Tobacco Samples Research Articles

Preparation and application of molecularly imprinted polymer solid-phase microextraction fiber for the selective analysis of auxins in tobacco.

As signal molecules, auxins play an important role in mediating plant growth. Due to serious interfering substances in plants, it is difficult to accurately detect auxins with traditional solid-phase extraction methods. To improve the selectivity of sample pretreatment, a novel molecularly imprinted polymer -coated solid-phase microextraction fiber, which could be coupled directly to high-performance liquid chromatography, was prepared with indole acetic acid as template molecule for the selective extraction of auxins. The factors influencing the polymer formation, such as polymerization solvent, cross-linker, and polymerization time, were investigated in detail to enhance the performance of indole acetic acid-molecularly imprinted polymer coating. The morphological and chemical stability of this molecularly imprinted polymer-coated fiber was characterized by scanning electron microscopy, infrared spectrometry, and thermal analysis. The extraction capacity of the molecularly imprinted polymer-coated solid-phase microextraction fiber was evaluated for the selective extraction of indole acetic acid and indole-3-pyruvic acid followed by high-performance liquid chromatography analysis. The linear range for indole acetic acid and indole-3-pyruvic acid was 1-100µg/L and their detection limit was 0.5µg/L. The method was applied to the simultaneous determination of two auxins in two kinds of tobacco (Nicotiana tabacum L and Nicotiana rustica L) samples, with recoveries range from 82.1 to 120.6%.

Pepper yellow leaf curl Aceh virus: a novel bipartite begomovirus isolated from chili pepper, tomato, and tobacco plants in Indonesia.

During 2017, leaf samples of chili pepper (Capsicum annuum), tomato (Solanum lycopersicum), and tobacco (Nicotiana tabacum) plants exhibiting yellowing and curling symptoms were collected from Aceh province, Indonesia. These samples were used to isolate and sequence viral genomic DNA. Six isolates with complete DNA-A and DNA-B sequences of begomovirus were obtained, all of which showed >99% sequence identity to the others. DNA-A sequences shared the highest nucleotide sequence identity (89.3%-89.7%) with monopartite pepper yellow leaf curl Indonesia virus 2 (PepYLCIV2) and the second-highest sequence identity (87.3%-87.4%) with bipartite pepper yellow leaf curl Indonesia virus (PepYLCIV). The DNA-B sequences shared the highest nucleotide sequence identity (95%-97.5%) with PepYLCIV. Results of recombination analysis indicated that the novel begomovirus was a recombinant. In accordance with the guidelines for begomovirus species demarcation, these isolates should be assigned to a new species, and we have proposed the name ''pepper yellow leaf curl Aceh virus'' (PepYLCAV) for this virus.

Ultra trace level square wave anodic stripping voltammetric sensing of mercury(II) ions in environmental samples using a Schiff base-modified carbon paste electrode

ABSTRACT In this approach, a new carbon paste electrode modified with N,N′-bis(5-bromo-2-hydroxybenzylidene)-2,2-dimethylpropane-1,3-diamine Schiff base ligand (L) was synthesised for selective and effective determination of Hg2+ ions in aqueous environmental samples using cyclic and square wave anodic stripping voltammetric methods. First, the selective detection of mercury ion was confirmed by evaluating the stability constants of metal complexes formed between the Schiff base ligand (L) and some desired cations by conductometric measurements. Afterwards, by preparing an effective carbon paste electrode modified with L, the experimental and instrumental parameters affecting the performance of modified electrode were investigated. Square wave anodic stripping voltammograms were obtained after applying an accumulation potential −0.5 V and accumulation time 150 s in Britton–Robinson buffer solution at pH 2.0. The optimal square wave parameters found are pulse amplitude 75 mV, frequency 50 Hz and step potential 6 mV. The procedure exhibited linear range from 0.4 to 120 μg L−1 Hg2+ with a limit of detection of 0.042 μg L−1. The proposed electrode was proved to be highly selective in the presence of various cations and anions and was successfully used for determination of mercury in tobacco and several water samples.

Similarity measure method based on spectra subspace and locally linear embedding algorithm

Due to the high dimensionality, redundancy, noise and nonlinearity of the near infrared (NIR) spectra data result the difficulty of the similarity measure. This paper presented a similarity measure method SSLLE based on the spectra subspace and locally linear embedding (LLE) algorithm. Firstly, we divided the high dimensional spectra data into several subspaces according to the absorption band of the major chemical compositions, which effectively avoids the influence of irrelevant features and noise and reduces the dimension and computation complexity of the LLE. Then, we modified the LLE algorithm by introducing the geodesic distance instead of Euclidean distance, which solves the measure problem of the Euclidean distance in high dimensional space. In order to make the sample more evenly distributed, the method of distance calculation in LLE was also modified. For each spectra subspace, the distance matrix was calculated according to the embedding that was mapped from the high dimensional space by using the modified LLE. Subsequently, the spectral similarity matrix of the sample set was integrated by adding all of the individual distance matrices of each subspace so that the sample with the highest similarity can be found.In order to investigate the effectiveness of the algorithm, the spectral projection of the samples was analyzed first, the results showed that the SSLLE distinguished the tobacco samples from different areas significantly better than the methods of principal component analysis (PCA) and LLE. Secondly, we compared the results of searching the most spectrally similar sample with the target tobacco, it showed that the SSLLE had the minimum differences in the chemical composition, and the highest consistency with the recommendation of the experts than that of PCA and LLE algorithm. It also had good robustness and precision.

From smart drugs to smartphone: A colorimetric spot test for the analysis of the synthetic cannabinoid AB-001

The use of synthetic cannabinoids is an emerging problem in contemporary society, and the detection techniques currently used do not meet the requirements of a drug test. We report herein an inexpensive, in situ method for the detection of the synthetic cannabinoid AB-001 in herbal samples. The method exploits a colorimetric kit consisting in a 96 plate well containing a bench stable modified Ehrlich reagent adsorbed on silica. The colour derived by the interaction of AB-001 with the detection matrix is read on a RGB (Red, Green, and Blue) base by using the camera of a smartphone, thus making the method accessible to everyone.A calibration curve of the analyte in the range 1–200 μg was realized, with a MQL (method quantitation limit) of 1 μg and positive recovery tests from samples of tobacco and damiana spiked with different amounts of AB-001. The method presents selectivity for AB-001 with respect to other indole-based cannabinoids (e.g. JWH-018, JWH-302, whose response is ca 5% of the one produced by the same concentration of AB-001) and other common drugs (e.g. acetaminophen, ascorbic acid, bromazepam, fluoxetine), these last not interfering up to a 100:1 drug:AB-001 ratio.This new colorimetric approach would be considered a category C screening test, and therefore recommended as part of a comprehensive analytical scheme for the identification of AB-001.

Analysis of chemosensory markers in cigarette smoke from different tobacco varieties by GC×GC-TOFMS and chemometrics

Commercial cigarettes are made from a blend of different tobacco varieties, which in turn are the results of different agronomic practices and post-harvest curing processes. The highly complex mixture of smoke compounds reflects each tobacco variety and the levels of sensory-relevant markers. Therefore, the aim of this work was to identify potential relevant chemosensory markers in the mainstream smoke of four main types of commercial tobaccos and establish any possible relationship between them and the tobacco growing/curing practices. The tobacco samples were segregated into four segments: (1) three curing stages of flue-cured Virginia, (2) three curing stages of air-cured Burley, (3) three geo-regions of sun-cured Oriental and (4) three different process applied to tobacco. One hundred and twenty cigarettes (10 batches per flavour category) were produced and smoked under standard machine-smoking protocols. The mainstream smoke samples collected were extracted and analysed by GC × GC TOFMS. The processed data was analysed by partial least square discriminant analysis (PLS-DA) and the selectivity ratio was used to identify key chemosensory markers responsible for the four segments. All models had sensitivity and specificity equal to unity. Flue-cured Virginia (193 markers) and air-cured Burley (184 markers) showed a similar trend for O-heterocycles markers in the lighter leaf colours and N-heterocycles in the darker leaf colours post-processing, but they had compounds of different flavour descriptions, e. g. sweet and nutty. The three geo-regions of sun-cured Oriental (290 markers) also presented O-heterocycles markers in correlation with leaf sugar contents in addition of sucrose esters markers. The three unusually processed tobacco generated many chemical markers (436 markers), some derived from the so-called Cavendish fermentation process with sweet, spicy and peppery notes, whereas the dark fermented air-cured tobacco presented similar descriptors as air-cured Burley. In addition, some polycyclic aromatic hydrocarbons (PAH) were detected as markers from the fire-curing process. The PLS-DA with selectivity ratio evidenced total of 1098 chemosensory markers in cigarette smoke, in which 173 were tentatively identified.

A liquid chromatography-tandem mass spectrometry method to simultaneously determinate dichlorvos and phoxim in tobacco.

A simple pretreatment method with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated to simultaneously determine dichlorvos and phoxim in tobacco and soil matrices. Satisfactory linearity (R2 ≥ 0.9991) of the method was obtained for both analytes. The limits of detection and limits of quantification for dichlorvos and phoxim in three matrices were 0.0015-0.006 and 0.005-0.02 mg/kg, respectively. Average recoveries were 78.24-92.21% for dichlorvos and 76.62-100.51% for phoxim in soil, green tobacco leaves and cured tobacco leaves. The intra- and inter-day relative standard deviations were <6%. The established method was successfully applied for the residual analysis of dichlorvos and phoxim in real soil and tobacco samples. The results indicated that the established method could be used to detect trace amounts of dichlorvos and phoxim in tobacco. The data could also help the Chinese government establish maximum residue limits of dichlorvos and phoxim on tobacco and establish proper and safe use of dichlorvos and phoxim on tobacco plants in China.

GC-MS Analysis and Cytotoxicity Evaluation of Shammah (Smokeless Tobacco) Samples of Jazan Region of Saudi Arabia as Promoter of Cancer Cell Proliferation

Shammah is a locally manufactured form of smokeless tobacco (ST) which is traditionally used in Middle Eastern countries including Saudi Arabia, Sudan, and Yemen. Presence of a high concentration of nicotine, in addition to various other toxic and carcinogenic constituents, makes it a serious human health threat. It is an admixture containing powdered tobacco, along with several additives, such as lime, ash, black pepper, volatile oils, and flavoring agents. This study was conducted to investigate the constituents of eight different samples of widely used shammah varieties in the Jazan region of Saudi Arabia using GC-MS and to evaluate their cytotoxic effect against three cancer cell lines representing most of the top malignancies in the region including MCF-7, A2780, and HT29 cancer cells, in addition to MRC5 cells (normal human fetal lung fibroblast) using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. GC-MS analysis showed the presence of nicotine or 3-(1-methyl-2-pyrrolidinyl)pyridine (2.1–91.9% of total constituents detected) in all ST samples, whereas its derivative (1s,2s)-nicotine-N-oxide (0.23–1.62%) was detected in four samples. In addition, several known carcinogenic constituents were also identified, and their carcinogenicity was confirmed by MTT results, in which, all the eight samples promoted the growth of MCF7, A2780, and HT29 cancer cells. The cytotoxic effects of samples against the normal cells MRC5 was proportional to the number of components detected by GC-MS. The ingestion of these constituents through saliva of shammah consumers could be the reason for many cancers including breast, ovary, and colon cancers. These results support the urgent local and international call to educate the users regarding the deleterious effects of shammah to avoid its use.

Quantitative analysis of cembranoids in tobacco leaf by using heart‐cutting two‐dimensional liquid chromatography

AbstractA novel heart‐cutting two dimensional liquid chromatography method had been developed to analyze two cembranoids tobacco leaf. The reversed phase liquid chromatography column was employed for separation. Then target elution was cut to the trap column by on‐line dilution from the compensate pump. After switching the six‐port valve, the analytes were eluted to the second dimension. The two cembranoids were determined qualitatively and quantitatively by UV detection. The new method was fairly simplified sample pretreatment. When the approach was engaged to real samples, it showed high sensitivity without matrix interference. Limits of detection for two cembranoids were 0.0083 and 0.0060 mg/g, and limits of quantification were 0.027 and 0.020 mg/g, respectively. The intra‐day and inter‐day relative standard deviation of the cembranoids were within 1.8%. Spiked recoveries were ranged from 98.4 to 109.5%. Therefore, the two dimensional liquid chromatography method was successfully utilized to cembranoids detection in a wide range of the tobacco samples.

Quality evaluation of flue-cured tobacco by near infrared spectroscopy and spectral similarity method.

Herein we propose near infrared (NIR) spectroscopy as a rapid method of evaluating the quality of agricultural products. Unlike existing quantitative or qualitative models, quality similarity is characterised using spectral similarity. Key factors of the spectral similarity method were investigated, including variable selection, pre-processing and similarity measures. Sophisticated techniques were developed to ensure the reliability of similarity algorithm. The proposed method was tested by quality similarity of flue-cured tobacco samples. The results demonstrated that the quality-related factors between the target and the similar samples (determined by spectral similarity), showed high similarities. This new method has the potential to characterise product quality effectively and could be a useful new alternative to the widely used PLS models.

Use of autoclave extraction-supercritical fluid chromatography/tandem mass spectrometry to analyze 4-(methylintrosamino)-1-(3-pyridyl)-1-butanone and N’-nitrosonornicotine in tobacco

4-(methylintrosamino)-1-(3-pyridyl)-1-butanone (NNK) and N’-nitrosonornicotine (NNN) are the most prevalent and toxic tobacco specific nitrosamines (TSNAs). Due to their carcinogenicity, knowledge of the composition of NNK and NNN in tobacco is necessary. Herein, a sensitive and rapid method, which employs autoclave extraction-supercritical fluid chromatography/tandem mass spectrometry (SFC-MS/MS), has been developed for the analysis of NNK and NNN in tobacco. Both water-soluble and matrix-bound NNK and NNN were extracted with 100 mM ammonium acetate in an autoclave (130 °C, 4 h), and the aqueous extract was subjected to solvent replacement prior to SFC-MS/MS analysis. NNK and NNN were effectively separated within 5 min by using supercritical CO2 as the main mobile phase coupled with a co-solvent of methanol. Excellent linearity was obtained with coefficients of determination (R2) greater than 0.9997 in the range of 1–160 ng/mL and 5–800 ng/mL for NNK and NNN, respectively. The recoveries were in the range of 92.5–110.0% at different spiked levels of real samples. 12 tobacco samples which include 3 typical tobacco varieties of burley, flue-cured, and oriental tobaccos had been analyzed, and the fraction of matrix-bound NNK was determined as well. In addition, a comparison between the proposed SFC-MS/MS method and a validated liquid chromatography tandem mass spectrometry (LC–MS/MS) internal standard method was conducted. Both techniques exhibit comparable analysis results, but peak splitting of NNN was observed by LC-MSMS due to the existence of E/Z isomers, while SFC-MS/MS offers great improvement through elution condition optimization, demonstrating the applicability of SFC-MS/MS as an alternative tool for NNK and NNN analysis.

Little cigars and cigarillos harbor diverse bacterial communities that differ between the tobacco and the wrapper.

Despite their potential importance with regard to infectious and chronic diseases among tobacco users, microbial constituents of tobacco products lack characterization. Specifically, to our knowledge, there are no data describing the bacterial diversity of little cigars or cigarillos. To address this knowledge gap, we tested four brands of little cigars and cigarillos. Tobacco and wrapper subsamples (n = 132) were separately subjected to DNA extraction, followed by PCR amplification of the V3V4 hypervariable region of the 16S rRNA gene, and sequencing using Illumina HiSeq. Sequences were analyzed using QIIME and Phyloseq implemented in R. We identified 2,681 operational taxonomic units across all products. Significant differences in alpha and beta diversity were observed between Swisher Sweets and Cheyenne products. Alpha and beta diversity was also significantly different between tobacco and wrapper subsamples within the same product. Beta diversity analyses of only tobacco samples identified no significant differences in the bacterial microbiota of different lots of the same products; however, the microbiota in the wrapper differed significantly across lots for all brands. Overall, Firmicutes were found to dominate in the wrapper, whereas Proteobacteria were most abundant in the tobacco. At the genus level, Bacillus and Lactobacillus dominated in the wrappers, and Staphylococcus and Pseudomonas dominated in the tobacco. Our findings suggest that the bacterial microbiota of little cigars and cigarillos is diverse and differs significantly between the tobacco and the wrapper, and across brands. Future work is necessary to evaluate the potential public health implications of these findings.

Near infrared spectroscopic analysis of total alkaloids as nicotine, total nitrogen and total ash in Cuban cigar tobacco

Three models using partial least squares regression of near infrared reflectance spectroscopy were developed for the first time to evaluate the concentration of total alkaloids as nicotine, total nitrogen and total ash in powdered samples of Cuban cigar tobacco. They had lower standard error of cross-validation (SECV) and standard error of prediction (SEP) than those using: (1) principal components regression; (2) multiple linear regression and (3) other partial least squares models previously published for this and other tobacco types. SECV values in mass fraction units were: 0.0010, 0.0011 and 0.0048, respectively. The coefficients of determination (R2) in calibration were: 0.99, 0.94 and 0.96, respectively. Standard error of prediction values were: 0.0011, 0.0012 and 0.0049, respectively. The r2 obtained when comparing the predicted values using the validation set with the reference data was nearly the same as in calibration. The equation for total alkaloids as nicotine was good for quantification, and for process control, development and applied research according to the quotients range/standard error of prediction and standard deviation/standard error of prediction, respectively. Equations for the other analytes were as good as the one for alkaloids, but suitable only for screening purposes. Joint F-tests on the regression coefficients from ordinary least squares and iterative reweighted least squares fittings among predicted and reference data indicated slopes and intercepts enclosing 1 and 0, respectively. The relative systematic errors between the near infrared spectroscopy predicted values and the reference methods are close to the same figures reported previously for traditional analytical procedures under intermediate precision and reproducibility conditions; hence, the models are suitable for this industrial context.

Modern technologies for utilizing tobacco wastes

The problem of utilization or recycling industrial tobacco wastes is an important problem for tobacco industry. Economically preferable way for utilizing industrial tobacco wastes (tobacco scrap) is production smokeless products and hookah blends as wastes are utilized without special treatment. Monitoring of humidity and fractional composition of cut tobacco taken from tobacco rod/cigarette spoilage (tobacco scrap) is carried. Its long-term storage leads to increasing scrap and dust quantity. Researches on utilizing tobacco scrap for sniff and hookah blend production, which are considered to be less harmful compared to cigarettes, were carried. Chemical composition of American type tobacco and scrap was defined. Nicotine content varies from 0.9 to 2.4% and carbohydrates content – from 5.6 to 9.6%. Experimental samples of hookah blend were produced and their organoleptic and taste evaluation were carried. It was found that utilization of tobacco scrap is economically efficient for hookah blend production, as quality of final product made of leaf tobacco and tobacco scrap is similar. Experimental samples of sniff tobacco were produced in order to discover possibility of utilization industrial tobacco scrap for manufacturing this product. Consumer’s properties of sniff tobacco were evaluated by 100 points tasting protocol. This technology for sniff tobacco production from tobacco scrap allows manufacturing product of good quality, decreasing technological operations, rejecting stages of tobacco selection and its cutting and as the result decreasing cost of final product. The results of the research on utilizing tobacco scrap for hookah blend and sniff tobacco production proves optimality of recycling the tobacco wastes.

TG-FTIR study of evolved gas in the decomposition of different types of tobacco. Effect of the addition of SBA-15

Pyrolysis and oxidation reactions involving four types of tobacco (a flue-cured Virginia, an air-cured Burley, a fire-cured Kentucky, and Oriental) and a tobacco reference (3R4F), which is a US blended tobacco of burley, virginia and oriental, are studied in a thermogravimetric analyser coupled to a Fourier-transform infrared (TG-FTIR) spectrometer, under inert and oxidising atmospheres. We also assess the effect of the addition of SBA-15 on the thermal degradation of tobacco in both atmospheres. All tobacco samples exhibit similar decomposition patterns resulting from the pyrolysis of their components, mainly hemicellulose, cellulose and lignin. Virginia type tobacco undergoes a marked volatilisation/decomposition process at low temperatures (125–250 °C). Oriental and Burley type tobaccos, on the other hand, undergo this same process at high temperatures. 3R4F reference tobacco exhibits the largest peak intensity for the decomposition of hemicellulose, pectin and cellulose. IR data allow a better interpretation of the reactions as they occur. The presence of catalyst produces a decrease in the evolution of CO at high temperatures. More residue is obtained in the presence of catalyst, and it is also less reactive. Under oxidising conditions, the catalyst produces marked differences in the oxidation reactions of the residue resulting from the decomposition of hemicellulose, pectin and cellulose, by limiting the evolution of methane and inhibiting CO formation reactions at high temperature.

Comparative study of antimony exposition by cigarettes and alternatives of tobacco consumption

A comparative study of Sb(III) exposition is presented. The determination of trace amounts of Sb(III) present in tobacco samples (tobacco of conventional cigarettes, refill solutions for e-cigarettes, snuff used in water pipe, snus and dry rapé) has been realized by solid surface fluorescence using alizarin as fluorogenic reagent (λem = 450 nm, λexc = 363 nm). In a first step, a chemisorption on filter paper was carried out with the bile salt sodium cholate (pH 10.2). In these conditions, the metal was selectively retained on the solid support preventing the spectral interferences of the complex matrix. The calibration graphs resulted linear in the range of 0.24 to 304.4 μg L−1 with detection limit of 0.08 μg L−1 (S/N = 3.3). Results were truenessed by ETAAS with adequate agreement. The results will be used in prevention workshops for the purpose to provide scientific evidence to serve young people to make a correct decision respect the tobacco consumption.

A green ultrasonic-assisted liquid–liquid microextraction technique based on deep eutectic solvents for flame atomic absorption spectrometer determination of trace level of lead in tobacco and food samples

A novel and green ultrasonic-assisted liquid phase microextraction method (LPME) based on deep eutectic solvents (DESs) has been developed for the pre-concentration and extraction of lead from cigarette tobacco and food samples prior to flame atomic absorption spectrometer (FAAS) determination. Multivariate Plackett–Burman design has been employed which make the proposed method more easy and fast as compare to routine practices and eliminated the step by step optimization process. Further, accuracy of the developed UA-DES-LPME has been checked with analysis of certified reference material and addition-recovery experiments for tobacco and food samples. The developed method showed a 4.4 µg L− 1 of limit of detection (LOD) and 14.6 µg L− 1 of limit of quantification (LOQ) with the 4.0% of relative standard deviation (RSD). Moreover, the developed method is more user-friendly, faster, and easier as compared to reported methods.

Construction of global and robust near-infrared calibration models based on hybrid calibration sets using Partial Least Squares (PLS) regression

Near-infrared spectroscopy (NIR) models built on a particular instrument are often invalid on other instruments due to spectral inconsistencies between the instruments. In the present work, global and robust NIR calibration models were constructed by partial least square (PLS) regression based on hybrid calibration sets, which are composed of both primary and secondary spectra. Three datasets were used as case studies. The first consisted of 72 radix scutellaria samples measured on two NIR spectrometers with known baicalin content. The second was composed of 80 corn samples measured on two instruments with known moisture, oil, and protein concentrations. The third dataset included 279 primary samples of tobacco with known nicotine content and 78 secondary samples of tobacco with known nicotine concentrations. The effect of the number of secondary spectra in the hybrid calibration sets and the methods for selecting secondary spectra on the PLS model performance were investigated by comparing the results obtained from different calibration sets. This study shows that the global and robust calibration models accurately predicted both primary and secondary samples as long as the ratios of the number of primary spectra to the number of secondary spectra were less than 22. The models performance was not influenced by the selection method of the secondary spectra. The hybrid calibration sets included the primary spectral information and also the secondary spectra; information, rendering the constructed global and robust models applicable to both primary and secondary instruments.

Radio frequency heat treatment for controlling cigarette beetle in dried tobacco: Poster

Tobacco (Nicotiana tabacum L.) is one of many agricultural commodities produced in Thailand. There are Virginia (flue-cured tobacco) and Burley (air-cured tobacco) typesand Cigarette beetle, Lasioderma sericorne F. is the most important insect pest that attacks dried tobacco. The efficacy of radio frequency (RF) heat treatment at 27.12 MHz was examined to control cigarette beetle on dried tobacco. Various growth stages of cigarette beetle were prepared within samples of dried tobacco and were exposed to RF at 55, 60, and 65 °C for 1, 2 and 3 minutes. The results showed that pupal and adult stages of cigarette beetle were the most tolerant stages to RF heat treatments. The RF treatment at 65 °C for 3 minutes is able to cause complete mortality of egg, larval, pupal and adult stages of cigarette beetle4.

Effects of mulching duration on PAEs accumulation in soil and tobacco leaves in Zunyi, China.

We examined the effects of the duration of plastic film mulching on the accumulation of phthalate (PAEs) in soils and tobacco to determine the soil pollution distribution characteristics of PAEs under continuous mulch use and the enrichment status in tobacco leaves. Samples of both soils and tobacco leaves were collected from Lianqian Village and Shawan Village of Zunyi. Gas chromatography-mass spectrometry (GC-MS) was used to determine the contents of six preferentially controlled PAEs in samples. The results showed that the six ΣPAEs in all soil and tobacco samples were (2.66 ±0.60) and (3.58±0.64) mg·kg-1, of which the content of DEHP was the highest, followed by DBP, with the sum of those two accounting for 92.7% and 88.9% of ∑PAEs in the soil and tobacco, respectively. The detection rates of DEHP, DBP, DEP, and BBP were 100.0%. The detection rate of DMP was slightly lower, and that of DnOP was the lowest. The content of PAEs in soils and tobacco leaves significantly increased with the increases of mulching years. In the 1-8 years of film mulching, the increases of PAEs were more obvious and tended to be gentle in the later stage. The content of PAEs in soil and tobacco leaves had significant positive correlation with the years of film mulching, indicating that the increase of film mulching years could significantly promote the accumulation of PAEs. There was no significant correlation between the ∑PAEs accumulation between tobacco leaves and soil.