Unraveling the cytotoxicity and cellular uptake of low, medium and high molecular weight polyethylene glycol polymers in MCF-7 cells by green UPLC-MS/MS methods

Unraveling the cytotoxicity and cellular uptake of low, medium and high molecular weight polyethylene glycol (PEG) in cells is important for evaluation of therapeutic efficacy and toxicity of PEGylated drug delivery systems. In this study, cellular uptake of PEG600, PEG2K, PEG4K and PEG10K in MCF-7 cells was first studied by an UPLC-MS/MS assay coupled with collision induced dissociation (CID) in source technique. The CID of PEG in source with high values of declustering potentials generates numerous PEG-related product ions. These PEG-related fragment ions can be further broken into specific product ions in the collision cell as alternative ions for detection of PEG. The quantification of PEG was finally performed with the MRM transition (m/z 221.0 → 89.0). The experimental results indicated that the toxicity of PEG600, PEG2K, PEG4K and PEG10K was not significant at concentrations of 5-1200 μg/mL and the amounts of PEG polymers entry into MCF-7 cells at was small. The greenness of the developed analytical methods was also assessed by Analytical Eco-Scale, Analytical Greenness calculator (AGREE) and Green Analytical Procedure Index (GAPI) in this study.

Rapid In-Field Volatile Sampling for Detection of Botrytis cinerea Infection in Wine Grapes

Fungal infection of grape berries (Vitis vinifera) by Botrytis cinerea frequently coincides with harvest, impacting both the yield and quality of grape and wine products. A rapid and non-destructive method for identifying B. cinerea infection in grapes at an early stage prior to harvest is critical to manage loss. In this study, zeolitic imidazolate framework-8 (ZIF-8) crystal was applied as an absorbent material for volatile extraction from B. cinerea infected and healthy grapes in a vineyard, followed by thermal desorption gas chromatography-mass spectrometry. The performance of ZIF-8 in regard to absorbing and trapping the targeted volatiles was evaluated with a standard solution of compounds and with a whole bunch of grapes enclosed in a glass container to maintain standard sampling conditions. The results from the sampling methods were then correlated to B. cinerea infection in grapes, as measured and determined by genus-specific antigen quantification. Trace levels of targeted compounds reported as markers of grape B. cinerea infection were successfully detected with in-field sampling. The peak area counts for volatiles 3-octanone, 1-octen-3-one, 3-octanol, and 1-octen-3-ol extracted using ZIF-8 were significantly higher than values achieved using Tenax^®-TA from field testing and demonstrated good correlation with B. cinerea infection severities determined by B. cinerea antigen detection.

Research progress of N-nitrosamine detection methods: a review

N-Nitrosamines (nitrosamines) are attracting increased attention because of their high toxicity and wide distribution. They have been strictly restricted by regulations in many fields. Researchers around the world have conducted substantial work on nitrosamine detection. This paper reviews the progress of research on nitrosamine detection methods with emphasis on biological-matrix samples. After introducing the category, toxicity, regulatory limit and source of nitrosamines, the paper discusses the most commonly used sample-preparation techniques and instrumental-detection techniques for nitrosamine detection, including some typical application cases.

Development and validation of rapid ultra high performance liquid chromatography with tandem mass spectroscopic method for the quantification of N-Nitrosodimethyl amine and N-Nitrosodiethyl amine in sitagliptin and metformin hydrochloride immediate and extended-release formulations

A simple, effective LC-MS based method is developed and validated to determine N-Nitrosodimethylamine and N-Nitrosodiethylamine in pharmaceutical formulations of Sitagliptin and Metformin hydrochloride combination dosage forms. Atlantis T3 (100 × 3 mm, 3 μm) column and eluent-A (0.1% formic acid in water), and eluent-B (0.1% formic acid in methanol) were used to achieve chromatographic separation. A gradient program time (min)/%B: 0.01/3, 2/3, 4/55, 5/55, 5.5/90, 6.0/90, 6.5/3 and 7/3, and column flow rate: 0.75 mL/min was employed. The column oven and auto sample cooler temperatures were 40°C and 10°C, respectively. Atmospheric Pressure Ionisation +ve mode with corona discharge potential as 4.0 volts, drying gas (N₂ ) flow as 110 mL/min, and nebulizer gas (N₂ ) flow as 350 mL/min. Employing PerkinElmer triple quadrupole mass spectrometer, QSight 200 series, the source temperature was 450°C, and hot surface-induced desolvation temperature was 250°C. Under optimized conditions, diluent-1 and diluent-2 offered better recovery and improved peak shapes. The required method sensitivity of Nitrosodimethylamine (Limit of Quantitation 0.74 ng mL^-1 ) and Nitrosodiethylamine (Limit of Quantitation 0.37 ng mL^-1 ) for the nitrosamine impurities were achieved using an optimized test concentration of Metformin hydrochloride at 45.7 mg mL^-1 . This article is protected by copyright. All rights reserved.

Unsymmetrical dimethylhydrazine and related compounds in the environment: Recent updates on pretreatment, analysis, and removal techniques

Unsymmetrical dimethylhydrazine (1,1-Dimethylhydrazine, UDMH) has been widely used as aerospace fuel in many countries. The launch of space vehicles can cause the release and leakage of UDMH into the environment, posing serious threats to ecology system and human population. Even worse, the health risks are also pertinent to its numerous classes of transformation products including N-Nitrosodimethylamine (NDMA), because most of them display carcinogenic and mutagenic properties. Recently, there has been an intense ongoing development of simple, fast, green, and effective techniques for determining and removing these hazardous substances. This review summarizes the latest research progress regarding the sources, fates, pretreatment, analysis, and removal techniques of UDMH and related products in the environment. Sample preparation methods mainly include pressurized liquid extraction, liquid-phase microextraction techniques, solid-phase extraction, headspace-solid-phase microextraction, and supercritical fluid extraction. Detection and identification methods mainly include high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS), gas chromatography coupled with tandem mass spectrometry (GC-MS/MS), and sensors. Removal methods mainly include advanced oxidation processes, adsorption, biodegradation techniques. The advantages/disadvantages, applications, and trends of the proposed approaches are thoroughly discussed to provide a valuable reference for further studies.

Nitrocellulose blister material as a source of N-nitrosamine contamination of pharmaceutical drug products

The recent focus of pharmaceutical regulatory authorities has been oriented towards the mitigation of carcinogenic N-nitrosamines in drug products and different sources of N-nitrosamines have been revealed. Within this work, the elucidation of a further source of N-nitrosamines in drug products is reported. A case was investigated where traces of N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) were detected in a finished dosage form, whereas they were not found in the bulk drug product. This led to an in-depth study of blister material as a potential source, wherein nitrocellulose primer in a lidding foil was identified as a risk factor. Nitrocellulose acts as a nitrosating agent for secondary amines, present in printing inks, forming N-nitrosamines in lidding foil. Their formation was confirmed by the addition of printing ink containing dimethylamine and diethylamine, or diethylamine alone, to lidding foil containing nitrocellulose primer. Their transfer to drug product during the blistering operation was demonstrated by solid-phase microextraction sampling of N-nitrosamine vapors on two commonly used types of pharmaceutical blistering machines, operating with plate sealing or roller sealing technology. Higher vapor amounts were detected on plate sealing equipment, where N-nitrosamine contamination was additionally confirmed in film-coated tablets and blister cavities of the finished dosage form.

Preparation of flower-like molybdenum disulfide for solid-phase extraction of N-nitrosoamines in environmental water samples

In this paper, a flower-like molybdenum disulfide material was prepared by hydrothermal method and was first used as adsorbents in the solid-phase extraction process for enriching N-nitrosoamines. Molybdenum disulfide exhibited three-dimensional petal-like microspheres with about 500 nm in diameter. The relevant analyte extraction and elution parameters (sample volumes, solution pH, washing solvents, elution solvents, and elution volumes) were optimized to improve the solid-phase extraction efficiency. The solid-phase extraction process coupled with high-performance liquid chromatography-tandem mass spectrometry for determining N-nitrosoamines in environmental water samples was established. The limits of detection were in the range of 0.01-0.05 ng/mL. The satisfactory recoveries (68.9-106.1%) were obtained at three different spiked concentrations (2, 5, and 8 ng/mL) in water samples, and the relative standard deviations were between 1.96 and 8.38%. This proposed method not only showed high sensitivity and good reusability but also provided a new adsorbent for enriching trace N-nitrosoamines in environmental water samples.

Quantification of transformation products of rocket fuel unsymmetrical dimethylhydrazine in air using solid-phase microextraction

Quantification of unsymmetrical dimethylhydrazine transformation products in ambient air is important for assessing the environmental impact of heavy rocket launches. There are very little data of such analyses, which is mainly caused by the low number of analytes covered by the available analytical methods and their complexity. A simple and cost-efficient method for accurate simultaneous determination of seven unsymmetrical dimethylhydrazine transformation products in air using solid-phase microextraction followed by gas chromatography-mass spectrometry was developed. The method was optimized for air sampling and solid-phase microextraction from 20-mL vials, which allows full automation of analysis. The extraction for 5 min by Carboxen/polydimethylsiloxane fiber from amber vials and desorption for 3 min provided the greatest analytes' responses, lowest relative standard deviations, linear calibration (R² ≥ 0.99), and limits of detection from 0.12 to 0.5 μg/m³ . Samples with concentrations 500 μg/m³ can be stored at 21 ± 1°C without substantial losses (1-11%) for up to 24 h, while air samples with concentrations 10 and 50 μg/m³ stored for up to 24 h can be used for accurate quantification of only two and four out of seven analytes, respectively. The developed method was successfully tested for the analysis of air above real soil samples contaminated with unsymmetrical dimethylhydrazine rocket fuel.

Progress in the pretreatment and analysis of N-nitrosamines: an update since 2010

As highly toxic substances, N-nitrosamines (NAs) have been proved to cause carcinogenesis and mutagenesis in humans. Therefore, to carefully monitor safety and preserve human health, the development of rapid, accurate, and high-sensitivity determination methods of NAs is of substantial importance. This review provides a current-status comprehensive summary of the pretreatment and determination methods of NAs in various samples since 2010. Common pretreatment methods that have been used to extract and purify targets include solid-phase extraction, liquid-liquid extraction and various microextraction methods, such as solid-phase microextraction and liquid-phase microextraction, among others. Determination methods include liquid chromatography, gas chromatography, supercritical fluid chromatography and electrochemical methods, among others. In addition, we discuss and compare the advantages and disadvantages of various pretreatment and analytical methods and examine the prospects in this area.

Determination of N-Nitrosamines by Gas Chromatography Coupled to Quadrupole–Time-of-Flight Mass Spectrometry in Water Samples

An analytical method based on high-resolution quadrupole–time-of-flight (QToF) mass spectrometry has been developed as an alternative to the classical method, using a low-resolution ion trap (IT) analyzer to reduce interferences in N-nitrosamines determination. Extraction of the targeted compounds was performed by solid-phase extraction (SPE) following the United States Environmental Protection Agency (USEPA) -521 method. First, both electron impact (EI) and positive chemical ionization (PCI) using methane as ionization gas were compared, along with IT and QToF detection. Then, parameters such as limits of detection (LOD) and quantification (LOQ), linearity, and repeatability were assessed. The results showed that the QToF mass analyzer combined with PCI was the best system for the determination of the N-nitrosamines, with instrumental LOD and LOQ in the ranges of 0.2–4 and 0.6–11 ng mL−1, respectively, which translated into method LOD and LOQ in the ranges of 0.2–1.3 and 0.6–3.9 ng L−1, respectively. The analysis of real samples showed the presence of 6 of the N-nitrosamines in influent, effluent, and tap water. N-nitrosodimethylamine (NDMA) was quantified in all the analyzed samples at concentrations between 1 and 27 ng L−1. Moreover, four additional nitrosamines were found in tap and wastewater samples.

Quantification of transformation products of unsymmetrical dimethylhydrazine in aqueous extracts from soil based on vacuum-assisted headspace solid-phase microextraction

Quantification of transformation products of unsymmetrical dimethylhydrazine (UDMH) in soil requires tedious, time- and labor-consuming sample preparation. The simple and fast method for quantification of transformation products of UDMH in aqueous extracts from soil using vacuum-assisted headspace solid-phase microextraction (Vac-HSSPME) was optimized in this work. The method is based on extraction of analytes from soil with water followed by Vac-HSSPME of the obtained aqueous extracts, and gas chromatography-mass spectrometry analysis. The target transformation products were: pyrazine, 1-methyl-1H-pyrazole, N-nitrosodimethylamine, N,N-dimethylformamide, 1-methyl-1Н-1,2,4-triazole, 1-methyl-imidazole and 1H-pyrazole. The effect of a sample pH on responses of target analytes was studied. It was negligible, and no pH adjustment was recommended before a subsequent extraction. The water amount was optimized to provide the best combination of analytes responses and their precision. Extraction by adding 7.00 mL of water to 2.0 g of soil ensured linear dependence of responses of the analytes on their concentrations in soil. The optimized method provided detection limits of target analytes in soil in the range from 0.2 to 9 ng/g. The spike recoveries obtained for model samples were in the range 90-103%. The developed method can be recommended for application in laboratories conducting routine analyses of soil samples potentially contaminated by rocket fuel residuals.

Ordered mesoporous carbon as sorbent for the extraction of N-nitrosamines in wastewater and swimming pool water

The analysis and determination of N-nitrosamines (NAs) in water samples are challenging and demanding. In this study, a simple, reliable, and practical methodology is reported for the quantitative determination by gas chromatography-tandem mass spectrometry with electron impact ionization (EI) and triple quadrupole analyzer (GC-EI-MS/MS) of eight NAs after micro-solid-phase extraction (μ-SPE) from wastewater and swimming pool water. Thirty milligram of an ordered mesoporous carbonaceous material, oxidative surface-modified CMK-3, enclosed within a porous polypropylene membrane bag, were used as sorbent for μ-SPE. A central composite design approach was applied to optimize the μ-SPE parameters. An isotopically-labeled NA was used as internal standard. Under the optimized conditions, μ-SPE-GC-EI-MS/MS was validated for an NA concentration range of between 0.1-100ng/mL. The precision of the method was evaluated and an average relative standard deviation of 4.8% (n=8) for a standard solution spiked at 50ng/mL of each NA was obtained. The limits of detection were measured to be in the range of 0.005-0.283ng/mL. Domestic wastewater and swimming pool water samples were used to evaluate the applicability of the method. NAs were detected in swimming pool water and wastewater at concentrations of <2ng/mL and 11ng/mL, respectively.

Determination of nine volatile N-nitrosamines in tobacco and smokeless tobacco products by dispersive solid-phase extraction with gas chromatography and tandem mass spectrometry

A method was developed for the determination of nine volatile N-nitrosamines in tobacco and smokeless tobacco products. The targets are N-nitrosodimethylamine, N-nitrosopyrrolidine, N-nitrosopiperidine, N-nitrosomorpholine, N-nitrosoethylmethylamine, N-nitrosodiethylamine, N-nitrosodipropylamine, N-nitrosobuylmethylmine, and N-nitrosodibutylamine. The samples were treated by dispersive solid-phase extraction using 1 g of primary secondary amine and 0.5 g of carbon and then analyzed by gas chromatography with tandem mass spectrometry with an electron impact ion source. The recoveries for the targets ranged from 84 to 118%, with <16% relative standard deviations at three spiking levels of 0.5, 1.25, and 2.5 ng/g. The limits of detection ranged from 0.03 to 0.15 ng/g. With the use of the proposed method, we detected the presence of six nitrosamines in the range of 0.4-30.7 ng/g. The study demonstrated that the method could be used as a rapid, convenient, and high-throughput method for N-nitrosamines analysis in tobacco matrix.

Evaluation of a method for the simultaneous quantification of N-nitrosamines in water samples based on stir bar sorptive extraction combined with high-performance liquid chromatography and diode array detection

A simple, sensitive, and reliable procedure based on stir bar sorptive extraction coupled with high-performance liquid chromatography was applied to simultaneously extract and determine three semipolar nitrosamines including N-nitrosodibutylamine, N-nitrosodiphenylamine, and N-nitrosodicyclohexylamine. To achieve the optimum conditions, the effective parameters on the extraction efficiency including desorption solvent and time, ionic strength of sample, extraction time, and sample volume were systematically investigated. The optimized extraction procedure was carried out by stir bars coated with polydimethylsiloxane. Under optimum extraction conditions, the performance of the proposed method was studied. The linear dynamic range was obtained in the range of 0.95-1000 ng/mL (r = 0.9995), 0.26-1000 ng/mL (r = 0.9988) and both 0.32-100 ng/mL (r = 0.9999) and 100-1000 ng/mL (r = 0.9998) with limits of detection of 0.28, 0.08, and 0.09 ng/mL for N-nitrosodibutylamine, N-nitrosodiphenylamine, and N-nitrosodicyclohexylamine, respectively. The average recoveries were obtained >81%, and the reproducibility of the proposed method presented as intra- and interday precision were also found with a relative standard deviation <6%. Finally, the proposed method was successfully applied to the determination of trace amounts of selected nitrosamines in various water and wastewater samples and the obtained results were confirmed using mass spectrometry.

Determination of N-nitrosamines by automated dispersive liquid-liquid microextraction integrated with gas chromatography and mass spectrometry

An automated dispersive liquid-liquid microextraction integrated with gas chromatography and mass spectrometric procedure was developed for the determination of three N-nitrosamines (N-nitroso-di-n-propylamine, N-nitrosopiperidine, and N-nitroso di-n-butylamine) in water samples. Response surface methodology was employed to optimize relevant extraction parameters including extraction time, dispersive solvent volume, water sample pH, sodium chloride concentration, and agitation (stirring) speed. The optimal dispersive liquid-liquid microextraction conditions were 28 min of extraction time, 33 μL of methanol as dispersive solvent, 722 rotations per minute of agitation speed, 23% w/v sodium chloride concentration, and pH of 10.5. Under these conditions, good linearity for the analytes in the range from 0.1 to 100 μg/L with coefficients of determination (r(2) ) from 0.988 to 0.998 were obtained. The limits of detection based on a signal-to-noise ratio of 3 were between 5.7 and 124 ng/L with corresponding relative standard deviations from 3.4 to 5.9% (n = 4). The relative recoveries of N-nitroso-di-n-propylamine, N-nitrosopiperidine, and N-nitroso di-n-butylamine from spiked groundwater and tap water samples at concentrations of 2 μg/L of each analyte (mean ± standard deviation, n = 3) were (93.9 ± 8.7), (90.6 ± 10.7), and (103.7 ± 8.0)%, respectively. The method was applied to determine the N-nitrosamines in water samples of different complexities, such as tap water, and groundwater, before and after treatment, in a local water treatment plant.

Determination of N-nitrosamines and nicotine in air particulate matter samples by pressurised liquid extraction and gas chromatography-ion trap tandem mass spectrometry

N-nitrosamines are potentially hazardous pollutants, classified as probable carcinogenic and mutagenic by the U.S. Environmental Protection Agency (EPA). In this paper, the presence of these pollutants was studied in air samples taken at different locations of Tarragona (urban and harbour). As a result, a reliable method has been developed for determining N-nitrosamines and nicotine based on pressurised liquid extraction (PLE) and gas chromatography-(chemical ionisation) ion trap tandem mass spectrometry (GC-(CI)MS/MS). The chromatographic analysis enables the determination of these compounds in less than 13 min with total separation and good resolution between the compounds. Recovery values were higher than 80% for most of the compounds and the repeatability of the method was under 18% (5 ng m(-3), %RSD, n=4). MDLs were between 0.1 ng m(-3) (NMor and NPip) and 2 ng m(-3) (NMEA). NMor, NPyr, NPip and nicotine were the most frequent compounds in urban and harbour samples at concentration levels between 0.3 ng m(-3) (NPyr) and 12.5 ng m(-3) (nicotine) and between 0.13 ng m(-3) (NPyr) and 3.8 ng m(-3) (nicotine), respectively.

Dispersive micro-solid phase extraction combined with gas chromatography-chemical ionization mass spectrometry for the determination of N-nitrosamines in swimming pool water samples

A simple sample pretreatment technique, dispersive micro-solid phase extraction, was applied for the extraction of N-nitrosodimethylamine (NDMA) and other four N-nitrosamines (NAs) from samples of swimming pool water. The parameters affecting the extraction efficiency were systematically investigated. The best extraction conditions involved immersing 75 mg of carbon molecular sieve, Carboxen™ 1003 (as an adsorbent), in a 50-mL water sample (pH 7.0) containing 5% sodium chloride in a sample tube. After 20 min of extraction by vigorous shaking, the adsorbent was collected on a filter and the NAs desorbed by treatment with 150 μL of dichloromethane. A 10-μL aliquot was then directly determined by large-volume injection gas chromatography with chemical ionization mass spectrometry using the selected ion storage mode. The limits of quantitation were <0.9 ng/L. The precision for these analytes, as indicated by relative standard deviations, were <8% for both intra- and inter-day analyses. Accuracy, expressed as the mean extraction recovery, was between 62% and 109%. A preliminary analysis of swimming pool water samples revealed that NDMA was present in the highest concentration, in the range from n.d. to 100 ng/L.

Determination of nicotine and N-nitrosamines in house dust by pressurized liquid extraction and comprehensive gas chromatography--nitrogen chemiluminiscence detection

A novel, highly selective method for the determination of nicotine, N-nitrosamines and tobacco-specific nitrosamines (TSNAs) in indoor dust samples is presented in this study. Samples were extracted by in-cell clean-up pressurized liquid extraction (PLE) that allows high extraction efficiency with moderate consumption of organic solvents. The extracts were analyzed by comprehensive gas chromatography and detected with a nitrogen chemiluminiscence detector (GC×GC-NCD) that provided enhanced selectivity and sensitivity for organic nitrogen containing compounds. Method validation showed good linearity, repeatability and reproducibility (%RSD<8%). Recovery was higher than 80% for most target compounds and limits of detection lower than 16 ng g(-1). The method was used for the determination of the nitrosamine target compounds in house dust samples from both smoking and non-smoking households. All the analytes were found in the samples, nicotine being the most abundant compound in smokers' dust and one of the most abundant in non-smokers' dust. To our knowledge this is the first time that volatile N-nitrosamines and TSNAs have been determined in indoor dust samples. The results demonstrate the presence of these highly carcinogenic compounds in house dust, with inherent human exposure through inhalation and/or involuntary ingestion of house dust.