Rapid method for the simultaneous measurement of nicotine and cotinine in urine and serum by gas chromatography-mass spectrometry

Comprehensive metabolic study of nicotine in equine plasma and urine using liquid chromatography/high-resolution mass spectrometry for the identification of unique biomarkers for doping control

Nicotine is classified as a stimulant, and its use is banned in horse racing and equestrian sports by the International Federation of Horseracing Authorities and the Fédération Équestre Internationale, respectively. Because nicotine is a major alkaloid of tobacco leaves, there is a potential risk that doping control samples may be contaminated by tobacco cigarettes or smoke during sample collection. In order to differentiate the genuine doping and sample contamination with tobacco leaves, it is necessary to monitor unique metabolites as biomarkers for nicotine administration and intake. However, little is known about the metabolic fate of nicotine in horses. This is the first report of comprehensive metabolism study of nicotine in horses. Using liquid chromatography/electrospray ionization high-resolution mass spectrometry, we identified a total of 17 metabolites, including one novel horse-specific metabolite (i.e., 4-hydroxy-4-(3-pyridyl)-N-methylbutanamide), in post-administration urine samples after nasoesophageal administration of nicotine to three thoroughbred mares; eight of these compounds were confirmed based on reference standards. Among these metabolites, N-hydroxymethylnorcotinine was the major urinary metabolite in equine, but it could only be tentatively identified by mass spectral interpretation due to the lack of reference material. In addition, we developed simultaneous quantification methods for the eight target analytes in plasma and urine, and applied them to post-administration samples to establish elimination profiles of nicotine and its metabolites. The quantification results revealed that trans-3'-hydroxycotinine could be quantified for the longest period in both plasma (72 h post-administration) and urine (96 h post-administration). Therefore, this metabolite is the most appropriate monitoring target for nicotine exposure for the purpose of doping control due to its long detection times and the availability of its reference material. Further, we identified trans-3'-hydroxycotinine as a unique biomarker allowing differentiation between nicotine administration and sample contamination with tobacco leaves.

Low cigarette smoking prevalence in peri-urban Peru: results from a population-based study of tobacco use by self-report and urine cotinine

Background

A recent study found lower self-reported prevalence of tobacco smoking in a peri-urban area of Lima, Peru than previously reported in urban samples. These regions encompass substantial proportions of Peru’s population – ones at greater risk of disease due to reduced healthcare access – but have been less often studied. We validate low smoking prevalence with urine cotinine and characterize chronic disease and lung function outcomes between non-, occasional, and daily smokers.

Methods

Data are from the CRONICAS Cohort Study, a population-based longitudinal study in four low-resource Peruvian settings, which began in 2010. Of a baseline cohort of 2978 adults, we prospectively followed 2583 (87%) to determine prevalence of chronic illness.

Results

In a baseline sub-sample of 382 participants, median adjusted cotinine was 0.0 mcg/mg (IQR 0–0) for both self-reported non-smokers and occasional smokers compared to 172.3 mcg/mg (IQR 0–709.2) for daily smokers. Creatinine-adjusted cotinine validated daily smoking prevalence of 4.7% at a cutoff of 100 mcg/mg. Kappa statistic for daily smoking and creatinine- adjusted cotinine ≥100 mcg/mg was 0.65 (95% CI 0.47, 0.83), indicating substantial agreement. At baseline, we found 3.3% daily and 8.9% occasional smoking by self-report for the full cohort. Follow-up indicated little difference in chronic disease prevalence between groups. Daily smokers trended toward having a greater decline in FVC (−1%; 95% CI -2.9, 0.8) and FEV₁ (−1.3%; 95% CI -3.2, 0.6) over 40 months when compared to non-smokers, whereas the decline in lung function for occasional smokers was similar compared to non-smokers (−0.2% FVC; 95% CI -1.5, 1.0) and (0% FEV₁; 95% CI -1.3, 1.3).

Conclusions

Our data places Peru within a previously-described pattern of smoking found in much of Latin America, favoring occasional over daily smoking and low cigarette consumption. We determine that there are not significant differences between smoking groups concerning chronic disease outcomes. We favor distinguishing between daily and occasional smokers in order to accurately characterize these low-use populations.

Electronic supplementary material

The online version of this article (doi:10.1186/s12971-017-0137-8) contains supplementary material, which is available to authorized users.

Validation of a LC-MS/MS method for quantifying urinary nicotine, six nicotine metabolites and the minor tobacco alkaloids--anatabine and anabasine--in smokers' urine

Tobacco use is a major contributor to premature morbidity and mortality. The measurement of nicotine and its metabolites in urine is a valuable tool for evaluating nicotine exposure and for nicotine metabolic profiling--i.e., metabolite ratios. In addition, the minor tobacco alkaloids--anabasine and anatabine--can be useful for monitoring compliance in smoking cessation programs that use nicotine replacement therapy. Because of an increasing demand for the measurement of urinary nicotine metabolites, we developed a rapid, low-cost method that uses isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) for simultaneously quantifying nicotine, six nicotine metabolites, and two minor tobacco alkaloids in smokers' urine. This method enzymatically hydrolyzes conjugated nicotine (primarily glucuronides) and its metabolites. We then use acetone pretreatment to precipitate matrix components (endogenous proteins, salts, phospholipids, and exogenous enzyme) that may interfere with LC-MS/MS analysis. Subsequently, analytes (nicotine, cotinine, hydroxycotinine, norcotinine, nornicotine, cotinine N-oxide, nicotine 1'-N-oxide, anatabine, and anabasine) are chromatographically resolved within a cycle time of 13.5 minutes. The optimized assay produces linear responses across the analyte concentrations typically found in urine collected from daily smokers. Because matrix ion suppression may influence accuracy, we include a discussion of conventions employed in this procedure to minimize matrix interferences. Simplicity, low cost, low maintenance combined with high mean metabolite recovery (76-99%), specificity, accuracy (0-10% bias) and reproducibility (2-9% C.V.) make this method ideal for large high through-put studies.

Cigarette smoking during pregnancy: chromosome translocations and phenotypic susceptibility in mothers and newborns

The effects of maternal cigarette smoking during pregnancy on structural chromosome aberrations were evaluated in peripheral lymphocytes from 239 mothers and their 241 newborns to determine whether smoking during pregnancy, genetic susceptibility, and race are associated with chromosome aberrations including translocations. Demographic information and cigarette smoking data were obtained via questionnaire. There were 119 Caucasian Americans, 118 African Americans, and 2 Asian Americans. The average maternal age was 24.9+/-5.8 (mean+/-S.D.) years. Thirty-nine percent of the Caucasian Americans and 45.4% of the African Americans self-reported that they were active smokers during the index pregnancy. The average number of cigarettes smoked per day was 2.65+/-5.75 and 1.37+/-3.17 for Caucasian and African American mothers, respectively. Peripheral blood lymphocytes from the mother and from the fetal side of the placenta were evaluated for chromosome aberrations by whole chromosome painting. Aliquots from the same blood samples were also used to assess genetic susceptibility with an in vitro bleomycin challenge assay. Spontaneous translocation frequencies in both maternal and newborn lymphocytes were not associated with cigarette smoking, socioeconomic status, or education. The absence of a smoking effect may be attributable to the low level of cigarette usage in these subjects. The average bleomycin-induced damage in the maternal and newborn populations was 0.37+/-0.27 and 0.15+/-0.14 breaks per cell, respectively, a difference that was highly significant (p<0.0001). In newborns there was a positive association between bleomycin sensitivity and the frequencies of aberrations as measured by chromosome painting: p Collapse

Key Words

• cigarette smoking
• pregnancy
• newborns
• mothers
• chromosome translocations
• genomic susceptibility

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MESH Headings

• Adolescent
• Adult
• Black or African American
• Chromobacterium
• Female
• Humans
• Infant, Newborn
• Male
• Maternal-Fetal Exchange
• Pregnancy
• Smoking/adverse effects
• Translocation, Genetic/genetics
• White People

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Grants

• R01 DE033016 NIDCR NIH HHS
• ZIJ BC011218-01 Intramural NIH HHS
• R01 HD33016 NICHD NIH HHS

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Affiliation(s)

L Michelle Bennett Physical and Life Sciences Directorate, L-452, Lawrence Livermore National Laboratory, Livermore, CA 94550, United States.
Yun Wang
Marilyn J Ramsey
Gail F Harger
William L Bigbee
James D Tucker

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Simultaneous and sensitive measurement of nicotine, cotinine, trans-3'-hydroxycotinine and norcotinine in human plasma by liquid chromatography-tandem mass spectrometry

An LC-MS/MS method for the simultaneous quantification of nicotine, cotinine, trans-3'-hydroxycotinine and norcotinine in human plasma was developed and fully validated. Potential endogenous and exogenous interferences were extensively evaluated and limits of quantification were determined by decreasing analyte concentration. Analytical ranges were 1-500 ng/mL for nicotine and cotinine, 5-500 ng/mL for trans-3'-hydroxycotinine and norcotinine. Mean intra- and inter-assay analytical recoveries were between 101.9 and 116.8%, and intra- and inter-assay imprecision were less than 11% RSD for all analytes: parameters were evaluated at three different concentrations across the linear range of the assay. Extraction efficiency was > or = 70% for all analytes. This validated method is useful for the determination of nicotine and metabolites in human plasma to support research on the role of nicotine biomarkers on neuronal systems mediating cognitive and affective processes and to differentiate active, passive and environmental exposure.

Antidepressant-like effects of nicotine and reduced nicotinic receptor binding in the Fawn-Hooded rat, an animal model of co-morbid depression and alcoholism

A strong positive association between depression and alcoholism is evident in epidemiological studies. Curiously, the incidence of smoking (nicotine intake) is also very high among depressed individuals. Because neuronal nicotinic receptors have been implicated in mood regulation as well as in reinforcing effects of alcohol, it was of interest to determine whether inherent changes in these receptors may be manifested in an animal model that expresses both depressive-like characteristics and high alcohol intake. Thus, Fawn-Hooded (FH) rats along with their control ACI rats were used to measure the density of the high affinity nicotinic receptor in discrete brain regions. Furthermore, the effects of acute and chronic nicotine on depressive-like characteristics of FH rats were also evaluated. Measurements of [(3)H]cytisine binding (selective for alpha4beta2 nicotinic receptor subtype) revealed a reduction in these receptors only in the striatum of FH rats, a result very similar to that observed in selectively-bred alcohol-preferring (P) rats. Administration of nicotine acutely (0.4 mg/kg, sc) resulted in a significant reduction of immobility in the forced swim test (FST) in FH rats only, implying an antidepressant-like effect of nicotine. Another group of FH rats were administered 0.4 mg/kg nicotine (daily, sc) for 14 days and their behavior in the FST was evaluated 22-24 h after the last injection. In this case, nicotine also had a significant antidepressant-like effect in FH rats suggesting no tolerance to nicotine had occurred. The effects of nicotine on FST behavior are very similar to those observed in Flinders Sensitive Line rats, a putative animal model of depression. Together, these findings provide additional evidence for antidepressant-like effects of nicotine and strengthen the postulated association between striatal nicotinic receptors and high alcohol intake. Thus, nicotinic receptors could be suitable targets for the development of novel pharmacotherapy for treatment of depression and possibly alcoholism.

Cell proliferation kinetics and genotoxicity in lymphocytes of smokers living in Mexico City

Genotoxicity caused by tobacco smoke was assessed in peripheral blood lymphocytes of smokers living in Mexico City by determining sister chromatid exchange (SCE), cell proliferation kinetics (CPK), replication index (RI) and mitotic index (MI). Nicotine levels, and its major metabolite cotinine, were also estimated in urine samples using gas-chromatography-mass spectrometry to quantify smoking intensity. The outcome of the analysis and the comparison of the 77-smoker group with a non-smoking control group showed that moderate and heavy smokers exhibited significant differences (P < 0.001 and P < 0.05, respectively) in CPK, with an underlying delay in the cellular cycle; similarly, RI was significantly different in these groups (P < 0.001 and P < 0.0001, respectively). There were significant correlations (P < 0.05) between age and number of years the subject had been smoking, as well as between RI and nicotine and cotinine levels and between CPK (M1, M2 and M3) and nicotine and cotinine levels. Smokers were classified for the analysis according to the nicotine levels (it is in relation to number of cigarettes smoked per day) found in urine (ng/mL) as: light (10-250), moderate (251-850) and heavy (851-4110). Significant differences in CPK were found (P < 0.05) between moderate and heavy smokers and non-smokers. Significant differences in RI were found between moderate (P < 0.001) and heavy smokers (P < 0.0001) and non-smokers, but not for the light smoking group. MI was determined in 57 of the smokers, whereas SCE frequency was only recorded in 34 smokers. Both parameters yielded no significant differences, nor correlations with any of the assessed variables. In conclusion, cytokinetic and cytostatic effects were mainly detected in heavy and moderate smokers. Cell cycle delay and RI decrease were found in all ;healthy' smokers. The nicotine and cotinine exposure (causing oxidative damage to DNA) may have implications in the decrease in cell replication due to direct damage to DNA and/or a decrease in the DNA repair mechanisms. Alternatively, nicotine and cotinine may possibly induce apoptosis.

The effects of smoking cessation counseling by midwives on Dutch pregnant women and their partners

OBJECTIVE

Smoking during pregnancy is an important problem in the Netherlands. We tested the effectiveness of a health counseling method by midwives using a RCT.

METHODS

Four provinces with 42 practices including 118 midwives were randomly assigned to the experimental or control condition. Midwives in the experimental group provided brief health counseling, self-help materials on smoking cessation during pregnancy and early postpartum, and a partner booklet. Controls received routine care. The main outcome measures were 7-day abstinence, continuous abstinence, and partner smoking at 6 weeks post-intervention (T1) and 6 weeks postpartum (T2).

RESULTS

Multi-level analysis revealed significant differences between both conditions at T1 and T2 using intention-to-treat analysis. Nineteen percent of the experimental group reported 7-day abstinence compared to 7% of the control group at T1, and 21 and 12%, respectively, at T2. For continuous abstinence these percentages were 12% in the experimental group and 3% in the control group. The partner intervention was not successful.

CONCLUSION

The intervention resulted in significant effects on smoking behavior for pregnant women, but not for partner smoking.

PRACTICE IMPLICATIONS

The program realized short-term effects. An important precondition is that midwives need a proper training.

Quantitative analysis of trimethylsilyl derivative of hydroxyurea in plasma by gas chromatography–mass spectrometry

Hydroxyurea is an antitumor drug widely used in the treatment of sickle cell disease. The drug has been analyzed in biological fluids by a number of high-performance liquid chromatography (HPLC) methods. This paper describes a fast and highly reliable capillary gas chromatography-mass spectrometry (GC-MS) procedure that was developed for the detection and quantitation of hydroxyurea in plasma. The compound and its labeled internal standard were liquid extracted from plasma and derivatized with BSTFA before analysis. The detection limit of the assay was 0.078 microg/ml and the limit of quantitation was 0.313 microg/ml with linearity up to 500 microg/ml. Intra-day variation, as coefficient of variation (C.V., %) over the selected concentration range, was 0.3-8.7% and inter-day variation was 0.4-9.6%.

A new molecularly imprinted polymer for selective extraction of cotinine from urine samples by solid-phase extraction

Cotinine, the main metabolite of nicotine in human body, is widely used as a biomarker for assessment of direct or passive exposure to tobacco smoke. A method for molecularly imprinted solid-phase extraction (MISPE) of cotinine from human urine has been investigated. The molecularly imprinted polymer (MIP) with good selectivity and affinity for cotinine was synthesized using cotinine as the template molecule, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate as the cross-linker. The imprinted polymer was evaluated for use as a SPE sorbent, in tests with aqueous standards, by comparing recovery data obtained using the imprinted form of the polymer and a non-imprinted form (NIP). Extraction from the aqueous solutions resulted in more than 80% recovery. A range of linearity for cotinine between 0.05 and 5 microg mL-1 was obtained by loading 1 mL blank urine samples spiked with cotinine at different concentrations in acetate buffer of pH 9.0, and by using double basic washing and acidic elution. The intra-day coefficient of variation (CV) was below 7% and inter-day CV was below 10%. This investigation has provided a reliable MISPE-HPLC method for determination of cotinine in human urine from both active smokers and passive smokers.

Clinical correlation between the consumption of nicotine and cotinine concentrations in urine and serum by competitive enzyme-linked immunosorbent assay

Different negative effects of smoking are known (e.g. postoperative complications), which lead, especially in plastic surgery, to unsatisfactory results. The aim of this study was to examine the appropriateness of a cotinine enzyme-linked immunosorbent assay (ELISA) for routine usage in operative disciplines. By correlation of smoking habits and concentration of cotinine in serum and urine, we tried to ascertain reference values for smokers, passive smokers and non-smokers. The reliability and sensitivity of the cotinine ELISA concerning nicotine exposure need to be proven. 165 (108 men, 57 women) test persons were examined by detecting cotinine in serum and urine by ELISA. The study shows a very good sensitivity, precision and reproducibility of the cotinine ELISA according to the laboratory criteria. The test shows significance of a good differentiation between smokers, passive smokers and non-smokers in urine. In serum, cotinines are excellent to differentiate between smokers and non-smokers/passive smokers. Urine and serum tests demonstrate valid and comparable results.

The Measurement of Nicotine in Human Plasma by High-Performance Liquid Chromatography-Electrospray-Tandem Mass Spectrometry

The authors describe a reverse-phase high-performance liquid chromatography-electrospray-tandem mass spectrometry method for the measurement of nicotine in human plasma. Samples (500 microL) with added deuterium-labeled d3-nicotine as an internal standard (IS) were treated with a 2-step process of ether extraction (6 mL) followed by back-extraction into 0.1% formic acid (50 microL). Chromatography was performed on a phenyl Novapak column with a mobile phase consisting of 50% 10 mM ammonium formate (pH 3.3) and acetonitrile (50:50, vol/vol). A flow rate of 0.2 mL/min resulted in a total analysis time of 5 minutes per sample. Mass spectrometric detection was by selected reactant monitoring (nicotine m/z 163.2 --> 130.2; IS m/z 166.2 --> 87.2). The assay was linear from 0.5 to 100 microg/L (r > 0.993, n = 9). The accuracy and imprecision of the method for quality control samples were 87.5% to 113% and <10.2%, respectively. Interday accuracy and imprecision at the limit of quantification (0.5 microg/L) was 113% and 7.2% (n = 4). The process efficiency for nicotine in plasma was >75%. The method described has good process efficiency, stabilized nicotine, avoided concentration steps, and most importantly minimized potential contamination. Further, we have established that water-based standards and controls are interchangeable with plasma-based samples. This method was used successfully to measure the pharmacokinetic profiles of subjects involved in the development of an aerosol inhalation drug delivery system.

Cigarette smoking: Evidence to guide measurement

Smoking cessation programs measure outcomes in terms of abstinence from or reduction in smoking. These outcomes can be measured through self-report by the smoker, through measurement with a biological marker of smoking, or through a combination of both. Consideration of the relative advantages of self-report and biomarker approaches is important in the selection of measurement strategies to evaluate outcomes in smoking cessation interventions. In this article both ways of measuring smoking behavior, self-report and biomarkers of carbon monoxide, cotinine, nicotine, thiocyanate, and alkaloids of nicotine, are explored. Measurement approaches are discussed in light of research evidence and their physiologic bases.

Intérêt des différents marqueurs biologiques dans l'évaluation du tabagisme

Tobacco exposure can be assessed by the measurement of several markers in biological fluids. These markers are more or less specific for tobacco and the different methods to measure them out differ in terms of sensibility, specificity, ease of use and cost. The clinician prescribing a dosage for a patient has to take all these parameters into account to make an accurate choice. In this article, we have analysed the usefulness of the main biological tobacco markers in the follow-up of smokers and compared their methods of dosage. We propose several indications and point out the interest of relevant markers to realize objective measurements of smoking habits.

Determination of nicotine and its metabolites in urine by solid-phase extraction and sample stacking capillary electrophoresis-mass spectrometry

The combination of capillary electrophoresis (CE) and mass spectrometry (MS) with solid-phase extraction (SPE) has been used for the identification of nicotine and eight of its metabolites in urine. The recovery of cotinine from cotinine-spiked urine, by C18 SPE, was found to be 98%. Smokers urine (200 ml) was preconcentrated 200-fold via SPE prior to analysis. The sample stacking mode of CE, when compared to capillary zone electrophoresis, was shown to improve peak efficiency by 132-fold. The combination of hydrodynamic and electrokinetic injection was studied with sample stacking/CE/MS. The on-column limits of detection (LOD) of nicotine and cotinine, by this technique, were found to be 0.11 and 2.25 microg/ml, respectively. Hence, LODs of nicotine and cotinine in urine after 200-fold preconcentration were 0.55 and 11.25 ng/ml, respectively.

Sensitive and simple method for the determination of nicotine and cotinine in human urine, plasma and saliva by gas chromatography-mass spectrometry

A method is proposed for the determination of nicotine and cotinine in human urine, plasma and saliva. Nicotine and cotinine were extracted from alkalinized sample with ethyl ether and concentrated to minimum volume with nitrogen stream. The volatility of nicotine was prevented by the addition of acetic acid to the organic solvent during evaporation. Peak shapes and quantitation of nicotine and cotinine are excellent, with linear calibration curves over a wide range of 1-10,000 ng/ml. The detection limits of nicotine and cotinine are 0.2 ng/ml in urine and 1.0 ng/ml in plasma and saliva. The intra-day precision of nicotine and cotinine in all samples was <5% relative standard deviation (RSD). Urine, plasma and saliva samples of 303 non-smoking and 41 smoking volunteers from a girl's high school in Korea were quantified by the described procedure. As a result, the concentrations of nicotine and cotinine in plasma ranged from 6 to 498 ng/ml and 4 to 96 ng/ml. Otherwise, those of nicotine and cotinine in saliva ranged from 0 to 207 ng/ml and 0 to 42 ng/ml, and those of nicotine and cotinine in urine ranged from 0 to 1,590 ng/ml and 0 to 2,986 ng/ml, respectively. We found that the concentration of cotinine in plasma was successfully predicted from the salivary cotinine concentration by the equation y=2.31x+4.76 (x=the concentration of cotinine in saliva, y=the concentration of cotinine in plasma). The results show that through the accurate determination of cotinine in saliva, the risk of ETS-exposed human can be predicted.

Studies on the interactions of tobacco leaf and tobacco smoke constituents and monoamine oxidase

Studies have demonstrated that smokers have lower levels of brain monoamine oxidase (MAO) A and B activity and lower MAO-B platelet activity than non-smokers. Recent speculations suggest that in addition to nicotine, tobacco components which are MAO inhibitors, may contribute to some tobacco related psychopharmacological effects. Furthermore, epidemiological evidence indicates a lower incidence of Parkinson's disease in smokers than in non-smokers. This relationship also might be linked to MAO inhibition. These intriguing observations prompted studies on the effects of tobacco leaf and tobacco smoke constituents on MAO activity. Studies reported here demonstrate that crude hexane tobacco leaf and hexane and aqueous leaf extracts have MAO inhibitory properties. Rat brain mitochondrial MAO-A and MAO-B activity are not altered following continuous 28 day exposure to (osmotic minipump) to two tobacco alkaloids, (S)-nicotine or (R,S)-N-methylanatabine. However, earlier studies in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treated parkinsonian C57BL/6 mouse model have provided indirect evidence that the tobacco derived 2,3,6-trimethyl-1,4-naphthoquinone (an MAO-A and B inhibitor) is effective in inhibiting MAO-B in vivo and is neuroprotective. Results reported here from more extensive tobacco leaf extractions provide evidence for three additional compounds with MAO-B inhibitory properties. One contains a chromone system, another a polyunsaturated macro-cycle and the third we have identified as farnesylacetone. These findings provide support to the thesis that components of tobacco smoke may be responsible for the inhibition of brain MAO-A and brain and platelet MAO-B in human smokers.

Quantification of nicotine, chlorpyrifos and their metabolites in rat plasma and urine using high-performance liquid chromatography

This study describes a high-performance liquid chromatographic method for the separation and quantification of nicotine, its metabolites nornicotine and cotinine, the insecticide chlorpyrifos (O,O-diethyl-O[3,5,6-trichloro-2-pyridinyl]phosphorothioate), and its metabolites chlorpyrifos-oxon (O,O-diethyl-O[3,5,6-trichloro-2-pyridinyl]phosphate), and TCP (3,5,6-trichloro-2-pyridinol) in rat plasma and urine. The compounds were separated using gradient mobile phase of methanol, acetonitrile and water (pH 3.20) at a flow-rate of 0.8 ml/min in a period of 17 min, and gradient UV detection ranging between 260 and 280 nm. The retention times ranged from 3.4 to 16.7 min. The limits of detection were ranged between 20 and 150 ng/ml, while limits of quantitation were 50-200 ng/ml. Average percentage recovery of five spiked plasma samples were 84.7+/-8.3, 78.2+/-7.6, 80.1+/-7.6, 79.0+/-6.4, 74.0+/-7.4, 87.6+/-7.5, and from urine 85.1+/-5.2, 75.9+/-7.0, 82.1+/-6.1, 79.5+/-6.1, 71.3+/-7.4 and 81.3+/-6.9 for nicotine, nornicotine, cotinine chlorpyrifos, chlorpyrifos-oxon and TCP, respectively. Intra-day accuracy and precision for this method were ranged between 2.2-3.6 and 2.1-2.8%, respectively. The relationship between peak areas and concentration was linear over range between 200 and 2000 ng/ml. This method was applied to analyze the above chemicals and metabolites following combined oral administration in rats.

A study of a new TSM bio-mimetic sensor using a molecularly imprinted polymer coating and its application for the determination of nicotine in human serum and urine

A new bio-mimetic quartz crystal thickness-shear-mode (TSM) sensor, using an imprinted polymer coating as the sensitive material, has been fabricated and applied to the determination of nicotine (NIC) in human serum and urine. The molecularly imprinted polymer (MIP) was synthesized using NIC as the template molecule and methacrylic acid (MAA) as the functional monomer. The sensor showed high selectivity and a sensitive response to NIC in aqueous system. The linear response range of the sensor was between 5.0 x 10(-8) and 1.0 x 10(-4) M with a detection limit of 2.5 x 10(-8) M. The viscoelasticity of the coating in the air and in liquid has been studied by the impedance spectrum. The MIP sensor was stable and exhibited effective reproducibility. Satisfactory results were achieved in the detection of the real samples.

The miseries of passive smoking

Passive smoking is defined as an involuntary exposure to a combined but diluted cigarette sidestream smoke (SS, gas and particle phases that are evolved from the smoldering end of a cigarette while the smoker is not puffing) and the exhaled smoke from smokers. SS contains numerous cytotoxic substances such as polycyclic aromatic hydrocarbons (PAHs), aromatic amines, nitrosamines, heavy metals, poisonous gases, pesticide residues, and radioactive elements in quantities much higher than those found from the cigarette mainstream smoke (MS) which is puffed by smokers. Passive smoking is found to be the cause of death from cancers and cardiac disease. Furthermore, it damagingly involves reproductive organs, the nervous system, genetic materials, and is particularly hazardous to mother and child during pregnancy and to those with a history of asthma, chronic infections, induced or earned immune deficiency, or predisposed susceptibility.

Application of liquid separation techniques to the determination of the main urinary nicotine metabolites

A rapid procedure for the analysis of the main nicotine metabolites (cotinine, trans-3'-hydroxycotinine) in urine has been worked out. The procedure includes isolation of nicotine and its metabolites from urine by means solid-liquid extraction technique using resin Amberlite XAD-2 and then quantitation by the use of thin-layer chromatography with densitometry (in reflection mode). GC-MS was applied to confirm the results obtained by TLC. The procedure was applied to the analysis of cotinine concentrations in urine samples taken from children living in Upper Silesia region (Poland). Among 444 investigated children we did not find cotinine almost in 60% but in 15% of this population, there were children who could have been exposed to cigarette smoke.

Particle counting immunoassay for urinary cotinine. Comparison with chromatography, enzyme-linked immunoassay and fluorescence polarization immunoassay

Urinary cotinine was measured according to its inhibitory activity on the agglutination of cotinine-coated latex particles by anti-cotinine antibodies, the agglutination being measured by optical counting of the remaining non-agglutinated particles (particle counting, PaC). The detection limit was 0.03 microgram/ml and the practical range extended from 0.03 to 3.9 micrograms/ml. The correlation results of 320 urine samples with those of high pressure liquid chromatography, enzyme-linked (Coti-Tracq EIA, Serex Inc., Maywood, NJ, USA), and fluorescence polarization immunoassay (TDX instrument, Abbott, Abbott Park, IL, USA) were r = 0.90, r = 0.69, r = 0.87, respectively, whereas the correlation coefficients between the assays other than particle counting ranged from 0.62 to 0.88. PaC does not require any separation step and can thus be easily automated.