连续流动法测定卷烟主流烟气中氰化氢的影响因素及方法改进

为了使连续流动法更准确地测定卷烟主流烟气中的氰化氢(HCN),考察了甲醛、乙醛、丙酮、丙烯醛对连续流动法测定体系的影响,并考察了不同浓度的甲醛对测定体系的影响,以及稀释与不稀释卷烟烟气气相捕集液及粒相萃取液中HCN的稳定性.结果表明:①甲醛对连续流动法测定体系影响最大,乙醛、丙酮及丙烯醛影响较小,可以忽略;②当甲醛含量在5.80 μg/mL时,HCN测定值降低7.38％,当甲醛含量在11.49 μg/mL时,HCN测定值降低13.51％;③甲醛对样品的稳定性影响最大,乙醛、丙酮及丙烯醛影响较小,可以忽略;④不稀释卷烟主流烟气气相捕集液及粒相萃取液中的HCN稳定性差,稀释卷烟烟气气相捕集液及粒相萃取液的稳定性明显改善;⑤方法的回收率在100％ ～ 104％之间,相对标准偏差1.11％.该法与离子色谱法的HCN检测值的相对偏差＜5％.     

连续流动法测定卷烟主流烟气中的氨含量

在确定和选择了连续流动分析仪管路及运用石墨化炭黑固相萃取柱对样品进行净化处理的基础上,采用连续流动分析仪对不同卷烟主流烟气中的氨进行了测定.结果表明,连续流动分析仪分析得到的净化处理后样品中的氨含量是2.46～10.40μg/支,与离子色谱法分析的结果一致性较好.该方法日内重复性RSD＜3.5％,日间重复性RSD＜2.0％,加标回收率为91.3％～97.9％.说明本方法适应于快速准确测定卷烟主流烟气中的氨含量.     

国内外卷烟主流烟气中氨的分析比较

采用离子色谱法对国内外较有代表性的127种卷烟主流烟气中的氨进行了测定,方法的检测限为13.5 μg/ L , RSD 为4.9% , 空白加标回收率在89%～96%之间。结果表明:国内外卷烟主流烟气氨含量范围约为3.6～14.2 μg/ 支;国内和国外混合型卷烟氨含量的平均值基本相当,国内烤烟型卷烟主流烟气氨含量平均值低于国内外混合型卷烟。      

气相色谱-质谱联用法测定卷烟主流烟气中的丁香酚

建立了气相色谱-质谱联用测定卷烟主流烟气中丁香酚释放量的方法.研究了不同溶剂、捕集方式对目标物检测结果的影响,优选了色谱分析所用的内标物、特征离子以及程序升温等条件,并运用该方法对部分市售卷烟及单料卷烟样品进行了普查分析.结果表明:在优化条件下,丁香酚在0.05～5 mg/L的浓度范围内线性良好,相关系数(R2)为0.9993,低、中、高3个水平下的加标回收率在104.50％～110.52％之间,日内和日间相对标准偏差(RSD)分别为3.31％和5.87％,检出限为0.06μg/支,定量限为0.20 μg/支.该方法具有操作简便、灵敏、准确等特点,适合于卷烟主流烟气中的丁香酚释放量的测定.     

冷阱捕集-GC/MS法同时检测卷烟主流烟气中的环氧乙烷和环氧丙烷

为同时准确测定卷烟主流烟气中环氧乙烷和环氧丙烷,建立了冷阱捕集-气相色谱/质谱联用(GC/MS)方法。采用剑桥滤片捕集卷烟主流烟气粒相物,在低温冷阱条件下用甲苯捕集主流烟气气相物,利用GC/MS检测主流烟气气相物中环氧乙烷和环氧丙烷的释放量,对21种国内外不同焦油量卷烟主流烟气中的环氧乙烷和环氧丙烷进行了测定。结果表明:1该方法线性良好(R2≥0.999 7),环氧乙烷和环氧丙烷的检测限分别为0.03μg/支和6.8 ng/支,回收率在91.0%～101.5%之间,日内、日间精密度在2.4%～6.0%之间。221种卷烟样品主流烟气中环氧乙烷和环氧丙烷的释放量分别为1.4～17.8μg/支和158.8～1153.0 ng/支。该方法操作简单、结果准确可靠,适合于同时测定卷烟主流烟气中环氧乙烷和环氧丙烷的释放量。     

冷阱捕集-气相色谱-质谱法测定卷烟主流烟气中的呋喃

建立了测定卷烟主流烟气中呋喃的冷阱捕集-气相色谱-质谱(GC/MS)法。主流烟气中的呋喃用含有氘代内标(呋喃-d4)的冷甲醇吸收后在选择离子监测模式下进行GC/MS 分析;考察了11 个不同品牌卷烟在ISO 抽吸模式与加拿大深度抽吸模式下主流烟气呋喃的释放量。结果表明:方法的线性相关系数为0.999 7,检出限为0.028 μg/mL,加标回收率和相对标准偏差(RSD)分别为94.2%~98.5%和3.3%~4.6%。加拿大深度抽吸模式下卷烟主流烟气中呋喃的释放量为ISO 抽吸模式下的两倍以上,ISO抽吸模式下卷烟主流烟气呋喃释放量与实测焦油量显著线性相关。该方法适用于测定卷烟主流烟气中呋喃的释放量。      

国内外主要品牌卷烟主流烟气中气相自由基含量的对比分析

采用电子顺磁共振(EPR)自旋捕集法对国内外196种卷烟主流烟气中气相自由基含量进行了分析测定.结果表明:①卷烟主流烟气中气相自由基含量与焦油及烟碱检测值均无明显相关性,分析认为主要原因可能是卷烟配方中各单料烟的气相自由基含量差异较大;②在同等焦油盒标值下,国内烤烟型卷烟主流烟气中气相自由基平均含量远低于其它卷烟,国内外混合型卷烟主流烟气中气相自由基含量基本相近;③主流烟气中NO和气相自由基含量存在显著的线性相关性(R2=0.891).     

高效液相色谱法测定卷烟主流烟气中的苯并[a]芘

为了测定卷烟主流烟气中苯并[a]芘,考察了萃取条件、弗罗里硅土净化条件和色谱分离条件,建立了测定卷烟主流烟气中苯并[a]芘的高效液相色谱-荧光检测法,并采用该方法和国标法测定了肯塔基参考卷烟3R4F和国内参比烤烟以及国内50个牌号卷烟样品烟气中的苯并[a]芘。结果表明:①用环己烷超声萃取40 min效果较好;②用Agilent ZORBAX Eclipse PAH作色谱柱,乙腈和水为流动相,梯度洗脱,流速2.0 mL/min,30 min内苯并[a]芘色谱峰可以和杂质峰有效分开;③该法的平均回收率在98.13%～101.36%之间,RSD在1.29%～4.32%之间;④该方法的测定结果与国标法较为一致,二者不存在显著性差异。该方法适合卷烟主流烟气中苯并[a]芘的检测。     

抽吸方式对卷烟主流烟气氨释放量的影响

为考察抽吸方式对卷烟主流烟气中氨释放量的影响,采用ISO、Massachusetts和Health Canada 3种抽吸方案分别抽吸了15种国产卷烟,然后采用离子色谱法测定了这些卷烟主流烟气中氨的释放量.结果表明:①对于滤嘴打孔卷烟,与ISO抽吸方案相比,采用Massachusetts抽吸方案,混合型卷烟主流烟气中氨...     

超高效液相色谱快速测定卷烟主流烟气中7种挥发酚

为快速准确地测定卷烟烟气中的对-苯二酚、邻-苯二酚、间-苯二酚、苯酚、对-甲酚、邻-甲酚和间-甲酚,建立了同时测定卷烟主流烟气中7种挥发酚的超高效液相色谱( UPLC)方法.采用1％醋酸水溶液对捕集烟气粒相物的剑桥滤片超声萃取20 min,萃取液过滤后通过Acquity UPLC BEH C18色谱柱分离,以水相中含7.0×10-3 mol/Lβ-环糊精(β-CD)的流动相进行梯度洗脱,采用荧光检测器进行分析.该方法的相对标准偏差( RSD)为1.15％～5.79％,回收率为90％～102％,检测限为0.04 ～ 0.35 μg/支,分析时间9 min.该法适合批量卷烟主流烟气中7种挥发酚的快速分析.     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

Review of techniques to manufacture micro-hydrogel particles for the food industry and their applications

Microgels are ‘soft’ microscopic cross-linked polymeric particles that are being increasingly exploited in a variety of industries for rheology control, encapsulation and targeted delivery. They are valued because of the ability to tune their functionality to address specific applications in oil recovery, coatings, drug delivery, cosmetics, personal care and foods. Food microgels are typically biopolymer hydrogels in the form of microspheres, nanospheres (also called nanogels), spheroids and fibres. The utilisation of engineered microgels in foods has so far been limited, despite their great potential to address several needs in the food industry, including: satiety control, encapsulation of phytonutrients and prebiotics, texture control for healthier food formulations (e.g. reduced fat products), and targeting delivery to specific areas in the digestive tract. We review the scientific and patent literature on the utilisation and manufacturing methods for producing microgels with an emphasis on micro-hydrogels for food applications.     

12—A CRITIQUE OF SOME HYPOTHESES RELATING TO THE HETEROGENEITY OF THE HIGH-SULPHUR PROTEINS OF WOOL

Joubert and Burns prepared a large number of fractions from the high-sulphur proteins of wool and estimated their molecular weights and amino-acid compositions. Their data have been re-examined in order to look for statistically significant interrelations between amino acids and between the proportion of various amino acids and molecular weight. Statistical analysis of the data is also used to examine the credibility of some hypotheses concerning the mechanism of keratin biosynthesis and to provide further evidence for the existence of families of proteins within the high-sulphur fractions of wool.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of     

The Latest Data about Development of Chinese Printing Industry in 2013

In the 2014 China（Shanghai）International Printing Week,Director Wang Yanbin released the latest data about development of Chinese printing industry in 2013.According to statistics,in 2013,the total output value of Chinese printing industry exceeded 1trillion Yuan for the first time,reaching 1.03985 trillion Yuan.There were 105,000 printing enterprises in China,employees were 3.415 million.The total asset was 1.06247 trillion Yuan;     

The State Council Issued "Directory of Government Approved Investment Projects(2013 Edition)"

正On December 2nd,2013,the State Council issued the notification of"Directory of Government Approved Investment Projects(2013 Edition)"(hereafter referred to as"notification").It is pointed out in the"notification"that in order to further deepen reforms in investment systems and administrative examination and approval systems,simplify administrative procedures and delegate powers to lower levels,earnestly     

Top Ten News of China's Paper Industry 2013

On December 24th, 2013, the meeting on the selection of top 10 news of China＇s paper industry 2013 sponsored by 〈China Paper Newsletters〉 was held in Beijing. The yearly selection of the top l0 news, which began in 2000, has become a brand activity widely recognized in the industry thanks to the support from the authorities at all levels and public participation.     

National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the "13~(th) Five-Year Plan"

In Apri Commi major p Plan＂ （h 2014, the National Development and Reform ssion issued an announcement for selection of reliminary research projects for the ＂13th Five-Year ereafter referred to as ＂The Announcement＂）     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the latest scientific     

China textile machinery: taking off in progress

正Among the 1600 exhibitors who take apart in the ITMA ASIA+CITME2014 2/3 are Chinese manufactures.If the numerous figures failed to attract your attention,the increase of quality should draw your focus.To adopt the demand of developing textile machine market,domestic textile machinery enterprises now follow the slogan of"technology drives development"to enhance product competitiveness.Our domestic sellers will showcase product ranging from spinning,weaving,dyeing and printing,