Evaluation of Uncertainty in Determination of Ethyl Maltol in Vegetable Oil by Ultra-high Performance Liquid Chromatograph-Mass Spectrometer(UPLC-MS)

[Objectives]This study was conducted to establish an uncertainty evaluation method for the determination of ethyl maltol by ultra-high performance liquid chromatograph-mass spectrometer(UPLC-MS).[Methods]A mathematical model of uncertainty was established by analyzing the method for determining ethyl maltol using UPLC-MS.The sources of uncertainty were analyzed,and the components of uncertainty were calculated to evaluate the expanded uncertainty of the method.[Results]When the content of ethyl maltol in edible vegetable oil was 1657μg/kg,the expanded uncertainty was 22.4μg/kg(K=2,P=95%).[Conclusions]The uncertainty in this evaluation model mainly came from standard solution preparation,sample weighing,dilution of sample to constant volume,standard curve fitting,and repeated measurement.

Determination of volatile components in cut tobacco with gas chromatography-mass spectrometry and chemometric resolution

Chromatography-mass spectrometry(GC-MS)was used to analyze the volatile components of cut tobacco samples with the help of heuristic evolving latent projections(HELP).After extracting with simultaneous distillation and extraction method,the volatile components in cut tobacco were detected by GC-MS.Then the obtained original two-dimensional data were resolved into pure mass spectra and chromatograms.The qualitative analysis was performed by similarity searches in the national institute of standards and technology(NIST)mass database with the obtained pure mass spectrum of each component and the quantitative results were obtained by calculating the volume of total two-way response.The accuracy of qualitative and quantitative results were greatly improved by using the two-dimensional comprehensive information of chromatograms and mass spectra.107 of 141 separated constituents in the total ion chromatogram of the volatile components were identified and quantified,accounting for about 88.01% of the total content.The result proves that the developed method is powerful for the analysis of complex cut tobacco samples.

Automatic ^(40)Ar/^(39)Ar Dating Techniques Using Multicollector ARGUS VI Noble Gas Mass Spectrometer with Self-Made Peripheral Apparatus

A new fully automatic ^40Ar/^39Ar laboratory with a Thermo Scientific ARGUS VI mass spectrometer has been established in China University of Geosciences （Wuhan）. We designed and developed a mini efficient preparation system （80 mL）, a CO2 laser for heating samples, a crusher for extracting fluid inclusions within K-poor minerals and an air reservoir （31 L） and pipette （0.1 mL） system. The ARGUS VI mass spectrometer is operated by the Qtegra Noble Gas software, which can control the peripheral accessories, such as pneumatic valves, CO2 laser and crusher through a PeriCon （peripheral controller）. The experimental procedures of atmospheric argon ana- lyses, ^40Ar/^39Ar dating by laser stepwise heating and by progressive crushing in vacuo, can be fully automatically performed. The weighted mean of atmospheric ^40Ar/^36Ar ratios is 302.22＋0.03 （1σ, MSWD=0.74, n=200）, indicating that air reservoir and pipette system and the whole instrument sys- tem are very stable. This laboratory is a successful pioneer example in China to establish a new no- ble gas laboratory with self-made peripheral accessories expect for the mass spectrometer.

HS-SPME-GC-MS技术分析不同加工阶段的甲鱼腥味成分变化

为研究不同加工方式对甲鱼腥味成分的影响,采用HS-SPME-GC-MS技术对甲鱼预煮、卤制、烘烤不同加工阶段的腥味物质进行分析。结果表明,经NIST/Willey质谱数据库检索和文献对照,新鲜甲鱼共检出48种挥发成分,确定36种成分,包括烃类21种、醛类12种、醇类化合物5种、芳香类5种、羧酸类3种、酮类1种、酯类1种。其中以己醛的百分含量最多,为29.1%,有青草味;庚醛占10.69%,具有强烈的油脂氧化味;壬醛占12.58%,提供鱼腥味;占2.02%的对二甲苯有刺激味;占2.36%的1-辛烯-3-醇具有土腥味。认为己醛、壬醛、庚醛、1-辛烯-3-醇等共同形成了甲鱼的腥味。通过预煮、卤制、烘烤等加工工艺后,腥味成分已减少至只能检测出己醛和壬醛,且含量都不超过1%。表明经预煮、卤制、烘烤等加工可以有效控制甲鱼的腥味。

宰后不同冷藏时间对牛胃肌肉风味特征的影响

为了研究宰后牛胃肌肉挥发性风味物质的变化以及不同冷藏时间对牛胃肌肉风味的影响,以肉牛瘤胃和皱胃为试验材料,对不同冷藏时间点(0、3、5 d)的挥发性风味物质进行研究。采用气相色谱-质谱(gas chromatography-mass spectrometer,GC-MS)技术确定了关键挥发性风味物质的变化,并应用模糊综合评价法对瘤胃和皱胃的感官质量进行了评定。结果表明,宰后牛瘤胃检测到挥发性风味物质共78种,皱胃中共69种。其中,1-辛烯-3-醇、异戊醇、1-壬醇、乙酸、正己醛、异戊醛、庚醛、正辛醛、苯甲醛、3-羟基-2-丁酮、二甲基二硫、二甲基三硫、苯并噻唑、2-乙酰基噻唑和2-正戊基呋喃是瘤胃和皱胃中关键的呈香物质,己酸、壬醛、苯酚、吲哚是引起瘤胃和皱胃品质下降的关键风味物质。确定对瘤胃肌肉风味影响最大的时间为3 d,皱胃为0 d;模糊综合评价结果表明,瘤胃感官质量优劣顺序为3 d>0 d>5 d,皱胃感官质量优劣顺序为0 d>3 d>5 d。综合上述实验结果可知,宰后瘤胃肌肉冷藏3 d对风味的影响最大,皱胃冷藏0 d对风味的影响最大。

GC-O-MS分析赊店酒中的香气成分

为了探究浓香型白酒中的主要呈香物质,采取液液萃取法,用二氯甲烷作为萃取剂提取赊店酒中的挥发性香气化合物,采用气质联用技术(Gas Chromatography-Mass Spectrometer,GC-MS),进行条件优化并通过NIST11谱库检索,共鉴定出45种挥发性物质。用气相色谱-嗅觉测量法(gas chromatography-olfactometry,GC-O)分析共测出18种呈香物质,其中酯类12种,醇类1种,挥发性酸4种,芳香族1种。香气贡献较大的化合物是丁酸乙酯、戊酸乙酯、己酸乙酯、庚酸乙酯、辛酸乙酯、棕榈酸乙酯、乙酸和丁酸。

Method for rapid on-site identification of VOCs

Rapid on-site identification of volatile organic compounds （VOCs） in ambient air is an important first step in remediation efforts. This study describes modification of a commercially available, portable GC/MS system and development of an analysis protocol for rapid （〈 3 min） sampling and identification of VOCs typically found at contaminated sites at the low ppbv level.

Analysis of Fragrance Composition in Three Cultivars of Osmanthus fragrans Albus Group Flower by Gas Chromatography-Mass Spectrometry

With supercritical CO2 fluid extraction（SCFE）, essential oil was extracted from three cultivars of Xianning osmanthus. The fresh osmanthus flower was processed with a petroleum ether digestion method to produce the extractum. The yields of essential oil and extractum were 0.19 % and 0.13 % （m/m） respectively. The essential oil and fragrance composition and content extracted were analyzed with gas chromatography-mass spectrometer （GC-MS）. The result showed that essential oil contained 36.99%（area/total area） of ionone, ionol and 13.11% of linalool; ionone and ionol contained in extractum were as high as up to 33.33%, while linalool up to 21.92%. Whether essential oil or extractum contains only about 40% fat acid and other ester matters. None of environmental estrogen （phthalic ester） was found in fragrance ingredients. The result also showed that the quality of O. fragrans Albus group fragrance in Xianning is better than that produced in Hangzhou and Anhui districts.

Flavor Characteristics of Different Crops of Laver(Porphyra yezoensis)During One Harvest Cycle

The taste and odor analysis of the first,second,fourth and sixth crops of laver(Porphyra yezoensis)was obtained by electronic tongue,taste-related compound,electronic nose and gas chromatography-ion mobility spectrometer(GC-IMS).Through the detection of the electronic tongue,the pleasant tastes such as umami and richness are more intense in the early crops,which is consistent with the analysis results of free amino acids and flavored nucleotides.The electronic nose can clearly distinguish between different laver crops.GC-IMS separated and identified 36 volatile components from lavers,mainly including aldehydes,ketones,alcohols,esters,acids and aromatic substances.For the early harvested crops,nonanal,octanal,hexanal and benzaldehyde have a significant contribution to odor because of the high concentration and low threshold of these compounds.For the later harvested crops,the concentration of most ketones and some aldehydes increased.1-Octen-3-ol,malondialdehyde and heptanal constituted the main odor characteristics.

Genotoxic Effects of PAH Containing Sludge Extracts in Chinese Hamster Ovary Cell Cultures

Objective Many studies have been conducted in order to evaluate the genotoxicity of chemicals and waste materials, which utilized in vivo test protocols. The use of animals for routine toxicity testing is now questioned by a growing segment of society. Methods Keeping the above fact in mind, we have conducted in the present study the genotoxicity evaluation of oily sludge samples generated from a petroleum refinery and petrochemical industry and ETP sludge from petroleum refinery using DNA damage, chromosomal aberration, p53 protein induction and apoptosis in short term in vitro mammalian Chinese Hamster Ovary cell cultures. Results It is evident from the results that the oily sludge compounds derived from petroleum refinery and petrochemical industry could cause DNA damage, chromosomal aberration, p53 protein accumulation and apoptotic cell death on exposure to oily sludge extracts in the presence of metabolic activation system (S-9 mix), however, ETP sludge extract could not cause significant genotoxicity in comparison to oily sludge extract and negative control. Conclusion The effect may be attributed to polycyclic aromatic hydrocarbons present in the samples as evidenced from GC-MS.

黄酒中“焦糖香”特征香气物质葫芦巴内酯的检测及风味贡献研究

采用液液微萃取(liquid-liquid microextraction,LLME)结合气相色谱-质谱联用(gas chromatography-mass spectrometer,GC-MS)技术建立了黄酒中"焦糖香"特征香气物质葫芦巴内酯的快速分析方法。该方法检测限为0.66μg/L,定量限为1.02μg/L,不同类型黄酒中加标回收率在80%~120%之间,当日精密度和隔日精密度相对标准偏差均在10%以内,能够满足黄酒中葫芦巴内酯批量快速检测的需要。采用该方法测定了不同区域24款典型黄酒样品中葫芦巴内酯的含量,结果显示该物质在黄酒中普遍存在,含量在42.05~244.34μg/L之间。首次测定了黄酒基质中葫芦巴内酯的香气阈值(11μg/L),并基于香气活力值(odor activity value,OAV)研究了葫芦巴内酯在黄酒中的风味作用,结果显示所有测定样品中葫芦巴内酯含量均高于其香气阈值,表明该物质对黄酒整体香气具有重要影响。进一步比较分析发现葫芦巴内酯在浙江和上海地区黄酒中含量显著高于其他地区黄酒。

Protective Effect of Distillate and Redistillate of Cow’s Urine in Human Polymorphonuclear Leukocytes Challenged With Established Genotoxic Chemicals

Objective From the ancient period cow’urine has been used as a medicine. In Veda, cow’urine was compared to the nectar. In Susrut, several medicinal properties of cow’ urine have been mentioned and are known to cause weight loss, reversal of certain cardiac and kidney problems, indigestion, stomach ache, edema, etc. However, the literature and scripture did not mention the antigenotoxic properties of cow’urine. Methods In the present investigation, the antigenotoxic/ antioxidant properties of cow’ urine distillate and redistillate were studied in vitro. The antioxidant status and volatile fatty acid levels were determined. Actinomycin-D (0.1ol/L) and hydrogen peroxide (150 mol/L) were used for inducing DNA strand break with 0.1% DMSO as negative control. Dose for the antigenotoxic effect of cow’ urine was chosen from the dose response study carried out earlier. Results Both actinomycin-D and H2O2 caused statistically significant DNA unwinding of 80% & 75% respectively (P<0.001) as revealed by fluorimetric analysis of DNA unwinding (FADU), and the damage could be protected with the redistilled cow urine distillate (1, 50 & 100 ) in simultaneous treatment with genotoxic chemicals. Conclusion The redistillate of cowurine was found to possess total antioxidant status of around 2.6 mmol, contributed mainly by volatile fatty acids (1500 mg/L) as revealed by the GC-MS studies. These fatty acids and other antioxidants might cause the observed protective effects.

Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in surface sediment and bivalve from the Changjiang Estuary, China

Surface sediments and bivalves were collected from the Changjiang Estuary in December 2003 and November 2004, respectively. Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in these samples were measured with high-resolution chromatography (HRGC)/High Resolution Mass Spectrometer (HRMS). The concentrations of total PCDD/Fs and toxic equivalent (TEQ) were 169.83±119.63 and 0.81±0.36 pg/g dry weight (dw) in sediments, and 580.33±240.17 and 7.24±3.65 pg/g dw in bivalves. The homolog compositions of PCDD/Fs were similar among samples, the most abundant congener was octa-chlorinated dibenzo-p-dioxin (OCDD) and then octa-chlorinated dibenzofuran (OCDF) and 1,2,3,4,6,7,8-hepta-chlorinated dibenzo-p-dioxin (HpCDD). The herbicide pentachlorophenol (PCP) and sodium pentachlorophenol (Na-PCP) were proved the main source of PCDD/Fs in this area.

Study on the Aromatic Components of Green Plum Wine by HS-SPME-GC-MS

In order to better blend green plum wine and study aromatic components of green plum wine,a qualitative analysis on aromatic components of soaked base liquor,green plum soaked wine,green plum juice,and fermented wine of green plum juice by Head Space Solid-phase Microextraction( HS-SPME) and Gas Chromatograph Mass Spectrometer( GC-MS) was studied in this paper. Experiment results indicated that14,32,17,and 46 kinds of aromatic components were identified respectively from four samples. Different aromatic components determined the special flavor and taste of green plum wine. Unique aromatic components generated in soaking process include benzaldehyde,1-butanol,2-methyl-,S-(-),benzoic acid ethyl ester,and 5-( hydroxymethyl). Special aromatic components in green plum juice were furfural,phenylethyl alcohol,and benzyl alcohol. The aromatic components in fermented wine of green plum juice mainly included phenylethyl alcohol( 6. 941%,relative content of peak area,same below),1-butanol,3-methyl-( 6. 940%),octanoic acid,ethyl ester( 3. 734%),decanoic acid,ethyl ester( 2. 590%),hexanoic acid,ethyl ester( 2. 479%),ethyl 9-decenoate( 2. 080%),and 5-hydroxymethyl( 1. 756%). This study was expected to provide scientific basis and data reference for quality improvement of green plum wine.

Oxidation of Lingwu Coal Extraction Residue in Aqueous Sodium Hypochlorite under Mild Conditions

To investigate the structural features and provide an alternative method for high value-added utilization of coal, Lingwu coal was first extracted with organic solvent at room temperature. Then its extraction residue was oxidized in aqueous sodium hypochlorite(ASHC) under mild conditions. The effects of oxidation conditions, such as temperature, reaction time, the ratio of Lingwu coal extraction residue(LCER, g) to ASHC(m L) and p H value, on the product distributions and compositions were investigated. The results of gas chromatography/mass spectrometry(GC/MS) suggested that 53 kinds of methyl esterified products were detected in total, and benzene carboxylic acids were the main oxidation products, while chloro-substituted benzene carboxylic acids were the main by-products. Higher yield and fewer kinds of organic acids could be obtained at lower p H value, especially for the main objective product, benzene carboxylic acids.

Application of GC/EIMS in Combination with Semi-Empirical Calculations for Identification and Investigation of Some Volatile Components in Basil Essential Oil

Volatile components in the extracts of basil leaves (Ocimum basilicum L.) were identified by gas chromatography/mass spectrometry (GC/MS) with electron ionization (EI) mode. The major volatile components of basil under investigation are α-pinene, sabinene, β-pinene, d-limonene, eucalyptol, l-linalool and estragole. Electron ionization mass spectra of these compounds have been obtained and investigated. Furthermore, the semi-empirical MNDO [Modified Neglect of Diatomic Overlap] method was used to calculate the thermochemical data for the structural properties of these compounds.

Effect of Heat Input on Fume Generation and Joint Properties of Gas Metal Arc Welded Austenitic Stainless Steel

The effect of heat input on fume and their compositions during gas metal arc welding （GMAW） of AISI 316 stainless steel plates are investigated. Fume generation rate （FGR） and fume percentage were determined by ANSI/AWS F1.2 methods. Particle characterization was performed with SEM-XEDS and XRF analysis to reveal the particle morphology and chemical composition of the fume particles. The SEM analysis reveals the morphology of particles having three distinct shapes namely spherical, irregular, and agglomerated. Spherical particles were the most abundant type of individual particle. All the fume particle size falls in the range of less than 100 nm. Mechanical properties （strength, hardness and toughness） and microstructural analysis of the weld deposits were evaluated. It is found that heat input of 1.15 kJ/mm is beneficial to weld stainless steel by GMAW process due to lower level of welding fume emissions and superior mechanical properties of the joints.

MEASUREMENT OF CARBON MONOXIDE COLUMN CONTENT AND OTHER ATMOSPHERIC TRACE GASES FROM INFRARED SPECTRA

The measurement of column content of carbon monoxide,methane,and other atmospheric traces gases as well as aerosols has been conducted during the fall of 1992 and 1997,using an infrared spectrometer of moderate resolution in the cooperation of the Laboratory for Middle Atmosphere and Global Environment Observation(LAGEO),Institute of Atmospheric Physics, Chinese Academy of Sciences,with the Institute of Atmospheric Physics,Russian Academy of Sciences.The variation characteristics of atmospheric CO column content in Beijing area are presented.The analysis of the measurement shows that the CO column concentration of 0.10 mg cm^(-2)can be considered as the background over Beijing area.and the concentration as high as 0.75 mg cm^(-2)was observed under some unfavorable meteorological situations.

Novel Method for Indirect Determination of Iodine in Marine Products by Atomic Fluorescence Spectrometry

A method for the determination of iodine based upon compound H2HgI4, formed between I- and Hg1＋ in nitric acid and extracted in methyl isobutyl ketone（MIBK）, was developed via atomic fluorescence spectrometry（AFS）. After the compound is reduced with potassium borohydrid（KBH4）, the resultant mercury vapor was injected into the instrument and iodine was, therefore, indirectly determined. Experimental parameters such as the conditions of extraction reagents, aqueous phase acidity, elemental mercury diffusion temperature in a vial and other factors were investigated and optimized. Under the optimum experimental conditions, this method shows a detection limit of 0.038μg/L iodine and a linear relationship between 0.04-20 p.g/L. The method was applied to determining the iodine content in marine duck eggs, kelps, laver and Ganoderma lucidum spirulina, showing a relative standard deviation（RSD） of 2.15% and the recoveries in the range of 98.1%-102.5%.

Factors controlling the enrichment of natural gas in Kuche depression,Tarim Basin,NW China:Molecular geochemical evidence from sedimentary organic matter

Using molecular geochemical data from infrared spectrometer and pyrolysis gas chromatography-mass spectrometry, this paper investigates the petroleum generation characteristics of Jurassic coal measures from Kuche depression, Tarim Basin, NW China. The results showed that the Jurassic coaly rocks with medium maturity (R0%: 0.8-1.1) were enriched in gas-prone functionalities (-CH3) and low molecular weight pyrolysates (【nC21), indicating that the coaly rocks from Kuche depression were gas/condensate prone at the stages of middle to high maturation, and it was further supported by the oil/source correlation from well Yinan 2 in this region.