Selective hair analysis of nicotine by molecular imprinted solid-phase extraction: An application for evaluating tobacco smoke exposure

Determination of nicotine and cotinine in human hair using online solid phase extraction coupled with liquid chromatography-tandem mass spectrometry and their relation to hair cortisol and cortisone

Tobacco smoking is one of the critical public health threats all over the world. Since nicotine and its metabolite cotinine have been routinely used as the biomarkers to estimate the exposure to tobacco smoking, hair nicotine and cotinine analyses can provide of a retrospective index of nicotine and cotinine integrated over extended periods of several months prior to hair sampling to estimate the long-term exposure to tobacco smoking. Since the relationship between tobacco smoking and hypothalamic-pituitary-adrenal (HPA) axis is implicated in both stress response and nicotine addiction, better understanding of the association between hair nicotine, cotinine levels and hair cortisol, cortisone levels is an important prerequisite toward more adequate use of this method in future research. We here presented an online solid phase extraction (SPE) coupled with liquid chromatography- tandem mass spectrometry (LC-MS/MS) method for quantification of long-term integrated nicotine and cotinine in human hair. This method was applied to the analysis of hair nicotine and cotinine in 40 participants of smokers and nonsmokers (mean ± SD age: 46.25 ± 11.92 years; 40 % male) and the investigation of their association with hair cortisol and cortisone. Methanol together with glass tube was used for hair nicotine and cotinine extraction during the incubation time of 18-h. The limits of quantification were 1 pg/mg for nicotine as well as 0.1 pg/mg for cotinine. The inter- and intra-day coefficients of variation were below 15 %. The method recovery ranged between 90 % and 104 %. Group-level analyses revealed that smokers exhibited higher hair nicotine and cotinine levels compared to nonsmokers. Hair nicotine and cotinine levels showed significant positive associations with hair cortisol and cortisone levels in smokers (nicotine and cortisol: Spearman's ρ = 0.619, p = 0.005; cotinine and cortisol: Spearman's ρ = 0.468, p = 0.043; nicotine and cortisone: Spearman's ρ = 0.773, p = 0.000; cotinine and cortisone: Spearman's ρ = 0.531, p = 0.016), but not in nonsmokers. The presented online SPE LC-MS/MS method provides a simply and highly specific analytical strategy for the detection of nicotine and cotinine concentrations in human hair for the retrospective assessment of cumulative long-term nicotine and cotinine exposure. Furthermore, hair nicotine, cotinine levels correlate with hair cortisol, cortisone levels in smokers other than nonsmokers.

Advancing the use of molecularly imprinted polymers in bioanalysis: the selective extraction of cotinine in human urine

Aim: To characterize a molecularly imprinted polymer via precipitation polymerization for the extraction of cotinine in urine. Methods: The polymer was created via precipitation polymerization. Physical characteristics of the polymer were assessed via scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis. The polymer adsorption capacity was assessed and an solid-phase extraction method from urine by LC-MS/MS was developed. Results: The polymer had small, spherical morphology and little thermal decomposition. The extraction method yielded cotinine recoveries of 77-103% in urine. The molecularly imprinted polymer adsorption capacity for cotinine was 448.2 ± 2.1 μg/mg. Common interferants did not affect cotinine's extraction. Conclusion: The resulting polymer was determined to be specific for cotinine and can be used for the detection of cotinine in urine for clinical samples.

Molecularly imprinted polymers as a selective sorbent for forensic applications in biological samples-a review

Molecularly imprinted polymers (MIP) consist of a molecular recognition technology with applicability in different areas, including forensic chemistry. Among the forensic applications, the use of MIP in biological fluid analysis has gained prominence. Biological fluids are complex samples that generally require a pre-treatment to eliminate interfering agents to improve the results of the analyses. In this review, we address the development of this molecular imprinting technology over the years, highlighting the forensic applications of molecularly imprinted polymers in biological sample preparation for analysis of stimulant drugs such as cocaine, amphetamines, and nicotine.

Growing Trends in the Efficient and Selective Extraction of Compounds in Complex Matrices Using Molecularly Imprinted Polymers and Their Relevance to Toxicological Analysis

In the world of forensic and clinical toxicology, proper sample preparation is one of the key steps in identification and quantification of drugs of abuse. Traditional extraction methods such as solid-phase extraction and liquid-liquid extraction are often laborious and nonselective for the target analytes being measured. Molecularly imprinted polymers (MIPs) can be synthesized for sample extraction and their versatility allows the polymer to be employed in off-line, benchtop extractions or on/in-line instrument extractions, offering a faster and more selective sample preparation without the risk of interfering matrix effects. This review details the synthesis and applications of MIP materials for the extraction of drug compounds from biological matrices in publications from 1994 to today.

Selective removal of nicotine from the main stream smoke by using a surface-imprinted polymer monolith as adsorbent

Using molecularly imprinted polymer as a selective adsorbent for gaseous toxicants is a novel attempt. In present work, a nicotine surface-imprinted monolith (MIM) was used for the selective removal of nicotine from smoke. First, the retention capacity and selectivity for this MIM was tested by using it as the stationary phase in gas chromatography and chromatographic conditions optimized. Then, the gas phase adsorption isotherms of MIM were constructed and the adsorption thermodynamics explored. At last, the applicability for MIM in the removal of nicotine in smoke was explored. Results indicated a stronger retention capacity and a higher selectivity of MIM toward the template vapor, with a capacity factor (87.88) and a selectivity factor (10.15) under the optimized conditions. A higher standard adsorption enthalpy change for this MIM toward the template (ΔH_a⁰ = 65.53 kJ mol^-1) than that for the non-imprinted monolith (NIM) column (ΔH_a⁰ = 47.46 kJ mol^-1) was observed. The adsorption isotherm for MIM appears the BET type II shape, while that for the NIM was approximately linear. When this MIM was used as the adsorbent, it exhibited a high performance in the selective removal of nicotine from the main stream smoke, with an adsorption percentage of 99.43%.

Metabolomics of Pregnancy Complications: Emerging Application of Maternal Hair

In recent years, the study of metabolomics has begun to receive increasing international attention, especially as it pertains to medical research. This is due in part to the potential for discovery of new biomarkers in the metabolome and to a new understanding of the "exposome", which refers to the endogenous and exogenous compounds that reflect external exposures. Consequently, metabolomics research into pregnancy-related issues has increased. Biomarkers discovered through metabolomics may shed some light on the etiology of certain pregnancy-related complications and their adverse effects on future maternal health and infant development and improve current clinical management. The discoveries and methods used in these studies will be compiled and summarized within the following paper. A further focus of this paper is the use of hair as a biological sample, which is gaining increasing attention across diverse fields due to its noninvasive sampling method and the metabolome stability. Its significance in exposome studies will be considered in this review, as well as the potential to associate exposures with adverse pregnancy outcomes. Currently, hair has been used in only two metabolomics studies relating to fetal growth restriction (FGR) and gestational diabetes mellitus (GDM).

Molecular Imprinting Applications in Forensic Science

Producing molecular imprinting-based materials has received increasing attention due to recognition selectivity, stability, cast effectiveness, and ease of production in various forms for a wide range of applications. The molecular imprinting technique has a variety of applications in the areas of the food industry, environmental monitoring, and medicine for diverse purposes like sample pretreatment, sensing, and separation/purification. A versatile usage, stability and recognition capabilities also make them perfect candidates for use in forensic sciences. Forensic science is a demanding area and there is a growing interest in molecularly imprinted polymers (MIPs) in this field. In this review, recent molecular imprinting applications in the related areas of forensic sciences are discussed while considering the literature of last two decades. Not only direct forensic applications but also studies of possible forensic value were taken into account like illicit drugs, banned sport drugs, effective toxins and chemical warfare agents in a review of over 100 articles. The literature was classified according to targets, material shapes, production strategies, detection method, and instrumentation. We aimed to summarize the current applications of MIPs in forensic science and put forth a projection of their potential uses as promising alternatives for benchmark competitors.

A simultaneous analysis method of polycyclic aromatic hydrocarbons, nicotine, cotinine and metals in human hair

Polycyclic aromatic hydrocarbons (PAHs), nicotine, cotinine, and metals in human hair have been used as important environmental exposure markers. We aimed to develop a simple method to simultaneously analyze these pollutants using a small quantity of hair. The digestion performances of tetramethylammonium hydroxide (TMAH) and sodium hydroxide (NaOH) for human hair were compared. Various solvents or their mixtures including n-hexane (HEX), dichloromethane (DCM) and trichloromethane (TCM), HEX:DCM32 (3/2) and HEX:TCM73 (7/3) were adopted to extract organics. The recoveries of metals were determined under an optimal operation of digestion and extraction. Our results showed that TMAH performed well in dissolving human hair and even better than NaOH. Overall, the recoveries for five solutions were acceptable for PAHs, nicotine in the range of 80%-110%. Except for HEX, other four extraction solutions had acceptable extraction efficiency for cotinine from HEX:TCM73 (88 ± 4.1%) to HEX:DCM32 (100 ± 2.8%). HEX:DCM32 was chosen as the optimal solvent in consideration of its extraction efficiency and lower density than water. The recoveries of 12 typical major or trace metals were mainly in the range of 90%-110% and some of them were close to 100%. In conclusion, the simultaneous analysis of PAHs, nicotine, cotinine, and metals was feasible. Our study provided a simple and low-cost technique for environmental epidemiological studies.

Synthesis, characterization, and determination of genotoxic effect of a novel dimeric 8-hydroxyquinoline Cd(II) SCN complex

In this study, a Cd(II) complex was synthesized using 8-hydroxyquinoline and thiocyanate as the ligands and structurally characterized with the combination of FTIR, ¹H-NMR, ¹³C-NMR, UV-vis, and MS spectral data. Then, genotoxic effects of the prepared complex were investigated. Genotoxic properties of the dimeric 8-hydroxyquinolinthiocyanatoCd(II) [Cd₂(8Q)₂(SCN)₂] complex synthesized as drug raw material were analyzed in human peripheral blood lymphocytes. Concentrations of 1, 2, 4, 6, and 8 μg/mL [Cd₂(8Q)₂(SCN)₂] were used for 24 and 48  h durations. [Cd₂(8Q)₂(SCN)₂] significantly increased chromosomal aberrations (CAs) at 4, 6, and 8 μg/mL concentrations after a 24- h period and 2 and 4 μg/mL after a 48-h period. [Cd₂(8Q)₂(SCN)₂] significantly decreased the mitotic index (MI) at all concentrations, both at 24 and 48 h. Micronuclei frequency (MN) was not affected by [Cd₂(8Q)₂(SCN)₂] treatment compared with the control. After application for a 48 h period, 6 and 8 μg/mL concentrations showed toxic effects both in chromosomal abnormality and in micronucleus tests. It also decreased the cytokinesis-block proliferation index (CBPI), but this result was statistically significant only at 6 and 8 μg/mL concentrations. In the comet assay (single-cell gel electrophoresis (SCGE)), significant increases in comet tail length, tail moment, and tail intensity were observed at all concentrations. [Cd₂(8Q)₂(SCN)₂] displays clastogenic effect in the concentrations used in human peripheral lymphocytes at chromosomal abnormality, micronucleus tests, and cytokinesis-block proliferation index parameters. Further studies should be conducted in other test systems to evaluate the complete genotoxic potential of [Cd₂(8Q)₂(SCN)₂].

Molecular imprinting science and technology: a survey of the literature for the years 2004-2011

Herein, we present a survey of the literature covering the development of molecular imprinting science and technology over the years 2004-2011. In total, 3779 references to the original papers, reviews, edited volumes and monographs from this period are included, along with recently identified uncited materials from prior to 2004, which were omitted in the first instalment of this series covering the years 1930-2003. In the presentation of the assembled references, a section presenting reviews and monographs covering the area is followed by sections describing fundamental aspects of molecular imprinting including the development of novel polymer formats. Thereafter, literature describing efforts to apply these polymeric materials to a range of application areas is presented. Current trends and areas of rapid development are discussed.

Analysis of alkaloids from different chemical groups by different liquid chromatography methods

Alkaloids are biologically active compounds widely used as pharmaceuticals and synthesised as secondary methabolites in plants. Many of these compounds are strongly toxic. Therefore, they are often subject of scientific interests and analysis. Since alkaloids — basic compounds appear in aqueous solutions as ionized and unionized forms, they are difficult for chromatographic separation for peak tailing, poor systems efficiency, poor separation and poor column-to-column reproducibility. For this reason it is necessity searching of more suitable chromatographic systems for analysis of the compounds. In this article we present an overview on the separation of selected alkaloids from different chemical groups by liquid chromatography thus indicating the range of useful methods now available for alkaloid analysis. Different selectivity, system efficiency and peaks shape may be achieved in different LC methods separations by use of alternative stationary phases: silica, alumina, chemically bonded stationary phases, cation exchange phases, or by varying nonaqueous or aqueous mobile phase (containing different modifier, different buffers at different pH, ion-pairing or silanol blocker reagents). Developments in TLC (NP and RP systems), HPLC (NP, RP, HILIC, ion-exchange) are presented and the advantages of each method for alkaloids analysis are discussed.

Behavior of phenols and phenoxyacids on a bisphenol-A imprinted polymer. Application for selective solid-phase extraction from water and urine samples

A molecularly imprinted polymer (MIP), obtained by precipitation polymerisation with 4-vinylpyridine as the functional monomer, ethylene glycol dimethacrylate as cross-linker, and bisphenol-A (BPA) as template, was prepared. The binding site configuration of the BPA-MIP was examined using Scatchard analysis. Moreover, the behaviour of the BPA-MIP for the extraction of several phenolic compounds (bisphenol-A, bisphenol-F, 4-nitrophenol, 3-methyl-4-nitrophenol) and phenoxyacid herbicides such as 2,4-D, 2,4,5-T and 2,4,5-TP has been studied in organic and aqueous media in the presence of other pesticides in common use. It was possible to carry out the selective preconcentration of the target analytes from the organic medium with recoveries of higher than 70%. In an aqueous medium, hydrophobic interactions were found to exert a remarkably non-specific contribution to the overall binding process. Several parameters affecting the extraction efficiency of the BPA-MIP were evaluated to achieve the selective preconcentration of phenols and phenoxyacids from aqueous samples. The possibility of using the BPA-MIP as a selective sorbent to preconcentrate these compounds from other samples such as urine and river water was also explored.

Rapid and sensitive determination of nicotine in formulations and biological fluid using micellar liquid chromatography with electrochemical detection

Nicotine can be determined in pharmaceuticals and biological fluids by micellar liquid chromatography (MLC) using a C18 column, a mobile phase containing sodium dodecyl sulphate 0.15M-6% (v/v) pentanol-NaH(2)PO(4) 0.01 M (pH 6)-KCl 0.001 M, with electrochemical detection at 0.8 V. In the optimization step, the influence of the modifiers propanol, butanol and pentanol, and the voltage has been studied. With the proposed method the analysis time is below than 8 min, linearity better than 0.999, limits of detection and quantification (ng/ml) was 4 and 12 respectively, repeatability and intermediate precision below 1.8%, and all these parameters are adequate for the quantification of nicotine in chewing gum, dermal patches, tobacco and serum samples either by a pharmacologist, pathologist or toxicologist.

Uptake of nicotine from suspension culture of Nicotiana tabacum by molecularly imprinted polymers

OBJECTIVES

The aim was to use molecularly imprinted polymers (MIPs) for the selective recovery of nicotine in plant cell cultures. MIPs can selectively uptake nicotine from suspension cultures of N. tabacum, and therefore may be useful for improving levels of secondary metabolites in plant cell cultures.

METHODS

Suspension cultures of N. tabacum were initiated from callus and maintained in liquid Murashige and Skoog (MS) media containing 3% w/v sucrose, 0.1 mg/l alpha-naphthaleneacetic acid acid (NAA) and 0.25 mg/l kinetin. Tween 80 at 1% was used for permeabilisation of cell cultures. Pre-weighed XAD-2 and two types of synthesized polymers, MIPs (A and B with one and two functional monomers, respectively) and corresponding non-imprinted polymers (NIPs), A and B, were introduced aseptically into the permeabilised suspension cultures of N. tabacum, the nicotine contents of polymers were determined by gas chromatography and the adsorption yield of polymers were determined.

KEY FINDINGS

Cell cultures of N. tabacum accumulated nicotine alkaloid intracellularly in varying levels, 6.8-14.9 mg/l fresh weight. MIPs were able to uptake 50-70% of released nicotine in suspension cultures of N. tabacum, whereas XAD-2 recovered only 30-40%. The total levels of accumulated nicotine were enhanced up to 20 mg/l by simultaneous use of Tween 80 and MIPs.

CONCLUSIONS

The findings indicate the potential use of MIPs to uptake nicotine from suspension cultures of N. tabacum, and increase productivity of secondary metabolites in plant cell cultures.

Determination of hair nicotine by gas chromatography-mass spectrometry

Hair nicotine is a known biomarker for monitoring long-term environmental tobacco smoke (ETS) exposure and smoking status. In general, hair nicotine assay involves alkaline digestion, extraction and instrumental analysis. The gas chromatography-mass spectrometry (GC-MS) assay currently developed has shown to be of high throughput with average approximately 100 hair samples being extracted and analyzed per day. This was achieved through simplified extraction procedure and shortened GC analysis time. The extraction was improved by using small volume (0.4 mL) of organic solvent that does not require further evaporation and salting steps prior to GC-MS analysis. Furthermore, the amount of hair utilized in the extraction was very little (5 mg) while the sensitivity and selectivity of the assay is equal, if not better than other established methods. The linearity of the assay (r(2)>0.995), limit of quantitation (0.04 ng/mg hair), within- and between-assays accuracies and precisions (<11.4%) and mean recovery (92.6%) were within the acceptable range.