Meconium nicotine and metabolites by liquid chromatography-tandem mass spectrometry: differentiation of passive and nonexposure and correlation with neonatal outcome measures

Recent Developments in the Determination of Biomarkers of Tobacco Smoke Exposure in Biological Specimens: A Review

Environmental tobacco smoke exposure (ETS) and smoking have been described as the most prevalent factors in the development of certain diseases worldwide. According to the World Health Organization, more than 8 million people die every year due to exposure to tobacco, around 7 million due to direct ETS and the remaining due to exposure to second-hand smoke. Both active and second-hand exposure can be measured and controlled using specific biomarkers of tobacco and its derivatives, allowing the development of more efficient public health policies. Exposure to these compounds can be measured using different methods (involving for instance liquid- or gas-chromatographic procedures) in a wide range of biological specimens to estimate the type and degree of tobacco exposure. In recent years, a lot of research has been carried out using different extraction methods and different analytical equipment; this way, liquid-liquid extraction, solid-phase extraction or even miniaturized procedures have been used, followed by chromatographic analysis coupled mainly to mass spectrometric detection. Through this type of methodologies, second-hand smokers can be distinguished from active smokers, and this is also valid for e-cigarettes and vapers, among others, using their specific biomarkers. This review will focus on recent developments in the determination of tobacco smoke biomarkers, including nicotine and other tobacco alkaloids, specific nitrosamines, polycyclic aromatic hydrocarbons, etc. The methods for their detection will be discussed in detail, as well as the potential use of threshold values to distinguish between types of exposure.

Assessment of Tobacco Exposure During Pregnancy by Meconium Analysis and Maternal Interview

Smoking during pregnancy can have serious obstetric and fetal complications. Therefore, it is essential to identify in utero exposure to tobacco, being meconium the matrix of choice for this purpose. Meconium (n = 565) was analyzed for nicotine, cotinine and hydroxycotinine by LC-MS-MS. Then, tobacco meconium results were compared with smoking habits during pregnancy and neonatal outcomes measures (birth weight, length, head circumference, gestational age and Apgar scores). Although meconium analysis increased identification of in-utero exposure to tobacco (17.7% meconium positive specimens vs 13.5% mothers admitting tobacco use during pregnancy), there was a statistically significant relationship between meconium results and interview answers (P < 0.001). Birth weight was significantly lower for newborns with meconium positive results in males (P = 0.023) and females (P = 0.001), while for length significance was only observed in females (P = 0.001); however, when excluding meconium specimens positive for other drugs, a statistically significant difference was only found for female weight (P = 0.045). Meconium analysis proved to be more reliable for tobacco prenatal exposure detection than maternal interview. In addition, positive meconium results increased the probability for low birth weight, especially in females.

Monitoring of prenatal exposure to organic and inorganic contaminants using meconium from an Eastern Canada cohort

Evaluating in utero exposure to inorganic and multiclass organic contaminants is critical to better evaluate potential harmful effects on prenatal and postnatal development. The analysis of meconium, the first bowel discharge of the newborn, has been proposed as a non-invasive way to assess cumulative prenatal exposure. The aim of this study was to implement an analytical method for quantifying 72 targeted organic compounds, including pesticides, pharmaceutical compounds and daily life xenobiotics, in meconium in addition to selected elements (17 elements). We report initial monitoring results based on the analysis of 396 meconium samples from an Eastern Canada cohort (Quebec, Canada). Element contents in meconium were analysed by mass spectrometry after digestion in nitric acid and peroxide. Targeted organic compounds were extracted and purified from meconium samples by a solid-liquid extraction followed by a dispersive-SPE purification before tandem mass spectrometry analysis. Concentrations of targeted elements were within the range of concentration reported in European and US studies but were lower than concentrations found in a developing country cohort (i.e., Pb, Cd). Out of the 72 targeted organic compounds, 31 were detected at least once and 30 were quantified. Compounds with the highest frequency of detection were caffeine, detected in all samples (from 2.80 to 6186 ng g-1), followed by acetaminophen detected in 53% of the samples (up to ~402 µg g-1) and methyl paraben detected in 20% of the samples (up to ~10 µg g-1). Pesticides were detected in low frequencies (< 2%) and low concentration (< 35 ng g-1). Results show that meconium can be used to monitor prenatal exposure of foetus to a wide array of inorganic and organic contaminants.

Assessment of tobacco, alcohol and cannabinoid metabolites in 645 meconium samples of newborns compared to maternal self-reports

Prenatal psychoactive substance exposure has significant impact on neonatal health and child development and the development of reliable biomarkers is critical. Meconium presents several advantages for detecting prenatal exposure to psychoactive substances, as it is easy to collect and provides a broad time frame of exposure (third trimester). The aim of our study was to compare the prevalence of alcohol, tobacco and/or cannabis use during the third trimester of pregnancy (using maternal self-reports) with the results of meconium testing of their metabolites in newborns (cotinine, ethyl-glucuronide (EtG) and cannabinoid metabolites). Among all deliveries (993) that occurred in all maternities in Rouen (Normandy) during a defined time period (5 consecutive weeks in August, 2010 and August, 2011), 724 mothers were included and 645 meconium samples were collected. Maternal self-reports, using the Addiction Severity Index (5th edition), and meconium samples were collected within 72 h of delivery. Cotinine detection appears highly correlated to maternal self-reports (Kappa value: 0.79; [95%CI: 0.73-0.85]). Moreover, detection in meconium seems more accurate in the prediction of neonatal consequences of prenatal tobacco exposure as compared to maternal self-reports. In contrast, we have found a lower concordance between maternal self-reports and meconium testing for EtG and cannabinoid metabolites (Kappa value: 0.13; [95%CI: 0.04-0.22] and: 0.30; [95%CI: -0.03-0.63], respectively); however the total number of EtG- and cannabinoid-positive meconium samples was small. Interestingly, meconium samples with the highest levels of EtG mainly corresponded to negative maternal self-reports. Fetal exposure to alcohol, tobacco or cannabis may also considerably differ as displayed in our pairs of dizygotic twins. Finally, a polyconsumption of these psychoactive substances was not frequently observed according to meconium testing. In conclusion, cotinine detection appears as a valuable meconium biomarker. EtG measurement in meconium samples seems interesting if there is any risk of high fetal exposure, whereas assessment of prenatal cannabis exposure, using meconium testing, needs to be improved.

Medical swab touch spray-mass spectrometry for newborn screening of nicotine and cotinine in meconium

Newborn screening is one of public health concerns designed to screen infants shortly after birth. Prenatal exposure to tobacco smoke such as nicotine has been reported to affect babies. Levels of nicotine and cotinine in meconium were widely used to evaluate the tobacco exposure of foetuses during pregnancy in a polluted environment. In this study, medical swabs were applied by using touch spray-mass spectrometry (TS-MS) to collect meconium from newborn infants for detection of nicotine and cotinine. Parameters such as choice of spray solvents, solvent volume and collision energy for screening of nicotine and cotinine were optimized. The limits of detection, reproducibility and matrix effect for analysis of meconium were also investigated. In this study, the levels of nicotine and cotinine in 54 puerpera volunteers were screened by TS-MS and were validated by using traditional liquid chromatography-mass spectrometry. These results showed that medical swab TS-MS would be useful for newborn screening of nicotine and cotinine in meconium with high reproducibility, speed, sensitivity and specificity. The use of disposable medical swabs involves no sample preparation and no chromatographic separation, significantly reducing the cost and time required for screening a large number of clinical sample. Copyright © 2016 John Wiley & Sons, Ltd.

Determination of nicotine and cotinine in meconium from Greek neonates and correlation with birth weight and gestational age at birth

Tobacco exposure during pregnancy is a major factor of morbidity and mortality for both the pregnant woman and the fetus. Several studies in the past have detected and quantified tobacco smoke biomarkers in infant meconium samples. Aim of this study was to measure prenatal exposure to tobacco smoke by detecting nicotine and cotinine in meconium and to try to evaluate the extent of exposure to smoke through passive smoking as well as the relationship between tobacco biomarker meconium concentrations and neonatal outcomes. Tobacco smoke biomarkers nicotine and cotinine were detected and quantitated in meconium from tobacco exposed and non-exposed Greek neonates using liquid chromatography-tandem mass spectrometry. The study included 45 neonates from active, passive and non-smoking women during pregnancy. The results showed significant values of nicotine and cotinine concentration in neonates from both active and passive smokers which reached 125 ng g(-1) for nicotine and 98.5 ng g(-1) for cotinine and varied according to the type and level of exposure. In general nicotine and cotinine concentrations correlated with the degree of active smoking by the mother. Similarly, nicotine and cotinine were measured in the meconium of infants of passive smokers at concentrations comparable to those of infants whose mothers were moderate smokers. Our findings show that exposure of the fetus to tobacco biomarkers can be substantial even in passive maternal smoking and there is a statistically significant negative correlation between nicotine or cotinine concentrations in meconium and birth weight or gestational age at birth.

Transgenerational exposure to environmental tobacco smoke

Traditionally, nicotine from second hand smoke (SHS), active or passive, has been considered the most prevalent substance of abuse used during pregnancy in industrialized countries. Exposure to environmental tobacco smoke (ETS) is associated with a variety of health effects, including lung cancer and cardiovascular diseases. Tobacco is also a major burden to people who do not smoke. As developing individuals, newborns and children are particularly vulnerable to the negative effects of SHS. In particular, prenatal ETS has adverse consequences during the entire childhood causing an increased risk of abortion, low birth weight, prematurity and/or nicotine withdrawal syndrome. Over the last years, a decreasing trend in smoking habits during pregnancy has occurred, along with the implementation of laws requiring smoke free public and working places. The decrease in the incidence of prenatal tobacco exposure has usually been assessed using maternal questionnaires. In order to diminish bias in self-reporting, objective biomarkers have been developed to evaluate this exposure. The measurement of nicotine and its main metabolite, cotinine, in non-conventional matrices such as cord blood, breast milk, hair or meconium can be used as a non-invasive measurement of prenatal SMS in newborns. The aim of this review is to highlight the prevalence of ETS (prenatal and postnatal) using biomarkers in non-conventional matrices before and after the implementation of smoke free policies and health effects related to this exposure during foetal and/or postnatal life.

Prenatal tobacco exposure, biomarkers for tobacco in meconium, and neonatal growth outcomes

OBJECTIVE

To assess relationships between marker concentrations of tobacco in meconium and weekly self-reported maternal cigarette consumption, and prediction of neonatal growth outcomes.

STUDY DESIGN

Pregnant mothers (n = 119) from a longitudinal maternal smoking and infant neurobehavioral study (Behavior and Mood in Babies and Mothers [BAM BAM]) provided daily tobacco smoking histories. Nicotine, cotinine, and trans-3'-hydroxycotinine concentrations were quantified in 111 neonatal meconium specimens by liquid chromatography-tandem mass spectrometry.

RESULTS

Median self-reported third trimester smoking was 5.9 cigarettes per day among smokers. Meconium samples from infants born to non-smokers (n = 42) were negative for tobacco markers, while specimens from self-reported smokers (n = 41) were positive for (median, range) nicotine (50.1 ng/g, 3.9-294), cotinine (73.9 ng/g, 6.4-329), and trans-3'-hydroxycotinine (124.5 ng/g, 10.2-478). Quitters (n = 28) self-reported stopping smoking at gestational weeks 2-39. Four meconium specimens from quitters were positive for tobacco biomarkers. Reduced birth weight, length, and head circumference significantly correlated with presence of meconium markers but not with individual or total marker concentrations. Among quitters and smokers, reduced infant birth weight, head circumference, and gestational age correlated with total and average daily cigarette consumption in the second and third trimesters.

CONCLUSION

Smoking cessation or reduction during pregnancy improved neonatal outcomes. The window of detection for tobacco in meconium appears to be the third trimester; however, low exposure in this trimester failed to be detected. These results will aid physicians in educating women who are pregnant or thinking about becoming pregnant on the negative consequences of smoking during pregnancy. In addition, infants at risk can be identified at birth to assist early intervention efforts.

Nicotine and metabolites in paired umbilical cord tissue and meconium specimens

Umbilical cord tissue was studied as a means of detecting prenatal exposure to nicotine. This was accomplished by comparing the presence and concentration of nicotine as well as nicotine metabolites in both umbilical cord tissue and paired meconium samples with maternal smoking histories obtained by self-report. Nicotine and metabolites (cotinine, 3-hydroxycotinine, nornicotine, and anabasine) were detected and quantitated using liquid chromatography-tandem mass spectroscopy. Between June and September 2009, 19 women with a tobacco exposure history (either first- or second-hand tobacco smoke exposure during pregnancy) were consented for the study. A questionnaire was completed to document nicotine exposure during each trimester of pregnancy. All infants were delivered at term (38 weeks or greater) and paired umbilical cord tissue (10-cm segment or greater) and meconium were obtained. Nicotine and 3-hydroxycotinine were most prominent in meconium, whereas cotinine and 3-hydroxycotinine were most prominent in the umbilical cord. Concentrations of all three analytes were generally higher in meconium. Nornicotine was detected only in meconium, at very low concentrations, and anabasine was not detected in either specimen. All analyte concentrations were lowest when the mother stated she quit smoking early in pregnancy or had only second-hand exposure, and detection was poor if exposure was limited to the first or second trimesters. Although different nicotine and metabolite patterns exist in meconium versus umbilical cord tissue, this work indicates that either specimen can be used to detect third-trimester fetal nicotine exposure.

Measurement of nicotine, cotinine and trans-3'-hydroxycotinine in meconium by liquid chromatography-tandem mass spectrometry

Nicotine (NIC), cotinine (COT) and trans-3'-hydroxycotinine (OHCOT) are the most prevalent and abundant tobacco biomarkers in meconium. We have developed and validated an accurate and precise method for the measurement of these analytes in meconium in which potassium hydroxide is used to digest the meconium sample, followed by solid phase extraction from the liquified sample. The precision of OHCOT, COT and NIC measurements (intra-day and inter-day) were 4.8-10.6%, 3.4-11.6% and 9.3-15.8%, respectively. Evaluation of accuracy indicated bias of -4.0, 2.0 and 0.8% for OHCOT at concentrations of 0.5, 2.5 and 7.5 ng/g. The accuracy estimates for COT at concentrations of 0.5, 2.5 and 7.5 ng/g are 4.0, 4.0 and 5.7%, respectively. For NIC at 2, 10 and 30 ng/g the accuracy was calculated to be 3.0, 5.0 and 5.1%, respectively. The linear range of standard solutions was 0.125-37.5 ng/mL for OHCOT and COT, and 0.75-150 ng/mL for NIC. This method was applied to the analysis of 374 meconium samples from infants of both smoking and nonsmoking mothers. Positive correlations with r(2)≥0.63 were observed between NIC and COT, COT and OHCOT, NIC and OHCOT, and NIC and (OHCOT+COT) in these samples.

A prospective cohort study of biomarkers of prenatal tobacco smoke exposure: the correlation between serum and meconium and their association with infant birth weight

BACKGROUND

The evaluation of infant meconium as a cumulative matrix of prenatal toxicant exposure requires comparison to established biomarkers of prenatal exposure.

METHODS

We calculated the frequency of detection and concentration of tobacco smoke metabolites measured in meconium (nicotine, cotinine, and trans-3'-hydroxycotinine concentrations) and three serial serum cotinine concentrations taken during the latter two-thirds of pregnancy among 337 mother-infant dyads. We estimated the duration and intensity of prenatal tobacco smoke exposure using serial serum cotinine concentrations and calculated geometric mean meconium tobacco smoke metabolite concentrations according to prenatal exposure. We also compared the estimated associations between these prenatal biomarkers and infant birth weight using linear regression.

RESULTS

We detected nicotine (80%), cotinine (69%), and trans-3'-hydroxycotinine (57%) in most meconium samples. Meconium tobacco smoke metabolite concentrations were positively associated with serum cotinine concentrations and increased with the number of serum cotinine measurements consistent with secondhand or active tobacco smoke exposure. Like serum cotinine, meconium tobacco smoke metabolites were inversely associated with birth weight.

CONCLUSIONS

Meconium is a useful biological matrix for measuring prenatal tobacco smoke exposure and could be used in epidemiological studies that enroll women and infants at birth. Meconium holds promise as a biological matrix for measuring the intensity and duration of environmental toxicant exposure and future studies should validate the utility of meconium using other environmental toxicants.

Nicotine and metabolites in meconium as evidence of maternal cigarette smoking during pregnancy and predictors of neonatal growth deficits

INTRODUCTION

Many women continue tobacco use during pregnancy despite known adverse consequences on neonatal growth and development. Testing meconium, the first neonatal feces, for tobacco biomarkers offers objective evidence of prenatal tobacco exposure. However, relationships between the amount, frequency, and timing of cigarette smoking during gestation and tobacco biomarker meconium concentrations and neonatal outcomes are unclear.

METHODS

Eighty-seven pregnant women provided detailed self-reports of daily tobacco consumption throughout pregnancy. Nicotine, cotinine, and trans-3'-hydroxycotinine were quantified in neonatal meconium by liquid chromatography-tandem mass spectrometry.

RESULTS

Among nonsmokers, all meconium specimens were negative, whereas nearly all meconium specimens were positive if the mother self-reported tobacco use into the third trimester. Tobacco biomarker concentrations were significantly albeit weakly correlated with mean cigarettes per day in the third trimester. Reduced birth weight, gestational age, or head circumference were observed if meconium contained one or more tobacco biomarkers, but deficits did not correlate with biomarker concentrations.

CONCLUSION

While previously thought to reflect second and third trimester drug exposure, meconium appears to reliably identify only third trimester drug use. While a 10 ng/g nicotine, cotinine, or trans-3'-hydroxycotinine cutoff in meconium was previously proposed to differentiate tobacco-exposed from nonexposed or passively exposed neonates, improved maternal self-reporting techniques in this cohort suggest that a lower cutoff, equivalent to the analytic limits of quantification, is more appropriate.

Identification of prenatal amphetamines exposure by maternal interview and meconium toxicology in the Infant Development, Environment and Lifestyle (IDEAL) study

The Infant Development Environment and Lifestyle study is investigating the effects of prenatal methamphetamine (MAMP) exposure on infant and child development; potential concurrent exposure to cannabis and tobacco also are evaluated. Maternal self-reported drug use and/or meconium toxicology results defined drug exposure status. It is unclear how the frequency, duration, and magnitude of maternal MAMP exposure affect qualitative and quantitative meconium results. Interviews regarding maternal drug use were collected shortly after birth; meconium specimens were screened for amphetamines, cannabis, and cotinine by immunoassay and confirmed by gas chromatography mass spectrometry. The majority of MAMP- and cannabis-exposed infants were identified by maternal interview alone. Meconium tests were more likely to be positive if the mother reported MAMP and cannabis use, particularly in the third trimester. Less than half of immunoassay-positive amphetamines (31.0%) and cannabis (17.9%) meconium results were confirmed by gas chromatography mass spectrometry. Tobacco exposure was equally detected by immunoassay cotinine screening and maternal report. Meconium concentrations did not correlate with maternal self-report status or trimester of use or frequency or route of MAMP use. Maternal self-report was more sensitive than meconium testing for identifying MAMP and cannabis-exposed neonates; however, the timing of drug exposure may influence meconium toxicology results. Most women stopped MAMP and cannabis use before the third trimester. In the first trimester, meconium has not yet formed, and based on our recent results for opiates and cocaine, drug use in the second trimester appears to be poorly reflected in meconium. Low confirmation rates in meconium reinforce the need for confirmatory testing following positive screening results and additional research to identify alternative biomarkers.

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.

Development and validation of a liquid chromatography mass spectrometry assay for the simultaneous quantification of methadone, cocaine, opiates and metabolites in human umbilical cord

A liquid chromatography mass spectrometric selected reaction monitoring mode (SRM) method for methadone, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), cocaine, benzoylecgonine (BE), 6-acetylmorphine, morphine and codeine quantification in human umbilical cord was developed and fully validated. Analytes were extracted from homogenized tissue (1g) by solid phase extraction. Linearity was 2.5-500ng/g, except for methadone (10-2000ng/g). Method imprecision was <12.7%CV with analytical recovery 85.9-112.7%, extraction efficiency >59.2%, matrix effect 4.5-39.5%, process efficiency 48.6-92.6% and stability >84.6%. Analysis of an umbilical cord following controlled methadone administration and illicit drug use contained in ng/g, 40.3 morphine, 3.6 codeine, 442 BE, 186 methadone and 45.9 EDDP.

A liquid chromatography tandem mass spectrometry method for the simultaneous quantification of 20 drugs of abuse and metabolites in human meconium

A method for the simultaneous quantification of 20 cocaine, amphetamine, opiate, and nicotine analytes in meconium, the first neonatal feces, by liquid chromatography tandem mass spectrometry was developed and validated. Specimen preparation included methanol homogenization and solid phase extraction. Two injections were required to achieve sufficient sensitivity and linear dynamic range. Linearity ranged from 0.5-25 up to 500 ng/g (250 ng/g p-hydroxymethamphetamine), and correlation coefficients were >0.996. Imprecision was <10.0% CV, analytical recovery 85.5-123.1%, and extraction efficiencies >46.7% at three concentrations across the linear range. Despite significant matrix effects of -305.7-40.7%, effects were similar for native and deuterated analytes. No carryover, endogenous or exogenous interferences were observed, with analyte stability at room temperature, 4 degrees C, and -20 degrees C and on the autosampler >70%, except for 6-acetylmorphine, hydrocodone, oxycodone, and morphine. Method applicability was demonstrated by analyzing meconium from drug-exposed neonates.