest that 2,5-dimethylfuran is a specific breath biomarker of smoking status independently of the smoking habits (e.g., short- and long-term exposure, light and heavy consumption), and so this compound might be useful as a biomarker of smoking exposure.     

Capillary electrophoretic determination of inorganic anions in the drainage and surface water samples.

Capillary electrophoresis was used for separation and quantitation of several inorganic anions in the drainage and surface water samples from the region with extensive use of fertilisers. Baseline separation of 13 small anions including nitrite and nitrate up to the concentrations of 100 mg/l was achieved in less than 5 min. The electrolyte consisted of 3 mM K2CrO4, 30 microM cetyltrimethylammonium bromide and 3 mM boric acid at pH 8. The method yielded precisions of 1.8-7.2% (RSD, n = 10) and detection limits from 4 micrograms/l (Cl-) up to 500 micrograms/l (citrate). The results of the CE method were compared to ion chromatography using water-acetonitrile (86:14) at pH 8.6 adjusted with NaOH as the mobile phase and consistent results were obtained.     

Determination of organic acids in urine by solid-phase microextraction and gas chromatography-ion trap tandem mass spectrometry previous 'in sample' derivatization with trimethyloxonium tetrafluoroborate

A method for the determination of the organic acids directly in the urine employing derivatization with trimethyloxonium tetrafluoroborate as a methylating agent and sequential extraction by head space and direct immersion/solid phase microextraction is reported. Furoic acid, hippuric acid, methylhippuric acid, mandelic acid, phenylglyoxylic acid and trans, trans muconic acid contained in urine and proposed by the American Conference of Governmental Industrial Hygienists as biological exposure indices were determined after a fast and economically convenient preparation step and sensitive gas chromatography-ion trap-mass spectrometry/tandem mass spectrometry analysis. Urine is rather a complex sample and hence the acquisition method required specific GC-MS instrumentation capable of supporting the changeover, fully automated during a single chromatographic separation, from mass to tandem mass spectrometry and both chemical and electron ionization modes. The automation of the analytical method provides a number of advantages, including reduced analysis time for both routine analysis and method development, and greater reproducibility. The equilibrium and kinetics of this substances vs head space/direct immersion-solid phase microextraction were investigated and evaluated theoretically.     

Solid state polymerization of butadienes. Polymerization of long chain derivatives of sorbic and muconic acid

The polymerization of long chain derivatives of sorbic and muconic acid was studied in the solid state. Crystals of sorbic acid n-octadecylester (1), sorbic acid n-octadecylamide (2), and 6-n-octadecanoylamino sorbic acid (3) were found to rapidly polymerize upon UV- or-irradiation. A 1,4-trans-polymer was obtained in a high yield. Crystals of muconic acid di-n-octadecylester (4) and muconic acid di-n-octadecylamide (5) were completely photoinactive.Polymerization of3 was also investigated in monomolecular layers at the air-water interface and in Langmuir-blodgett type multilayers. The polymer formed upon UV- irradiation of mono- and multilayers was identified by infrared spectroscopy as the 1,4-trans-adduct.     

Liquid chromatography/mass spectrometry of pre-ionized Girard P derivatives for quantifying estrone and its metabolites in serum from postmenopausal women

An ultrasensitive stable isotope dilution liquid chromatography/selected reaction monitoring/mass spectrometry (LC/SRM/MS) assay has been developed for serum estrone, 16α‐hydroxyestrone, 4‐methoxyestrone, and 2‐ methoxyestrone. The enhanced sensitivity was obtained by the use of Girard P (GP) pre‐ionized derivatives coupled with microflow LC. The limit of detection for each estrogen using 0.5 mL of serum was 0.156 pg/mL and linear standard curves were obtained up to 20 pg/mL. Serum samples from 20 postmenopausal women (10 lifetime non‐smokers and 10 current smokers) were analyzed using this new assay. Mean serum concentrations of estrone and 2‐methoxyestrone were 14.06 pg/mL (±1.56 pg/mL) and 3.30 pg/mL (±1.00 pg/mL), respectively, for the 20 subjects enrolled in the study. The mean estrone concentration determined by our ultrasensitive and highly specific assay was significantly lower than that reported for the control groups in most previous breast cancer studies of postmenopausal women. In addition (and contrary to many reports) serum 16α‐hydroxyestrone was not detected in any of the subjects, and 4‐methoxyestrone was detected in only one of the subjects. Furthermore, there were no significant differences in the mean serum concentrations of estrone and 2‐methoxyestrone or the ratio of serum 2‐ methoxyestrone to estrone between the non‐smoking and smoking groups. Interestingly, the one subject with measurable serum 4‐methoxyestrone (2.3 pg/mL) had the lowest estrone and 2‐methoxyestrone concentrations. Using this assay it will now be possible to obtain definitive information on the levels of serum estrone, 4‐methoxyestrone, and 2‐methoxyestrone in studies of cancer risk using small serum volumes available from previous epidemiology studies. Copyright © 2011 John Wiley & Sons, Ltd.     

Application of a contactless conductometric detector for the simultaneous determination of small anions and cations by capillary electrophoresis with dual-opposite end injection

A contactless conductometric detection (CCD) system for capillary electrophoresis (CE) with a flexible detection cell was applied for the simultaneous determination of small anions and/or cations in rain, surface and drainage water samples. The applied frequency, the amplitude of the input signal, the electrolyte conductivity and electrode distance were found to be the most significant factors affecting the detection sensitivity. 2-(N-Morpholino)ethanesulfonic acid/histidine-based (MES/His) electrolytes were used for direct conductivity detection of anions and cations, while ammonium acetate was selected for indirect conductivity determination of alkylammonium salts. For the simultaneous separation procedure, involving dual-opposite end injection, an electrolyte consisting of 20 mM MES/His, 1.5 mM 18-crown-6 and 20 microM cetyltrimethylammonium bromide provided baseline separation of 13 anions and cations in less than 6 min. The detection limits achieved were 7-30 micrograms/l for direct conductometric detection of various common inorganic cations and anions, excluding F- (62 micrograms/l) and H2PO4- (250 micrograms/l), and 35-178 micrograms/l for indirect conductometric detection of alkyl ammonium cations. The developed electrophoretic method with conductometric detection was compared to ion chromatography.     

Ion‐pair‐based hollow‐fiber liquid‐phase microextraction combined with high‐performance liquid chromatography for the simultaneous determination of urinary benzene,toluene, and styrene metabolites

In the current study, a novel technique for extraction and determination of trans,trans‐muconic acid, hippuric acid, and mandelic acid was developed by means of ion‐pair‐based hollow fiber liquid‐phase microextraction in the three‐phase mode. Important factors affecting the extraction efficiency of the method were investigated and optimized. These metabolites were extracted from 10 mL of the source phase into a supported liquid membrane containing 1‐octanol and 10% w/v of Aliquat 336 as the ionic carrier followed by high‐performance liquid chromatography analysis. The organic phase immobilized in the pores of a hollow fiber was back‐extracted into 24 μL of a solution containing 3.0 mol/L sodium chloride placed inside the lumen of the fiber. A very high preconcentration of 212‐ to 440‐fold, limit of detection of 0.1–7 μg/L, and relative recovery of 87–95% were obtained under the optimized conditions of this method. The relative standard deviation values for within‐day and between‐day precisions were calculated at 2.9–8.5 and 4.3–11.2%, respectively. The method was successfully applied to urine samples from volunteers at different work environments. The results demonstrated that the method can be used as a sensitive and effective technique for the determination of the metabolites in urine.     

用反相高效液相色谱法分离和测定丁烯二酸的顺反异构体

建立了分离和测定丁烯二酸的２个异构体－顺丁烯二酸和反丁烯二酸的反相高效液相色谱法。以Ｓｈｉｍ－ｐａｃｋ ＣＬＣ－ＯＤＳ柱为分析柱,以甲醇－水（体积比５：２）,用磷酸调至ｐＨ３．０）为流动相,流速０．７ｍＬ／ｍｉｎ,检测波长为２２０ｎｍ,外标法定量。顺、反丁烯二酸的检出限分别为０．１０和０．０７５ｍｇ／Ｌ（Ｓ／Ｎ＝２）;相对标准偏差分别为０．４７％和０．５４％（ｎ＝３）。二者的线性范围均为１０～６０     

Determination of hexahydrophthalic anhydride in air using gas chromatography.

Two methods for the determination of hexahydrophthalic anhydride (HHPA) in air were developed. In a solid sorbent method, HHPA was sampled in Amberlite XAD-2 tubes, eluted in toluene and analysed by gas chromatography with flame ionization detection. The sampling rates were 0.2 and 1.0 l/min. At 15 micrograms/m3 (relative humidity less than 2%) and 27 micrograms/m3 (relative humidity 70%) no breakthrough was observed. However, at 160 micrograms/m3 (relative humidity less than 2%), 6% breakthrough was found. The sampling efficiency of the sampling rates 0.2 and 1.0 l/min did not differ. In a bubbler method, HHPA was sampled in bubblers filled with 0.1 M sodium hydroxide solution. The sodium salt of hexahydrophthalic acid was formed. No breakthrough was observed using a sampling rate of 1.0 l/min. The samples were stable during storage for eight weeks in a refrigerator. The HHP acid was esterified with methanol-boron trifluoride and analysed by gas chromatography-flame ionization detection. Apparatus for the generation of standard atmospheres of HHPA, in the range of 10-3000 micrograms/m3, was developed using the diffusion principle. For the solid sorbent method the precision (coefficient of variation) of the overall method was 2-7%, and for the bubbler method 3-19% (range 15-160 micrograms HHPA/m3; relative humidity = less than 2-70%). A comparison between the two methods was performed using the standard atmosphere. The concentrations found by the solid sorbent method were 86-98% of those found by the bubbler method (range 15-160 micrograms HHPA per m3; relative humidity = less than 2-70%). In work environment air, 93% was found using the solid sorbent method relative to the bubbler method at a mean concentration of 330 micrograms/m3 (coefficient of variation = 39%; range 200-540 micrograms/m3). For both methods, concentrations greater than 3 micrograms/m3 could be quantified at 60 min sampling with a sampling rate of 1.0 l/min.     

The determination of benzene in human blood as an indicator of environmental exposure to volatile aromatic compounds

Summary For the determination of ecologically caused benzene levels in human blood samples and for the evaluation of reference values for the general population a sensitive and reliable method was developed. The determination is performed by dynamic head space chromatography and FID-detection. The detection limit is 80 ng/l blood. The main problem is the avoidance of contamination during the preanalytical phase; precautions and recommendations are given. The mean benzene levels of nonsmokers are 176±62 ng/l, of smokers 211±85 ng/l; active smokers showed levels of 365±178 ng/l.     

Production of Diethyl Terephthalate from Biomass‐Derived Muconic Acid

We report a cascade synthetic route to directly obtain diethyl terephthalate, a replacement for terephthalic acid, from biomass‐derived muconic acid, ethanol, and ethylene. The process involves two steps: First, a substituted cyclohexene system is built through esterification and Diels–Alder reaction; then, a dehydrogenation reaction provides diethyl terephthalate. The key esterification reaction leads to improved solubility and modulates the electronic properties of muconic acid, thus promoting the Diels–Alder reaction with ethylene. With silicotungstic acid as the catalyst, nearly 100 % conversion of muconic acid was achieved, and the cycloadducts were formed with more than 99.0 % selectivity. The palladium‐catalyzed dehydrogenation reaction preferentially occurs under neutral or mildly basic conditions. The total yield of diethyl terephthalate reached 80.6 % based on the amount of muconic acid used in the two‐step synthetic process.     

Gas chromatographic-mass spectrometric determination of ethyl carbamate as the xanthylamide derivative in Italian aqua vitae (grappa) samples.

A selective reaction of ethyl carbamate (urethane) and methyl urethane (urethylane), as internal standard, with xanthydrol was effected to detect urethane after extraction from Italian aqua vitae (grappa) samples. The xanthylamides formed were determined by gas chromatography-mass spectrometry in the selected ion monitoring mode on an apolar DB 5 silica column. The linearity of the method was tested from 10 to 1000 micrograms/l, with a detection limit of 1 micrograms/l.     

尼古丁是脂肪酶的反竞争抑止剂的实验研究

希望明确尼古丁对脂肪酶活性是否有抑止作用,用于解释医学已有统计数据：吸烟的人体重普遍较轻,而戒烟后体重会有回升．用三油酸甘油酯为底物,在加入尼古丁前后,检测脂肪酶活性变化．结果表明：脂肪酶在人体外仍有活性,而且尼古丁是脂肪酶反竞争性抑止剂．在脂肪酶浓度为7mg／mL时,抑止程度达50％．     

Flow-injection chemiluminometric determination of some thioxanthene derivatives in pharmaceutical formulations and biological fluids using the [Ru(dipy)3(2+)]-Ce(IV) system.

A flow-injection (FI) methodology using tris(2,2'-dipyridyl)ruthenium(II), [Ru(dipy)3(2+)], chemiluminescence (CL) was developed for the rapid and sensitive determination of three thioxanthene derivatives, namely zuclopenthixol hydrochloride, flupentixol hydrochloride and thiothixene. The method is based on the CL reaction of the studied thioxanthenes with [Ru(dipy)3(2+)] and Ce(IV) in a sulfuric acid medium. Under the optimum conditions, calibration graphs were obtained over the concentration ranges 0.002-6 migrograms/ml for zuclopenthixol hydrochloride, 0.5-15 micrograms/ml for flupentixol hydrochloride and 0.05-7.5 micrograms/ml for thiothixene. The limits of detection (s/n = 3) were 4.2 x 10(-9) mol/l zuclopenthixol hydrochloride, 2 x 10(-8) mol/l flupentixol hydrochloride and 4.5 x 10(-8) mol/l thiothixene. The method was successfully applied to the determination of these compounds in dosage forms and biological fluids.     

Combining Metabolic Engineering and Electrocatalysis: Application to the Production of Polyamides from Sugar

Biorefineries aim to convert biomass into a spectrum of products ranging from biofuels to specialty chemicals. To achieve economically sustainable conversion, it is crucial to streamline the catalytic and downstream processing steps. In this work, a route that combines bio‐ and electrocatalysis to convert glucose into bio‐based unsaturated nylon‐6,6 is reported. An engineered strain of Saccharomyces cerevisiae was used as the initial biocatalyst for the conversion of glucose into muconic acid, with the highest reported muconic acid titer of 559.5 mg L^?1 in yeast. Without any separation, muconic acid was further electrocatalytically hydrogenated to 3‐hexenedioic acid in 94 % yield despite the presence of biogenic impurities. Bio‐based unsaturated nylon‐6,6 (unsaturated polyamide‐6,6) was finally obtained by polymerization of 3‐hexenedioic acid with hexamethylenediamine.     

Orientational control of guest molecules in an organic intercalation system by host polymer tacticity

Four kinds of stereoregular poly(muconic acid)s, which are synthesized by topochemical polymerization and subsequent solid-state hydrolysis, are used as the organic host materials for intercalation. We describe the reaction behavior and layered structure of intercalation compounds using stereoregular poly(muconic acid)s and n-alkylamines as host and guest, respectively. The packing structure of the guest alkylamines was determined by X-ray diffractions as well as IR and Raman spectroscopies. We have found that the orientation of the guest molecules is controlled by the host polymer tacticity, depending on the structure of the two-dimensional hydrogen-bonding network formed in the polymer sheets of the crystals.     

Analysis of oxyhalide disinfection by-products and other anions of interest in drinking water by ion chromatography.

The US Environmental Protection Agency is developing regulations for various drinking water disinfection by-products (DBPs). This effort involves developing analytical methods for the DBPs formed as a result of different disinfection treatments and collecting occurrence data for these species. Ion chromatography is one method being used to analyze drinking water samples for the following inorganic DBPs: chlorite, chlorate and bromate. These anions, however, are difficult to separate from common interfering anions of chloride, carbonate and nitrate. A method is therefore presented by which tetraborate/boric acid is used to separate these anions. Method detection limits of the order of 10 micrograms/l, using conductivity and UV detection were obtained. Stability studies of chlorite showing the effectiveness of ethylenediamine as a preservative and summary data for an occurrence of nitrite, nitrate and the DBP precursor bromide are presented.     

Comparison of cannabinoid concentrations in oral fluid and whole blood between occasional and regular cannabis smokers prior to and after smoking a cannabis joint

A cross-over controlled administration study of smoked cannabis was carried out on occasional and heavy smokers. The participants smoked a joint (11 % Δ9-tetrahydrocannabinol (THC)) or a matching placebo on two different occasions. Whole blood (WB) and oral fluid (OF) samples were collected before and up to 3.5 h after smoking the joints. Pharmacokinetic analyses were obtained from these data. Questionnaires assessing the subjective effects were administered to the subjects during each session before and after the smoking time period. THC, 11-hydroxy-THC (11-OH-THC) and 11-nor-9-carboxy-THC (THCCOOH) were analyzed in the blood by gas chromatography or liquid chromatography (LC)-tandem mass spectrometry (MS/MS). The determination of THC, THCCOOH, cannabinol (CBN), and Δ9-tetrahydrocannabinolic acid A (THC-A) was carried out on OF only using LC-MS/MS. In line with the widely accepted assumption that cannabis smoking results in a strong contamination of the oral cavity, we found that THC, and also THC-A, shows a sharp, high concentration peak just after smoking, with a rapid decrease in these levels within 3 h. No obvious differences were found between both groups concerning THC median maximum concentrations measured either in blood or in OF; these levels were equal to 1,338 and 1,041 μg/L in OF and to 82 and 94 μg/L in WB for occasional and heavy smokers, respectively. The initial WB THCCOOH concentration was much higher in regular smokers than in occasional users. Compared with the occasional smokers, the sensation of confusion felt by the regular smokers was much less while the feeling of intoxication remained almost unchanged.