Reversed phase ion-pair liquid chromatographic determination of nicotine in commercial tobacco products. 1. Moist snuff.   总被引：2，自引：0，他引：2  

L A Ciolino  H A McCauley  D B Fraser  D Y Barnett  T Y Yi  J A Turner 《Journal of agricultural and food chemistry》1999,47(9):3706-3712

The official methods for the determination of nicotine in commercial tobacco products (AOAC, CORESTA) are based on approaches that are not selective for nicotine (colorimetric measurement, steam distillation, perchloric acid titration), and the availability of published methods based on state-of-the-art chromatographic methods is limited. Reversed phase ion-pair liquid chromatography has been established as a viable alternative for the analysis of basic analytes. A reversed phase ion-pair liquid chromatographic method for the determination of nicotine in commercial tobacco products was developed and optimized in separate experiments (Ciolino, L. A.; Turner, J. A.; McCauley, H. A.; Smallwood, A. W.; Yi, T. Y. J. Chromatogr. 1999a, 852 (2), 451-463). An extensive within-laboratory performance study of the optimized method was subsequently conducted, and results are presented here for the determination of nicotine in commercial moist snuff. Results for the determination of nicotine in commercial cigarettes are presented in a subsequent paper.  相似文献   

Reversed phase ion-pair liquid chromatographic determination of nicotine in commercial tobacco products. 2. Cigarettes.   总被引：2，自引：0，他引：2  

L A Ciolino  D B Fraser  T Y Yi  J A Turner  D Y Barnett  H A McCauley 《Journal of agricultural and food chemistry》1999,47(9):3713-3717

A reversed phase ion-pair liquid chromatographic method for the determination of nicotine in commercial tobacco products was previously developed and optimized (Ciolino, L. A.; Turner, J. A.; McCauley, H. A.; Smallwood, A. W.; Yi, T. Y. J. Chromatogr. 1999a, 852 (2), 451-463) and provided reliable results for the determination of nicotine in commercial moist snuff (Ciolino, L. A.; McCauley, H. A.; Fraser, D. B.; Barnett, D. Y.; Yi, T. Y.; Turner, J. A. J. Agric. Food Chem. 1999b, 47, 3706-3712). The method uses an aqueous-based sample extraction and provides rapid separation of nicotine from the minor tobacco alkaloids and other commercial tobacco components. In the present work, the method is evaluated for the determination of nicotine in commercial cigarettes and compared to both an official AOAC method for total alkaloids in tobacco (AOAC, AOAC Official Methods of Analysis of AOAC International, 16th ed.; AOAC International: Gaithersburg, MD, 1995; pp 30-31), and a published GC method (Lyerly, L. A.; Greene, G. H. Beitr. Tabakforsch. 1976, 8 (6), 359-361). Good agreement was obtained between the ion-pair LC method and the GC method with relative differences in determined nicotine contents of 0.6 to 5% for a series of commercial and reference cigarettes.  相似文献   

A laser ablation method for the synthesis of crystalline semiconductor nanowires   总被引：5，自引：0，他引：5  

AM Morales  CM Lieber 《Science (New York, N.Y.)》1998,279(5348):208-211

A method combining laser ablation cluster formation and vapor-liquid-solid (VLS) growth was developed for the synthesis of semiconductor nanowires. In this process, laser ablation was used to prepare nanometer-diameter catalyst clusters that define the size of wires produced by VLS growth. This approach was used to prepare bulk quantities of uniform single-crystal silicon and germanium nanowires with diameters of 6 to 20 and 3 to 9 nanometers, respectively, and lengths ranging from 1 to 30 micrometers. Studies carried out with different conditions and catalyst materials confirmed the central details of the growth mechanism and suggest that well-established phase diagrams can be used to predict rationally catalyst materials and growth conditions for the preparation of nanowires.  相似文献   

Effects of dietary Camelina sativa products on digestible nutrient compositions for rainbow trout (Oncorhynchus mykiss)          下载免费PDF全文

J.M. Fraser  S.A. Collins  Z. Chen  S.M. Tibbetts  S.P. Lall  D.M. Anderson 《Aquaculture Nutrition》2017,23(5):973-982

Two trials were conducted to determine the effect of dietary inclusion of camelina (Camelina sativa) products on their digestible nutrient compositions in rainbow trout. In the first experiment, the following camelina products: full‐fat seed, oil, high‐oil residue meal (HORM), pre‐press solvent‐extracted meal (SECM) and toasted SECM were evaluated. In the second trial, the utilization of SECM, SECM soaked in water (WS), SECM treated with a multicarbohydrase, Superzyme?‐OM, SECM treated with Bio‐Phytase and SECM treated with Superzyme?‐OM and Bio‐Phytase (MIX) was determined. The experimental diets consisted of a basal diet and test ingredient with a ratio of 70:30, except for camelina oil where the ratio was 80:20. In Experiment 1, SECM had the highest level of digestible crude protein (352 g kg^?1), whereas the oil was the best source of digestible energy (8,063 kcal kg^?1) and digestible crude fat (908 g kg^?1). In Experiment 2, there were no significant differences in nutrient digestibility of SECM and HORM; however, WS and MIX had significantly more digestible dry matter and digestible crude fat than SECM and HORM. Camelina by‐products have the potential to replace fishery by‐products in rainbow trout feeds.  相似文献   

A crucian carp Carassius carassius (L.) in Loch Rannoch,Scotland: further evidence of the threat posed to unique fish communities by introduction of alien fish species     

D. Fraser  C. E. Adams 《水产资源保护:海洋与淡水生态系统》1997,7(4):323-326

1. This paper describes the discovery of a crucian carp Carassius carassius in Loch Rannoch, a species previously not recorded in this loch and only recorded in Scotland from five other lochs. 2. Establishment of fish species in a water body previously not containing that fish species can result in significant detrimental ecological changes within that water body, and once made, introductions are irreversible. 3. Given that such introductions are occurring with increased frequency it is recommended that (a) legislation is introduced to outlaw such translocations, and (b) parties with an interest in freshwater fish are educated to regard such translocations as unethical. ©1997 John Wiley & Sons, Ltd.  相似文献   

Test performance study for detection of Ralstonia solanacearum and Clavibacter sepedonicus in potato tubers with TaqMan PCR     

R. A. M. Vreeburg  M. Nas  B. De Paepe  T. Dreo  R. A. Gottsberger  E. Fornefeld  K. Fraser  S. Leonard  A. C. Le Roux  E. T. M. Meekes  C. Rivoal  L. Smits-Mastebroek  J. van Vaerenbergh 《EPPO Bulletin》2020,50(1):177-185

A test performance study (TPS) was organized in 2018 with ten official testing laboratories to evaluate the performance of different real-time PCR tests for the detection of Clavibacter sepedonicus and/or Ralstonia solanacearum in potato tubers. Participants were sent spiked potato extracts with low (0.8–1.2 × 10⁴ cfu mL^-1), medium (1.6–2.4 × 10⁵ cfu mL^-1) and high (1.6–2.4 × 10⁷ cfu mL^-1) bacterial loads, DNA extracts thereof and heel-end cores from symptomatic potato tubers. The four real-time PCR tests in this TPS for detection of C. sepedonicus were considered fit for purpose as principal screening methods. Two real-time PCRs in this TPS were considered fit for purpose as principal screening methods for detection of R. solanacearum. A third real-time PCR missed 23% of the DNA samples from low-level R. solanacearum spikes and is considered not fit for purpose as a principal screening method. Correct identification of spiked samples was lower when DNA extraction from the spiked samples was performed by the participating laboratories, highlighting the importance of appropriate DNA extraction protocols.  相似文献   

Revision and application of the LINKAGES model to simulate forest growth in central hardwood landscapes in response to climate change     

William D. Dijak  Brice B. Hanberry  Jacob S. Fraser  Hong S. He  Wen J. Wang  Frank R. ThompsonIII 《Landscape Ecology》2017,32(7):1365-1384

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