Determination of pyridine, 2-picoline, 4-picoline and quinoline from mainstream cigarette smoke by solid-phase extraction liquid chromatography/electrospray ionization tandem mass spectrometry

Facile synthesis and eco-friendly analytical methods for concurrent estimation of selected pharmaceutical drugs in their solutions: application to quality by design, lean six sigma, and stability studies

Economical, highly robust, selective, precise, and eco-friendly RP-UPLC and spectrophotometric methods were developed and validated for the concurrent estimation of selected pharmaceutical drugs represented in ceftazidime (CFZ) and pyridine (PYD) in their solutions using Agilent Zorbax SB-C18 RRHD (50 × 2.1 mm, 1.8 μm) column at flow rate 0.3 mL/min with wavelength 254 nm. Box-Behnken design (BBD) established Response surface methodology (RSM) to achieve the optimum chromatographic condition with minimal trials conducted. Three independent variables specifically acetonitrile ratio 60-70%, pH 3-7, and temperature 25-35 °C were implemented to evaluate the influences of these variables on the responses as resolution and retention time. Desirability and overlay plots were carried out to adjust the optimal condition that achieved the shortest retention time of less than 2 min and desired resolution of more than 1.5 using a mobile phase consisting of acetonitrile: purified water (70:30, v/v) at pH 5.0 adjusted by 0.1% orthophosphoric acid with the column oven temperature 30 °C and column void volume 0.46 mL. Mean centering of ratio spectra (MCR) and ratio subtraction (RS) methods were effectively applied to resolve drugs' spectral superposition at 220 nm, 255.4 nm, 260.3 nm, and 254.6 nm for CFZ and PYD, respectively. Linearity range was accomplished for UPLC, MCR, and RS methods over the concentration range of 2-100, 1-50,3-30 and 5-30 µg/mL for CFZ and PYD, respectively with correlation coefficient > 0.999 and good recovery results within 98-102%. Six Sigma methodology was achieved using the process capability index (Cpk) to compare the suggested and USP methods showing that both are highly capable with Cpk > 1.33. The proposed method was successfully validated depending on ICH guidelines and ANOVA results and applied for the accelerated stability study.

Carcinogenic components of tobacco and tobacco smoke: A 2022 update

Tobacco and tobacco smoke contain a complex mixture of over 9500 chemical compounds, many of which have been recognized as hazardous to human health by regulatory agencies. In 2012, the U.S. Food and Drug Administration established a list of harmful and potentially harmful constituents in unburned tobacco and tobacco smoke, 79 of which are considered as carcinogens. Over the past 10 years, with advancing analytical technology, significant amounts of new data have been published, increasing our understanding of levels of carcinogens in tobacco products. The International Agency for Research on Cancer (IARC) has released 35 monographs since 2012, with an increasing number of compounds in unburned tobacco and tobacco smoke classified as carcinogens. In this paper, we provide an updated list of IARC-classified carcinogens in unburned tobacco and tobacco mainstream smoke. A total of 83 carcinogens has been identified - 37 in unburned tobacco and 80 in tobacco smoke - with their occurrence levels reported since 2012. No clear decreasing trends were observed for any of these carcinogens in recent years. Surveillance of the levels of tobacco carcinogens as well as regulatory actions are needed to ensure control of their levels so that potential reduced risks of cancer and other diseases may be achieved.

Content of toxic components of cigarette, cigarette smoke vs cigarette butts: A comprehensive systematic review

The commercially sold cigarettes contain more than 7000 chemicals, and their combustion produces potential toxicants in mainstream smoke (MS), sidestream smoke (SS), secondhand smoke (SHS), thirdhand smoke (THS), and discarded cigarette butts (CBs). We conducted a systematic review of published literature to compare the toxicants produced in each of these phases of tobacco combustion (MS, SS, and CBs). The initial search included 12,301 articles, but after screening and final restrictions considering the aims of this review, 159 published studies were selected for inclusion. Additionally, SHS and THS are briefly discussed here. Overall, polycyclic aromatic hydrocarbons (PAHs) and other aromatic hydrocarbons have been represented in more studies than other compounds. However, metals and nitrosamines were detected in higher concentrations than other components in SS. The concentrations of most PAHs and other aromatic hydrocarbons in MS and SS are higher compared to concentrations found in CBs. Also, the concentrations of all the studied carbonyl compounds, aldehydes and ketones in SS and MS were higher than in CBs. The mean levels of alcohols and phenols in SS were higher than those reported for both MS and CBs. Tobacco toxicants are inhaled by smokers and transmitted to the environment through SS, SHS, THS, and discarded CBs. However, further studies are necessary to assess adverse effects of toxicants found in CBs and THS not only on human health, but also on the environment and ecosystems. The results of this review provide updated information on the chemical contents of MS, SS, SHS, THS, and CBs. It adds to the growing understanding that smoking creates major health problems for smokers and passive smokers, but also that it generates environmental hazards with consequences to the ecosystems and human health through discarded CBs, SHS, and THS exposure.

Pyridine Detection Using Supramolecular Organic Frameworks Incorporating Cucurbit[10]uril

A physical impregnation method is presented in this study, providing a facile approach to encapsulating functional guest molecules (GMs) into robust crystalline supramolecular organic frameworks incorporating cucurbit[10]uril (Q[10]-SOF). As Q[10]-SOF has high evaporated pyridine affinity under normal atmospheric pressure, pyridine molecules in this method were successfully encapsulated into the nanospace formed by GMs and Q[10]-SOF while retaining their crystal framework, morphology, and high stability. GMs@Q[10]-SOF solid materials were found to respond to pyridine, being suitable to be used as solid sensors. Notably, Q[10]-SOF loading with pyrene exhibited a unique response to pyridine along with dramatic fluorescence quenching; loading with dansyl chloride exhibited a unique response to pyridine along with significant fluorescence enhancement, having a quick response within 60 s. Our findings represent a critical advancement in the design of pyridine detection and adsorption for commercial gas identification and sensing.

A multiresidue method for the analysis of pesticides, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls in snails used as environmental biomonitors

This paper reports an optimized multiresidue extraction strategy based on the Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) extraction procedure and on solid-phase microextraction (SPME) for the simultaneous screening of 120 pesticides, 16 polycyclic aromatic hydrocarbons, and 22 polychlorinated biphenyls from the terrestrial snail Helix aspersa. The optimized extraction method was based on QuEChERS using acetonitrile, followed by dispersive-Solid-phase extraction clean-up using primary secondary amine and octadecyl (C18) sorbents. The obtained extracts were analyzed by liquid chromatography coupled with tandem mass spectrometry and gas chromatography coupled with tandem mass spectrometry. This latest technique was preceded by a pre-concentration step using SPME with appropriate fibers. Afterwards, the method was validated for its linearity, sensitivity, recovery, and precision. Results showed high sensitivity, accuracy, and precision, with limits of detection and quantification lower than 20 ng g ^- 1 for most considered pollutants. Both inter and intra-day analyses revealed low relative standard deviation (%), which was lower than 20% for most targeted compounds. Moreover, the obtained regression coefficient (R²) was higher than 0.98 and the recoveries were higher than 60% for the majority of the assessed pollutants.

Preparative separation of structural isomeric pentacyclic triterpene oleanolic acid and ursolic acid from natural products by pH-zone-refining countercurrent chromatography

In this work, pH-zone-refining countercurrent chromatography was investigated in the preparative separation of two bioactive components, oleanolic acid and ursolic acid, from three different natural products, Aralia chinensis, apple peels and Eriobotrya japonica Thunb. Oleanolic acid and ursolic acid are structurally isomeric pentacyclic triterpene acids that are widely distributed in many natural products. However, it was difficult to separate these components with high purity by conventional methods. A biphasic solvent system composed of n-hexane–dichloromethane–methanol–water (7 : 3 : 2 : 8, v/v) was selected, in which an optimized concentration of 10 mmol L⁻¹ trifluoroacetic acid was added in the upper phase as the retainer and 10 mmol L⁻¹ ammonia (with 25–28% NH₃) was added in the aqueous phase as the eluter. Consequently, 38.56 mg of oleanolic acid with 99.01% purity was separated from 100 mg of the crude extract of Aralia chinensis, while 65.6 mg of a mixture of ursolic acid (90.98%) and oleanolic acid (6.51%) and 46.6 mg of a mixture of ursolic acid (74.35%) and oleanolic acid (23.61%) were separated from 100 mg of the crude extract of apple peels and 100 mg of the crude extract of Eriobotrya japonica Thunb., respectively, by pH-zone-refining countercurrent chromatography using the above selected biphasic solvent system. The results showed that pH-zone-refining countercurrent chromatography is an efficient method for the preparative separation of pentacyclic triterpene acids from natural products.

pH-zone-refining countercurrent chromatography was investigated in preparative separation of oleanolic acid and ursolic acid from three different natural products, Aralia chinensis, apple peels and Eriobotrya japonica Thunb.

Mass transfer investigation in a horizontal–vertical pulsed packed extraction column

In this study, hydrodynamic parameters and the mass transfer coefficient were investigated in a pilot plant of a horizontal–vertical pulsed packed extraction column using a toluene–acetone–water system.

New sorbents based on poly(methacrylic acid-TRIM) and poly(vinylimidazole-TRIM) for simultaneous preconcentration of herbicides in water samples with posterior determination by HPLC-DAD

In the present study, poly(methacrylic acid-trimethylolpropane trimethacrylate) (PMA-TRIM) and poly(vinylimidazole-TRIM) (PV-TRIM) have been used for simultaneous extraction of tebuthiuron, hexazinone, diuron, and ametryn with posterior determination by HPLC-DAD.

Direct analysis of anabolic steroids in urine using Leidenfrost phenomenon assisted thermal desorption-dielectric barrier discharge ionization mass spectrometry

Rapid detection of trace level anabolic steroids in urine is highly desirable to monitor the consumption of performance enhancing anabolic steroids by athletes. The present article describes a novel strategy for identifying the trace anabolic steroids in urine using Leidenfrost phenomenon assisted thermal desorption (LPTD) coupled to dielectric barrier discharge (DBD) ionization mass spectrometry. Using this method the steroid molecules are enriched within a liquid droplet during the thermal desorption process and desorbed all-together at the last moment of droplet evaporation in a short time domain. The desorbed molecules were ionized using a dielectric barrier discharge ion-source in front of the mass spectrometer inlet at open atmosphere. This process facilitates the sensitivity enhancement with several orders of magnitude compared to the thermal desorption at a lower temperature. The limits of detection (LODs) of various steroid molecules were found to be in the range of 0.05-0.1 ng mL(-1) for standard solutions and around two orders of magnitude higher for synthetic urine samples. The detection limits of urinary anabolic steroids could be lowered by using a simple and rapid dichloromethane extraction technique. The analytical figures of merit of this technique were evaluated at open atmosphere using suitable internal standards. The technique is simple and rapid for high sensitivity and high throughput screening of anabolic steroids in urine.

Automated preconcentration and analysis of organic compounds by on-line hollow fiber liquid-phase microextraction-high performance liquid chromatography

The present work describes the first automated instrument, based on on-line hollow fiber liquid-phase microextraction (HF-LPME)-high performance liquid chromatography (HPLC), for the preconcentration and determination of organic compounds in various matrices. Using an automated syringe pump for loading the supported liquid membrane and acceptor solvents, a platform lift for moving the sample vial, a sampling loop for on-line injection of the extract to HPLC, along with an electronic board with an AVR microcontroller for storage of data and instrument programs, a sample preparation-HPLC method was developed that allowed sample extraction and extract injection to be carried out completely automatically. Pyridine and pyridine derivatives were chosen for the development and for testing the applicability of the automated instrument. The limits of detection (3 times the S/N) ranged from 0.5 to 1.0 μgL(-1). Effective preconcentration of the analytes was also achieved (preconcentration factors of between 40 and 220). The main advantages of the method developed are minimum sample manipulation, full automation, suitable extraction time, low solvent consumption, and ease of use. The applicability of the on-line automated HF-LPME/HPLC-UV instrument was validated for quantitative extraction and determination of pyridines in cigarette smoke.

Rapid determination of pyridine derivatives by dispersive liquid-liquid microextraction coupled with gas chromatography/gas sensor based on nanostructured conducting polypyrrole

Polypyrrole (PPy) gas sensor has been prepared by polymerization of pyrrole on surfaces of commercial polymer fibers in the presence of an oxidizing agent. The sensing behavior of PPy gas sensor was investigated in the presence of pyridine derivatives. The resistive responses of the PPy gas sensor to pyridine derivatives were in the order of quinoline>pyridine>4-methyl pyridine and 2-methyl pyridine. The PPy gas sensor was used as gas chromatography (GC) detector and exhibited linear responses to pyridine derivatives in the ranges 40-4,000 ng. Dispersive liquid-liquid microextraction (DLLME) combined with GC/PPy gas sensor has been developed for simultaneous determination of pyridine derivatives and quinoline. The purposed method was used for determination of pyridine derivatives from cigarette smoke. The GC runs were completed in 4 min. The reproducibility of this method is suitable and good standard deviations were obtained. RSD value is less than 10% for all analytes.

Rapid determination of quinoline and 2-hydroxyquinoline in quinoline biodegradation process by tri-wavelength UV/Vis spectroscopy

For the present study, a tri-wavelength UV/Vis spectrophotometric method for rapid determination of quinoline (Q) and 2-hydroxyquinoline (HQ) during Q biodegradation was developed. Based on the spectral measurements at 289 nm (the isosbestic point of Q and HQ), 326 and 380 nm, the spectral interference of extracellular polymeric substances (EPS) in the process samples could be minimized, and the amounts of Q and HQ could be simultaneously quantified. Our results indicated that the relative standard deviations in the repeatability tests were 2.7 and 1.7% for Q and HQ, respectively. The method validation was conducted by comparing the data obtained using the present method with those generated from high performance liquid chromatography (HPLC). The same set of samples from Q biodegradation process was used. The relative differences between the two methods were within 10%. In conclusion, the present method is simple, rapid, and suitable for the investigation in Q biodegradation processes.