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.     

Evaluation of the solubility and emulsifying property of soybean proglycinin and rapeseed procruciferin in relation to structure modified by protein engineering

The presence or absence of a highly negatively charged extension region in beta-conglycinin (J. Agric. Food Chem. 1999, 47, 5278) and the length of a highly negatively charged variable region IV in glycinin (J. Agric. Food Chem. 2004, 52, 8197) are important determinants of solubility and emulsifying property. To examine the effects of the variable region IV from proglycinin A1aB1b and A3B4 and of the extension region from beta-conglycinin alpha' (alpha'ext) on solubility and emulsifying properties in detail, several mutants of proglycinin, procruciferin, and beta-conglycinin were designed and prepared in Escherichia coli. Nine out of 10 mutants were expressed at high levels in E. coli and shown to be homotrimer similar to the wild types as assessed by gel filtration. The position of the introduced negatively charged region as well as the amino acid composition were demonstrated to affect solubility at mu = 0.08. All of the proglycinin, procruciferin, and beta-conglycinin mutants with the alpha'ext in the C-terminus, especially the proglycinin mutant, exhibited excellent emulsifying ability and emulsion stability. These indicate that improvement of emulsifying properties by insertion of the alpha'ext in the C-terminus may be generally applicable to seed globulins.     

Authenticity of the traditional cypriot spirit "zivania" on the basis of 1h NMR spectroscopy diagnostic parameters and statistical analysis

A previous publication (Kokkinofta et al. J. Agric. Food Chem. 2003, 51, 6233-6239) discussed the use of inductively coupled plasma spectroscopy to differentiate between the traditional Cypriot alcoholic beverage zivania and other spirits similar in alcoholic content collected from different countries. In the present paper (1)H NMR spectroscopy is applied to confirm the previous conclusions and to obtain additional physical-chemical characteristics that may be used to differentiate zivania from other similar beverages. NMR spectroscopy gave a satisfactory degree of prediction and classification between zivanias and other distillings. The validity of quantification of the method was tested using comparative GC data. It appears that chemical analysis can be very helpful for identifying the unique geological and climatic conditions existing in the island of Cyprus that lead to an authentic product.     

Aroma comparisons of traditional and mild yogurts: headspace gas chromatography quantification of volatiles and origin of alpha-diketones

A quick headspace GC method for quantification of volatiles was developed, involving only minor sample preparation. Yogurt flavor compounds could be quantified in the micrograms per kilogram to milligrams per kilogram range without any difficulty, despite the complex matrix. Volatiles of traditional acidic and mild, less acidic yogurts were compared, and important differences were found for acetaldehyde, 2,3-butanedione, and 2,3-pentanedione. Concentrations of 2,3-butanedione and 2,3-pentanedione increased 2-3-fold in mild, less acidic yogurts compared to traditional acidic ones. This is due to accumulation of the precursors of the diketones, 2-acetolactate and 2-acetohydroxybutyrate, during fermentation in mild, less acidic yogurt. These precursors are subsequently converted to the corresponding diketones during storage. On the contrary, acetaldehyde formation was reduced in the mild yogurt, due to growth differences between the lactic acid bacteria used for fermentation of the milk. The quantitative results presented in this study validate previous GC sniffing conclusions (Ott et al. J. Agric. Food Chem. 1997, 45, 850-858), showing that yogurt aroma is the superposition of impact flavor compounds generated by fermentation on milk compounds.     

Ultrastructure of individual and compound starch granules in isolation preparation from a high-quality, low-amylose rice, ilpumbyeo, and its mutant, G2, a high-dietary fiber, high-amylose rice

The ultrastructures of isolated starch granules from Ilpumbyeo (IP), a low-amylose japonica rice, and its mutant, Goami2 (G2), a high-amylose rice, which have extreme contrasts in physicochemical properties, cooking qualities (Kang, H. J.; Hwang, I. K.; Kim, K. S.; Choi, H. C. Comparative structure and physicochemical properties of Ilpumbyeo, a high-quality japonica rice, and its mutant, Suweon 464. J. Agric. Food Chem. 2003, 51, 6598-6603. Kim, K. S.; Kang, H. J.; Hwang, I. K.; Hwang, H. G.; Kim, T. Y.; Choi, H. C. Comparative ultrastructure of Ilpumbyeo, a high-quality japonica rice, and its mutant, Suweon 464: Scanning and transmission electron microscopy studies. J. Agric. Food Chem. 2004, 52, 3876-3883), and susceptibility to amylolytic enzymes (Kim, K. S.; Kang, H. J.; Hwang, I. K.; Hwang, H. G.; Kim, T. Y.; Choi, H. C. Fibrillar microfilaments associated with a high-amylose rice, Goami2, a mutant of Ilpumbyeo, a high-quality japonica rice. J. Agric. Food Chem. 2005, 53, 2600-2608), were compared. In isolated preparation, IP consisted entirely of well-separated individual starch granules (ISG), whereas G2 consisted of two populations, the large voluminous bodies and the smaller forms, the ISGs. High-voltage electron microscopy revealed that each of the voluminous bodies consisted of tightly packed smaller subunits, the ISGs, indicating that they represent the compound starch granules (CSGs) of G2. This suggests that the structural as well as functional unit of G2 involved in food processing is, unlike IP and other ordinary rices, not ISG but is primarily CSG. ISGs located at the periphery of CSGs were fused to each other with adjacent ones forming a thick band or wall encircling the entire circumference. The periphery of ISGs separated from CSGs of G2 consisted of thin radially oriented filaments arranged side by side along the entire granule surface, whereas no such filaments occurred in ISG of IP. It appears that the thick band and the peripheral filaments surrounding CSGs and ISGs, respectively, function as a structural barrier that limits the entrance of water into the granules and subsequent absorption, causing the low swelling power, incomplete gelatinization, and finally poor quality of cooked rice in G2.     

Detection of pork and lard as adulterants in processed meat: liquid chromatographic analysis of derivatized triglycerides

A new method is described for detection of pork and lard as adulterants in processed beef and mutton mixtures. The unsaturated triglycerides in the fat are ozonized and then derivatized. The mixture of derivatized and saturated triglycerides is analyzed by liquid chromatography using a reverse-phase column and a UV detector. Pork fat has larger amounts of triglyceride containing saturated fatty acid at the C-2 position than does the fat of other meat. The ratio of triglyceride containing saturated fatty acid vs triglyceride containing unsaturated fatty acid at the same (C-2) position (SSU/SUS) in a sample is compared with those of pure meats. The presence of pork in the sample causes the ratio to increase compared with ratios for pure beef or mutton. The increase in the SSU/SUS ratio is significant for the addition of 1% pork in beef. In the case of mutton, the addition of 3% pork causes a noticeable change. The method is reliable and is also applicable to samples containing only fat. Processing (heating or cooking) does not affect the ratios.     

Antioxidative effect of quercetin and its equimolar mixtures with phenyltin compounds on liposome membranes

Our earlier studies have shown that the compounds diphenyltin dichloride (DPhT) and triphenyltin chloride (TPhT) in the presence of UVC radiation enhanced the degree of phosphatidylcholine liposome membrane oxidation (J. Agric. Food Chem. 2005, 53, 76-83). The prooxidative behavior of the compounds has now been confirmed with the electron paramagnetic resonance method, which proved the possibility that the studied compounds can exist in free radical forms. The present work investigates the possibility of the protective action of quercetin on phosphatidylcholine liposome membranes exposed to the prooxidative action of DPhT and TPhT induced by UV radiation (lambda = 253.7 nm). The concentrations of quercetin and its equimolar mixtures with DPhT and TPhT were determined (and compared with well-known antioxidants as standards-trolox and butylated hydroxytoluene, also in the presence of phenyltins) as those that induce 50% inhibition in oxidation of liposomes radiated with UV. They are 5.1 +/- 0.10, 2.9 +/- 0.12, and 1.9 +/- 0.08 microM (differences between the values are statistically significant), constituting the following sequence of antioxidative activity: quercetin:TPhT > quercetin:DPhT > quercetin. This relation is confirmed by the results on the antiradical ability of quercetin and its mixtures with DPhT and TPhT toward the free radical 1,1-diphenyl-2-pricrylhydrazil. Similar sequences obtained in both studies suggest a possible mechanism of the antiradical action of the mixtures as free radical scavengers. We suggested that (i) quercetin's ability, documented by spectrophotometric, infrared attenuated total reflectance spectroscopy, (1)H NMR, and molecular modeling methods, to form complexes with phenyltins indicates a possible way of protection against the peroxidation caused by the free radical forms of phenyltins and (ii) the differentiation in the action of the quercetin/TPhT and quercetin/DPhT associates (statisticaly significant) may result from a different localization in the liposome membrane, which is indicated by the results of the fluorimetric studies.     

Solid phase microextraction/gas chromatography of Salmonella-infected beef

Eight strains of Salmonellae were incubated in TSB culture medium at 37 degrees C for 24 h. Volatile compounds derived from the bacteria were collected using solid-phase microextraction fibers and then applied to gas chromatography (GC). Similarity analysis of the GC patterns thus obtained could separate these strains on principal component similarity (PCS) scattergrams. Five major food-related pathogenic bacteria and 10 other bacteria (including one Salmonella strain) were also classified by growing in the same medium. It is then proposed to utilize this approach to improve the GC/PCS method of Nakai et al. [Nakai, S.; Wang, Z. H.; Dou, J.; Nakamura, S.; Ogawa, M.; Nakai, E.; Vangerstoep, J. J. Agric. Food Chem. 1999, 47, 576-583] that has been developed for screening safe foods by detecting bacteria contaminated foods. Inoculating food samples pre-enriched through preliminary incubation into a culture medium and then subjecting to the GC/PCS method after secondary incubation enhances the detectability of pathogenic bacteria.     

Absorption of black currant anthocyanins by monolayers of human intestinal epithelial Caco-2 cells mounted in ussing type chambers

Anthocyanins (ACNs) have been reported to have multiple biological properties imparting benefits to human health. Their role in human nutrition, however, needs to be related to biokinetic data, such as bioavailability. The purpose of the present study was to focus on the potential absorption of black currant ( Ribes nigrum L.) ACNs. Caco-2 monolayers were used as an in vitro model of the absorptive intestinal epithelium. For absorption studies, Caco-2 cells grown on permeable filters were mounted into Ussing type chambers. The monolayer integrity was monitored by measuring the transepithelial electrical resistance (TEER). Luminal to serosal transport of ACNs was examined by comparing ACN disappearance from the luminal solution of Ussing chambers not containing any inserts (control chambers) with that of Ussing chambers containing inserts. ACNs (C total ACN approximately 180 microM) were not detected in any serosal solution. However, it was shown that ACNs disappeared from the luminal side, not due to ACN degradation processes but rather--at least in part--due to physiological actions of the cells. The luminal net disappearance of ACNs was calculated (max(t20 min) approximately 11% for total ACNs) and labeled as "absorption efficiency". This apical transport might occur to a much larger extent than the further translocation across the basolateral membrane. Thus, cell metabolism and translocation across the basolateral membrane may be the key determinants of ACN absorption and bioavailability.     

Development and evaluation of an immunological approach for the identification of novel acetyl coenzyme-A carboxylase inhibitors: assay optimization and pilot screen results

Cyclohexanediones, aryloxyphenoxypropionates, indolizidinediones, and triazinediones are four known structural classes of herbicides that inhibit acetyl coenzyme-A carboxylase (ACCase; EC 6.4.1.2). An immunological study to determine the potential of ACCase inhibitor-specific monoclonal antibodies as screening tools to identify novel lead chemistry was undertaken. Using two cyclohexanedione-specific monoclonal antibodies (mAb A and mAb B; Webb, S. R.; Hall, J. C. J. Agric. Food Chem. 2000, 48, 1210-1218) and three different cyclohexanedione hapten coating conjugates, competitive indirect enzyme-linked immunosorbent assays (ciELISA) were developed. Cross-reactivity of the monoclonal antibodies with four structural classes of ACCase inhibitors revealed that the ciELISA using mAb A and a modified cyclohexanedione hapten coating conjugate detected analogues from all four known classes of ACCase inhibitors. A pilot screen using this ciELISA format identified two novel ACCase inhibitors, demonstrating the potential for antibodies as rapid and cost-effective screening tools for identifying novel lead chemistry in pesticide discovery programs.     

Fate of anthocyanins and antioxidant capacity in contents of the gastrointestinal tract of weanling pigs following black raspberry consumption

Many fruits are rich in anthocyanins (ACNs). ACNs have high antioxidant capacity, but because of their apparent low bioavailability, their possible roles in health promotion in vivo are still in question. The objectives of these studies were to determine the fate of ACNs within the gastrointestinal (GI) tract and the effect on the bioavailability and subsequent metabolism of ACNs. Five weanling pigs were fed freeze-dried black raspberry (Rubus occidentalis L.) powder by oral administration, which provided 1146.1 +/- 44.6 micromol TE of oxygen radical absorbance capacity with fluorescein as a fluorescent probe (ORAC(FL)) per kg and 50.5 +/- 3.7 mg per kg total ACNs. After 4 h, the pigs were sacrificed and the contents of five GI segments (duodenum, jejunum, ileum, cecum, and colon) were collected and analyzed for their total antioxidant capacity (TAC, measured as ORAC(FL)) and ACNs. The recoveries of TAC and total ACNs were 46.5 +/- 3.5 and 41.7 +/- 4.9%, respectively. Both total ACNs and TAC were recovered primarily in the ileum, cecum, and colon at 4 h after a meal. Cyanidin aglycone with different sugar moieties showed significant differences in their recovery within the GI tract with sambubiose > sambubiose-rhamnose = rutinose > glucose. Recovery of ACNs within the GI tract was positively and linearly associated with urinary ACN recovery, which suggests that stability within the GI tract and not decreased absorption accounts for the increased recovery. The environment of different segments of the GI tract may determine the stability of individual ACNs. Complex ACNs containing di- or triglycosides disappeared more slowly in the GI tract than simple ACNs such as a monoglycoside. TAC and total ACNs remained high 4 h after feeding, which indicates that ACNs provide significant antioxidant protection in the environment of the gut epithelium.     

Interactions between methyl ketones and beta-lactoglobulin: sensory analysis, headspace analysis, and mathematical modeling

Interaction of flavor compounds with proteins is known to have an influence on the release of flavor from food. Hydrophobic interactions were found between beta-lactoglobulin and methyl ketones; the affinity constant increases by increasing the hydrophobic chain. Addition of beta-lactoglobulin (0.5 and 1%) to aroma solutions (12.5, 50, and 100 microL L(-)(1)) of three methyl ketones induces a significant decrease in odor intensity. The chosen methyl ketones were 2-heptanone (K(b) = 330), 2-octanone (K(b) = 950), and 2-nonanone (K(b) = 2440). The release of these flavor compounds (50 microL L(-)(1)) was studied by static headspace in water solution (50 mM NaCl, pH 3) with different concentrations of beta-lactoglobulin (0, 0.5, 1, 2, 3, and 4%). Increasing the concentration of protein increases the retention of volatiles, and this effect is greatest for 2-nonanone, the compound with the highest affinity constant, and lowest for 2-heptanone. A mathematical model previously developed to describe flavor release from aqueous solutions containing flavor-binding polymers (Harrison, M.; Hills, B. P. J. Agric. Food Chem. 1997, 45, 1883-1890) was used to interpret the data. The model assumes that the polymer-flavor interaction is reversible and the rate-limiting step for release is the transfer of volatiles across the macroscopic gas-liquid interface. This model was used to predict the equilibrium partitioning properties and the rate of release of the three methyl ketones. Increasing the affinity constant leads to decreased release rates and a lower final headspace aroma concentration.     

Distribution of aflatoxin in pistachios. 7. Sequential sampling

Sequential sampling for aflatoxin testing in pistachios is evaluated using the aflatoxin distribution and Monte Carlo results previously obtained (J. Agric. Food Chem. 1999, 47, 3771-3775). The sequential protocol is modeled on the current EU test protocol by applying a three-step sampling, using 10, 20, and 30 kg sample averages. An acceptance level of 15 ng/g of total aflatoxin, under consideration for U.S. standards, is applied. Optimization leads to indifference regions of 2-30 ng/g for the first two steps. The resulting OC curve approximates that for a single 50 kg sample. The sequential protocol is applied to the results for a set of 1293 lots of the 1998 crop year, each tested with a single 10 kg sample. Ninety-five percent of the lots would have been accepted on the basis of the single test and 1.5% would have been rejected, whereas 3.5% of the lots would have required retesting.     

Pressure and temperature stability of 5-methyltetrahydrofolic acid: a kinetic study

Detailed kinetic studies of [6S] and [6RS] 5-methyltetrahydrofolic acid (5-CH3-H4folate) degradation during thermal (from 60 to 90 degrees C) and high pressure/thermal (from 30 to 45 degrees C; from 200 to 700 MPa) treatments were carried out. The results confirmed that the temperature and pressure induced degradation kinetics of [6S] 5-CH3-H4folate were identical (within 95% confidence interval) with those of [6RS] 5-CH3-H4folate. Under equal processing conditions, the estimated degradation rate constants (k), activation energy (E(a)), and activation volume (V(a)) values of [6S] and [6RS] 5-CH3-H4folate were the same (95% confidence interval). The modified thermodynamic model proposed by Nguyen and co-workers (J. Agric. Food Chem. 2003, 51, 3352-3357) to describe the pressure and temperature dependence of the rate constant for folate degradation was reevaluated.     

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.     

Bipolar membrane electroacidification to produce bovine milk casein isolate

Bipolar membrane electroacidification (BMEA) has been developed previously (Bazinet et al., Report for the Canadian Electricity Association 9326 U 987, 1996; Bazinet et al., J. Agric. Food Chem. 1997, 45, 2419-2425, 3788-3794) and has been used for isoelectric precipitation of soybean proteins. The purpose of this study was to validate the feasibility of BMEA for the precipitation of milk casein and to investigate the effect of flow rate. High-purity isolates containing 1.23 and 2.00% ash and 85.4 and 91.6% total protein were obtained with flow rates of 0.2 and 1.2 gal/min. The molecular composition profiles of the isolates obtained by HPLC showed that only caseins were precipitated. However, except for protein precipitation curves, the flow rate did not influence the final composition and purity of the isolates. These results showed that BMEA is a new alternative process for the production of high-purity bovine milk casein isolate.     

Comparison of two dietary folate intake instruments and their validation by RBC folate

An optimal folate nutritional status is important in minimizing developmental and degenerative disease. Therefore, constant monitoring of folate intake and of biomarkers of folate nutritional status is essential. The objective of this research was to compare two folate intake instruments and validate each one against RBC folate measured by a high-throughput liquid chromatography tandem mass spectrometry (HT LC-MS/MS) method described in the companion paper (Owens, J. E.; Holstege, D. M.; Clifford, A. J. J. Agric. Food Chem. 2007, 55, 3292-3297). A food frequency questionnaire (FFQ) and a folate-targeted semiquantitative Block dietary folate equivalents (DFE) screener were compared and individually validated against an HT LC-MS/MS method. RBC folate was 1178 +/- 259 nmol/L (mean +/- SD) in a population of 337 normal adult subjects. Folate intakes were 556 +/- 265 microg/day by the FFQ and 524 +/- 276 microg/day by the DFE screener. Folate intakes by the DFE screener were approximately 34 microg less than by the FFQ (paired t test, p<0.01), but the intake instruments were highly correlated for total folate intake (r=0.608, p<0.01). Correlations between instruments and RBC folate were low (r<0.35) but strong (p<0.01). ROC curve analysis indicates that the measurement of RBC folate by the HT LC-MS/MS method is a better predictive tool than are intake instruments for the evaluation of marginal folate status.     

Concentrations of anthocyanins in common foods in the United States and estimation of normal consumption

Anthocyanins (ACNs) are water-soluble plant pigments that have important functions in plant physiology as well as possible health effects. Over 100 common foods were screened for ACNs, and 24 of them were found to contain ACNs. Concentrations of total ACNs varied considerably from 0.7 to 1480 mg/100 g of fresh weight in gooseberry ('Careless' variety) and chokeberry, respectively. Not only does the concentration vary, but the specific anthocyanins present in foods are also quite different. Only six common aglycones, delphinidin, cyanidin, petunidin, pelargonidin, peonidin, and malvidin, were found in all of these foods. However, their sugar moieties and acylation patterns varied from food to food. Results from this study will add to the available data for the USDA Nutrient Database of flavonoids. On the basis of the concentration data and updated food intake data from NHANES 2001-2002, the daily intake of ACNs is estimated to be 12.5 mg/day/person in the United States. Of the different aglycones, cyanidin, delphinidin, and malvidin were estimated to contribute 45, 21, and 15%, respectively, of the total ACN intake. Nonacylated contributed 77% compared to 23% from acylated ACNs.     

Heat denaturation of soy glycinin: influence of pH and ionic strength on molecular structure

The 7S/11S glycinin equilibrium as found in Lakemond et al. (J. Agric. Food Chem. 2000, 48, xxxx-xxxx) at ambient temperatures influences heat denaturation. It is found that the 7S form of glycinin denatures at a lower temperature than the 11S form, as demonstrated by a combination of calorimetric (DSC) and circular dichroism (CD) experiments. At pH 7.6, at which glycinin is mainly present in the 11S form, the disulfide bridge linking the acidic and the basic polypeptides is broken during heat denaturation. At pH 3.8, at which glycinin has dissociated partly into the 7S form, and at pH 5.2 this disruption does not take place, as demonstrated by solubility and gel electrophoretic experiments. A larger exposure of the acidic polypeptides (Lakemond et al., 2000) possibly correlates with a higher endothermic transition temperature and with the appearance of an exothermic transition as observed with DSC. Denaturation/aggregation (studied by DSC) and changes in secondary structure (studied by far-UV CD) take place simultaneously. Generally, changes in tertiary structure (studied by near-UV CD) occur at lower temperatures than changes in secondary structure.     

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.