Reversed phase ion-pair liquid chromatographic determination of nicotine in commercial tobacco products. 2. Cigarettes.

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.     

Extraction of organic acids by ion-pair formation with tri-n-octylamine. Part 6. Determination of sorbic acid, benzoic acid, and saccharin in yogurt

The sorbate content of commercial yogurt samples is determined by reverse phase liquid chromatography following ion-pair extraction with tri-n-octylamine. Mean recoveries (70-88%), precision (1.1-3.3% RSD), and detection limit of the method are presented for sorbic acid, benzoic acid, and saccharin.     

Evaluation of Commercial Fe(III)‐Chelates Using Different Methods

Abstract

A collaborative assay among three laboratories was made in order to compare both the ion (CEN. EN 13368‐2:2001 E. Determination of chelating agents in fertilizers by ion chromatography. Part 2: EDDHA and EDDHMA, 2001a) and the ion‐pair (Lucena, J.J.; Barak, P.; Hernandez‐Apaolaza, L. Isocratic ion‐pair high‐performance liquid chromatographic method for the determination of various iron(III) chelates. J. Chromatogr. A 1996, 727, 253–264) high performance liquid chromatography (HPLC) methods as well as the soluble and complexed Fe (CEN. EN 13366:2001 E. Treatment with a cation exchange resin for the determination of the chelated micronutrient content and of the chelated fraction of micronutrients, 2001b) methods. Fifteen and ten samples of commercial fertilizers of Fe‐EDDHA, Fe‐EDDHMA, respectively were analysed by three laboratories using these methods. No significant differences were observed between the results obtained for the Fe‐EDDHA content using the Lucena et al. or CEN method. The first method makes it possible to distinguish between the meso and DL‐racemic diasteroisomers of Fe‐o, o‐EDDHA. For the Fe‐EDDHMA formulations, the CEN method gives higher values than the ion‐pair method, since in the first one Fe‐EDDH4,6MA coelutes with FeEDDHMA. Also the CEN method does not makes it possible to distinguish between Fe‐EDDHMA and Fe‐EDDH5MA products. The variability among laboratories was larger for the CEN method than for the Lucena et al. method.     

Chemical characterization of dissolvable tobacco products promoted to reduce harm

In 2009, the R. J. Reynolds Tobacco Co. released a line of dissolvable tobacco products that are marketed as an alternative to smoking in places where smoking is prohibited. These products are currently available in Indianapolis, IN, Columbus, OH, and Portland, OR. This paper describes the chemical characterization of four such products by gas chromatography-mass spectrometry (GC-MS). The dissolvable tobacco products were extracted and prepared by ultrasonic extraction using acetone, trimethylsilyl derivatization, and headspace solid phase microextraction (SPME). The following compounds were identified in the dissolvables using either ultrasonic extractions or trimethylsilyl derivatization: nicotine, ethyl citrate, palmitic acid, stearic acid, sorbitol, glycerol, and xylitol. The following compounds were identified in the dissolvables using headspace SPME: nicotine, ethyl citrate, cinnamaldehyde, coumarin, vanillin, and carvone. With the exception of nicotine, the compounds identified thus far in the dissolvables are either flavoring compounds or binders. The concentration of free nicotine in the dissolvables was determined from the Henderson-Hasselbalch equation and by measuring the pH and nicotine concentration by GC-MS. The results presented here are the first to reveal the complexity of dissolvable tobacco products and may be used to assess potential oral health effects.     

废弃烟叶燃料酒精发酵工艺探索（简报）

以资源丰富、含糖量高的云南废弃烟叶为原料,通过正交试验,考察不同菌种、不同水平营养添加液和不同原料处理方法对能源酒精发酵的影响。试验结果表明：菌种和营养添加液水平对酒精发酵影响不明显,采用去除烟碱的预处理方法和半固态发酵方法,能显著提高燃料酒精产率;在此基础上,该文提出了较优的工艺流程,产物除燃料酒精外,还包括有重要用途的烟碱。     

Inulin determination for food labeling

Inulin and oligofructose exhibit valuable nutritional and functional attributes, so they are used as supplements as soluble fiber or as macronutrient substitutes. As classic analytical methods for dietary fiber measurement are not effective, several specific methods have been proposed. These methods measure total fructans and are based on one or more enzymatic sample treatments and determination of released sugars. To determine inulin for labeling purposes, we developed an easy and rapid anion-exchange high-performance liquid chromatography (HPLC) method following water extraction of inulin. HPLC conditions included an Aminex HPX- 87C column (Bio-Rad), deionized water at 85 degrees C as the mobile phase and a refractive index detector. The tested foods included tailor-made food products containing known amounts of inulin and commercial products (cookies, milk, ice creams, cheese, and cereal bars). The average recovery was 97%, and the coefficient of variation ranged from 1.1 to 5% in the food matrixes. The obtained results showed that this method provides an easier, faster and cheaper alternative than previous techniques for determining inulin with enough accuracy and precision for routine labeling purposes by direct determination of inulin by HPLC with refractive index detection.     

Liquid chromatographic determination of melamine in beverages

A liquid chromatographic method is described for the determination of melamine in beverages. Melamine is separated by column chromatography using cation and anion exchange resin and determined by ion-pair liquid chromatography using an ODS column and a mixture of acetonitrile and 0.05M phosphate buffer (pH 3.0) containing 0.005M sodium 1-laurylsulfate (1 + 4, v/v) as mobile phase. Recoveries of melamine ranged between 90.3 +/- 7.8 and 102.1 +/- 5.6% at levels of 0.6 to 2.4 ppm in 4 kinds of beverages. The quantitation limit was 2.5 micrograms melamine in 50 mL beverage. The method was applied to the migration test of melamine from melamine-formaldehyde resin products to the beverages.     

Determination of total riboflavin in cooked sausages.

A simple and rapid method for determining riboflavin content in cooked sausages by ion-pair reversed-phase liquid chromatography has been set up. Samples were subjected to acid and enzymatic hydrolysis. Sample extracts were directly chromatographed, avoiding purification and concentration treatment. Final determination was performed by high-performance liquid chromatography with fluorescence detector (excitation, 227 nm; emission, 520 nm), on a 25 cm x 4 mm i.d. Spherisorb ODS-2 cartridge using a mixture of 5 mM heptanesulfonic acid adjusted to pH 2.7 with phosphoric acid and acetonitrile (75:25, v/v) as mobile phase. Precision of the method was 1.3% (within a day) and 2.6% (between days). The detection limit was 0.015 mg/100 g. The recovery was >95%.     

Analysis of grape Vitis vinifera L. DNA in must mixtures and experimental mixed wines using microsatellite markers

Because wine quality highly relies on the varietal composition of the must, the development of methods allowing the authentication of varieties in musts and wines would be of great value as a guarantee of quality. Microsatellite markers have already been applied to the authentication of grape juices (Faria, M. A.; Magalh?es, R.; Ferreira, M. A.; Meredith, C. P.; Ferreira Monteiro, F. J. Agric. Food Chem. 2000, 48, 1096-1100) and to the analysis of experimental wines (Siret, R.; Boursiquot, J. M.; Merle, M. H.; Cabanis, J. C.; This, P. J. Agric Food Chem. 2000, 48, 5035-5040). In the present paper, we accessed the usefulness of this technology for the analysis of must and wine mixtures. The detection limit of DNA mixtures was first estimated on DNA extracted from leaves: 4% of a foreign DNA can be detected. Analysis of must and wine mixtures (Chardonnay B/Clairette B and Syrah N/Grenache N) was performed on experimental fermentations. DNA was extracted along the fermentation process and analyzed using five microsatellite loci. The 70:30 (v/v) mixtures were successfully analyzed until the end of the fermentation. The applications of these results to commercial purposes are discussed.     

The form of nicotine in tobacco. Thermal transfer of nicotine and nicotine acid salts to nicotine in the gas phase

Thermal transfer to nicotine in the gas phase from neat nicotine, from various nicotine carboxylic acid salts, and from endogenous nicotine in Burley, Bright, and Oriental tobacco samples has been examined by thermogravimetric/differential thermal analysis/mass spectroscopy and evolved gas analysis. Under the conditions used in these studies, the peak transfer temperatures of these substances to nicotine in the gas phase are nicotine and nicotine acetate, both ca. 110-125 degrees C; nicotine malates, ca. 110-210 degrees C for nicotine to malic acid ratios of 1:0.56 and 1:1 and ca. 160-210 degrees C for a nicotine to malic acid ratio of 1:2; (S)-nicotine bis[(2R,3R)-hydrogen tartrate] dihydrate, ca. 195-210 degrees C; and tobacco samples, a range of ca. 160-220 degrees C. These results suggest that nicotine is mostly protonated in tobacco leaf. In all cases, the temperature of the transfer of nicotine to the gas phase was found to be many hundreds of degrees below the temperatures observed around the coal of a burning cigarette (smolder, ca. 500-775 degrees C; dynamic smoking, 600 to over 950 degrees C). Within the narrow zone of a puffing cigarette that encompasses an intermediate temperature range (125-250 degrees C), kinetic data suggest that these temperatures are not sufficient to volatilize significant amounts of nonprotonated nicotine, assuming any exists at all, during the short puff duration (2 s). It is concluded that nonprotonated nicotine and protonated nicotine (salts of nicotine with natural tobacco carboxylic acids) will transfer nicotine to smoke with comparable yields and efficiencies during the smoking process.     

Gas chromatographic determination of nicotine in environmental tobacco smoke: collaborative study

A gas chromatographic method for determination of vapor phase nicotine in environmental tobacco smoke (ETS) was collaboratively studied by 6 laboratories. Nicotine is desorbed from XAD-4 sample tubes with ethyl acetate containing triethylamine and determined by gas chromatography with nitrogen-selective detection. Each collaborator received blind duplicate samples at each of 6 nicotine concentrations. Three concentrations were generated by spiking XAD-4 tubes with known amounts of nicotine; the remaining 3 concentrations were ETS samples obtained in a carefully controlled environmental chamber containing sidestream and exhaled mainstream smoke from 1R4F Kentucky reference cigarettes. Repeatability and reproducibility relative standard deviations ranged from 4.4 to 11.1% and from 7.0 to 11.1%, respectively, for nicotine concentrations evaluated (up to 6 micrograms/cu m). The method has been adopted official first action.     

Reverse phase liquid chromatographic determination of bisacodyl in dosage forms

A method is described for the determination of bisacodyl in enteric-coated tablets and suppositories by liquid chromatography (LC). The method will also determine the hydrolysis degradation products monoacetylbisacodyl and desacetylbisacodyl. The sample is dissolved in 2-propanol, and the extract is diluted with the mobile phase and injected into a liquid chromatograph fitted with a mu Bondapak C18 column and an ultraviolet detector set at 254 nm. The column is eluted with methanol-acetonitrile-0.01M citric acid (25 + 25 + 50). The pooled mean recovery value for bisacodyl from commercial enteric-coated tablets and suppositories was 99.7% with a pooled coefficient of variation (CV) of 0.72%. For content uniformity assays, the CVs were 0.7 and 1.0% for groups of 10 individual commercial suppositories and tablets, respectively. Differences between assay values by the LC and USP XX methods were 0.2% of declared for enteric-coated tablets (n = 5) and 1.0% of declared for suppositories (n = 2). The LC method can determine as little as 0.015 microgram of the monoacetyl or desacetyl degradation product.     

Liquid chromatographic determination of ochratoxin A in coffee beans and coffee products

A liquid chromatographic method for the determination of ochratoxin A in coffee beans (green and roast), instant coffee, and coffee drink is described. The sample is subjected to extraction with methanol-1% aqueous sodium bicarbonate (1 + 1) and C18 cartridge cleanup. The extract is chromatographed on a Nucleosil 5C18 column with a mobile solvent of acetonitrile-water-0.2M phosphate buffer pH 7.5 (50 + 47 + 3) containing 3 mM cetyltrimethylammonium bromide as an ion-pair reagent. Ochratoxin A is detected with a fluorometer (excitation 365 nm, emission 450 nm). The sensitivity was increased 20-fold by using ion-pair resolution. The detection limits corresponded to 2 micrograms/kg for coffee beans, 5 micrograms/kg for instant coffee, and 0.2 microgram/kg for coffee drink. The recoveries from coffee products were generally better than 80.7% and the relative standard deviations were 3.43-5.93%. The peak coinciding with ochratoxin A can be confirmed by treatment using alcohol (methanol, ethanol, or n-propanol) and H2SO4.     

Effect of extraction procedure on measured sugar concentrations in onion (Allium cepa L.) bulbs

Bulb samples from a range of onion cultivars grown over three consecutive years were freeze-dried and the resulting powders extracted using three previously reported methods. The extracts were analyzed for fructose, glucose, and sucrose content using HPLC coupled with ELSD, and for fructans using MALDI-MS. The three methods gave differing results, indicating that the extraction procedure is crucial in the determination of the concentration and ratios of nonstructural carbohydrates in onion bulbs. O'Donoghue et al.'s method (O'Donoghue, E. M.; Somerfield, S. D.; Shaw, M.; Bendall, M.; Hedderly, D.; Eason, J.; Sims, I. J. Agric. Food Chem. 2004, 52, 5383-5390), which utilized a more polar solvent (62.5% (v/v) aqueous methanol) and also had the benefit of shorter extraction times and lower temperatures, was far superior to 80% (v/v) ethanol-based methods in extracting significantly greater amounts of fructose, glucose, and sucrose from all onion bulbs tested. Discrepancies between and within cultivars tested also demonstrated that the ratio of monosaccharides to sucrose was affected by extraction method, such that some caution should be given to interpreting some previous work on elucidating the nonstructural carbohydrate composition in onion.     

尼古丁降解菌L1的分离鉴定与降解特性分析

通过对分离于烟草叶片的154株具有降解尼古丁细菌菌株筛选，获得能高效降解尼古丁的L1菌株。通过形态观察，16S rDNA序列分析和生理生化测定将其鉴定为Bacillus simplex。菌落生长密度测定和高压液相色谱分析表明， L1菌株最适生长尼古丁浓度为1g/L，随着菌落密度增加，尼古丁降解效率逐渐升高，36 h最高降解率达到75.0%。而低尼古丁含量不利于L1菌株的生长，过高尼古丁含量对L1菌株的生长和降解效率具有反馈抑制作用。菌株L1降解尼古丁过程中无色素产生，说明其尼古丁代谢途径有别于节杆菌。     

Liquid chromatographic determination of six sympathomimetic drugs in dosage forms

A simple and rapid stability-indicating liquid chromatographic method is described for quantitative determination of 6 sympathomimetic drugs in various liquid and solid formulations. Analyses were carried out on a C18 reverse phase column using 0.01M 1-octanesulfonic acid, sodium salt in 0.2% acetic acid-methanol (70 + 30) as the mobile phase with photometric detection at 220 nm. Coefficients of variation for 5 consecutive injections of a mixed standards solution ranged from 0.62% for metaraminol to 1.40% for epinephrine. Standard recoveries ranged from 98.8% for metaraminol to 100.8% for epinephrine. The method was linear between 0.2 and 10 micrograms of drug injected and was used successfully to analyze 17 commercial products in a variety of dosage forms.     

Liquid chromatographic determination of pentaerythritol tetranitrate in pharmaceuticals: collaborative study

A liquid chromatographic (LC) method for the determination of pentaerythritol tetranitrate (PETN) in pharmaceutical formulations and the bulk drug triturate was evaluated in an interlaboratory study that included 12 participating laboratories. The procedure involves extraction of the active ingredient with mobile phase, followed by filtration of the extract and reverse-phase liquid chromatography using an octadecylsiliane bonded phase column and UV detection at 230 nm. The mobile phase composition is 35% water in acetonitrile (v/v). Three bulk drug samples (20, 20, and 35% PETN), 2 commercial tablet formulations (20 and 80 mg PETN/tablet), and 1 commercial capsule formulation (45 mg PETN/capsule) were analyzed in duplicate by the proposed method. Repeatability (sr, RSDr) and reproducibility (SR, RSDR) based on peak height measurement for these samples ranged from 0.0066 to 0.1806 (0.53-3.36%) and 0.0165 to 0.2075 (0.76-3.86%), respectively. Results for peak area measurements ranged from 0.0145 to 0.2011 (0.93-3.74%) and 0.0231 to 0.2091 (1.28-3.89%), respectively. The method has been approved interim official first action by AOAC.     

Fast analysis of nicotine in tobacco using double-shot pyrolysis--gas chromatography--mass spectrometry

A simple, rapid, and sensitive assay of nicotine in tobacco has been developed using pyrolysis-gas chromatography-mass spectrometry (DSP-GC-MS). The optimum pyrolyzer (desorption) conditions, using Korean tobacco grade B1O (0.4 mg) and n-heptadecane as an internal standard, were found to be heating from 50 to 300 degrees C at a rate of 60 degrees C/min. Replicate determinations (n = 5), on the same tobacco and using n-heptadecane as the internal standard, resulted in a nicotine content of 1.96%, with a relative standard deviation (RSD) of 1.9%. This result was in good agreement with those from established methods: the Cai ether extraction method, a chloroform extraction method, and the CORESTA recommended method. However, the DSP method requires less than half the time of the solvent extraction methods, requires less sample, is almost solvent-free, and is less labor-intensive. The DSP method was used to determine the nicotine content of eight flue-cured tobaccos from Brazil, China, Korea, and the United States, which were found to have contents ranging from 1.21 to 2.19%.     

Determination of vitamin D3 in liquid multivitamin preparation, using reverse phase, solid phase extraction liquid chromatography

A method is described for the determination of vitamin D3 in a liquid multivitamin preparation by liquid chromatography. Samples are purified on a disposable reverse phase extraction (SPE) column with a mobile phase of methanol-2-propanol (97 + 3) and are analyzed on a Zorbax ODS (5 micron) column with an acetonitrile-2-propanol-water (90 + 8 + 2) solvent system. Vitamin D3 is completely resolved from other interfering compounds within approximately 21 min and is detected with a UV detector at 254 nm. A mean of 98.5% of theory with a coefficient of variation of 3.8% was found for determination of vitamin D3 in a commercial preparation.