Solid-phase Extraction Sample Research Articles

Paper Spray Mass Spectrometry with On‐Paper Electrokinetic Manipulations: Part‐Per‐Trillion Detection of Per/Polyfluoroalkyl Substances in Water and Opioids in Urine

AbstractWe developed a simple, paper‐based device that enables sensitive detection by mass spectrometry (MS) without solid phase extraction or other sample preparation. Using glass fiber filter papers within a 3D printed holder, the device employs electrokinetic manipulations to stack, separate, and desalt charged molecules on paper prior to spray into the MS. Due to counter‐balanced electroosmotic flow and electrophoresis, charged analytes stack on the paper and desalting occurs in minutes. One end of the paper strip was cut into a sharp point and positioned near the inlet of a MS. The stacked analyte bands move toward the paper tip with the EOF where they are ionized by paper spray. The device was applied to analysis of PFAS in tap water with sub part‐per‐trillion detection limits in less than ten minutes with no sample pretreatment. Analysis of opioids in urine also occurs in minutes. The crucial parameters to enable stacking, separation, and MS ionization of both positively and negatively charged analytes were determined and optimized. Experimental and computational modeling studies confirm the electrokinetic stacking and analyte transport mechanisms. On‐paper separations were carried out by stacking analyte bands at different locations depending on their electrophoretic mobility, achieving baseline separation in some cases.

Paper Spray Mass Spectrometry with On-Paper Electrokinetic Manipulations: Part-Per-Trillion Detection of Per/Polyfluoroalkyl Substances in Water and Opioids in Urine.

We developed a simple, paper-based device that enables sensitive detection by mass spectrometry (MS) without solid phase extraction or other sample preparation. Using glass fiber filter papers within a 3D printed holder, the device employs electrokinetic manipulations to stack, separate, and desalt charged molecules on paper prior to spray into the MS. Due to counter-balanced electroosmotic flow and electrophoresis, charged analytes stack on the paper and desalting occurs in minutes. One end of the paper strip was cut into a sharp point and positioned near the inlet of a MS. The stacked analyte bands move toward the paper tip with the EOF where they are ionized by paper spray. The device was applied to analysis of PFAS in tap water with sub part-per-trillion detection limits in less than ten minutes with no sample pretreatment. Analysis of opioids in urine also occurs in minutes. The crucial parameters to enable stacking, separation, and MS ionization of both positively and negatively charged analytes were determined and optimized. Experimental and computational modeling studies confirm the electrokinetic stacking and analyte transport mechanisms. On-paper separations were carried out by stacking analyte bands at different locations depending on their electrophoretic mobility, achieving baseline separation in some cases.

One-step grafting of phenyl functionalized magnetic mesoporous nanocomposites for magnetic dispersive solid-phase extraction and determination of triazole fungicide residues in strawberry fruits

In this work, phenyl-SBA-15@Fe3O4 organic phenyl functional magnetic mesoporous materials were synthesized as adsorbent for magnetic dispersive solid phase extraction (M−DSPE) sample pretreatment. Seven triazole fungicides were simultaneously analyzed by high-performance liquid chromatography coupled with ultraviolet detection (HPLC-UV). The extraction recovery was 82.7 %-88.6 %, and the concentration factor was 10.6–30.8. Under the optimized experimental conditions, the regression equations of seven triazole fungicides showed a good linear relationship, the coefficient of determination r2 was 0.9993–0.9999, and the detection limit was 0.19 ∼ 1.75 μg·L-1. Six strawberry samples were randomly purchased from different places in the market, and flesh,cortex, sepal, and pulp were detected separately. The results showed that flutriafol, triadimenol and difenoconazole were detected, of which flutriafol was detected from all of them and most of them exceeded the national standard. The extraction pretreatment technology is fast and efficient, which can meet the requirements of simultaneous analysis of triazole fungicide residues in strawberries.

Investigating the impacts of solid phase extraction on dissolved organic matter optical signatures and the pairing with high‐resolution mass spectrometry data across a freshwater stream network

AbstractAdvancing our understanding of dissolved organic matter (DOM) chemistry in aquatic systems necessitates the integration of data streams from multiple analytical platforms. Some measurements require pretreatment with solid phase extraction (SPE), while others are performed directly on whole water samples. Evidence has suggested that SPE will be biased against select DOM fractions, leading to concerns over the ability to establish data linkages across platforms with variable needs for SPE pretreatment, such as those from optical measurements and those that provide high‐resolution molecular information. Here, we directly addressed this concern by assessing the impact of SPE on DOM optical properties through excitation–emission matrices with parallel factor analysis (PARAFAC) for 47 samples across a stream network within a single watershed reflective of variable DOM sources. PARAFAC data was further paired with molecular information obtained by Fourier transform ion cyclotron resonance mass spectrometry (FTICR‐MS). A comparison of PARAFAC models first revealed no systematic qualitative differences in major components between whole water DOM and DOM isolated by SPE (SPE‐DOM); however, quantitative biases against select components were observed. Further linkages with FTICR‐MS data revealed that the molecular fingerprint associated with each PARAFAC component was consistent between the whole water DOM and SPE‐DOM. Our results suggest that bulk scale linkages across these analytical platforms could be inferred irrespective of the observed quantitative biases resulting from SPE for samples within this example watershed. This work represents a key step toward the systematic evaluation of linkages between optical and high‐resolution mass spectrometry datasets in freshwater lotic environments.

An Ultra-High-Performance Liquid Chromatography Coupled with Tandem Mass Spectrometry Method with Online Solid-Phase Extraction Sample Preparation for the High-Throughput and Sensitive Determination of Ostarine in Human Urine.

Ostarine is frequently misused as a selective androgen receptor modulator (SARM) in sports. Consequently, there is a pressing need for reliable and simple approaches to monitor its presence in biological systems. In this work, we developed a two-dimensional analytical method utilizing online solid-phase extraction (online-SPE) in conjunction with ultra-high-performance liquid chromatography and tandem mass spectrometry (triple quadrupole). This automated 2D separation approach is characterized by minimum manual steps in the sample preparation (only dilute-and-shoot), reflecting high sample throughput and the reliability of analytical data. It provides favorable performance parameters, including a limit of detection of 0.5 pg/mL, high accuracy (relative error = 1.6-7.5%), precision (relative standard deviation = 0.8-4.5%), and sensitivity. Additionally, it demonstrates excellent linearity (r2 = 0.9999) in the calibration range of 0.05 to 25 ng/mL and robustness, with no carryover effects observed. This comparative study revealed a two-decadic-order-lower LOD of the SPE-UHPLC-MS/MS method to the corresponding UHPLC-MS/MS method and the lowest one in the group of currently published LC-MS methods. The World Anti-Doping Agency screening and confirmation criteria were met through the analysis of spiked urine samples from ten healthy volunteers. Accordingly, the proposed method is suitable for routine use in antidoping laboratories.

Targeted multi-analyte UHPLC-MS/MS methodology for emerging contaminants in septic tank wastewater, sludge and receiving surface water.

Septic tanks treat wastewater of individual houses and small communities (up to 2000 people in Scotland) in rural and semi-urban areas and are understudied sources of surface water contamination. A multi-analyte methodology with solid phase extraction (SPE), ultra-sonic extraction, and direct injection sample preparation methods was developed to analyse a comprehensive range of emerging contaminants (ECs) including prescription and over-the-counter pharmaceuticals and related metabolites, natural and synthetic hormones, and other human wastewater marker compounds in septic tank influent and effluent, river water, suspended solids, and septic tank sludge by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS). The number of quantifiable compounds in each matrix varied from 68 in septic tank wastewater to 59 in sludge illustrating its applicability across a range of matrices. Method quantification limits were 2.9 × 10-5-1.2 μg L-1 in septic tank influent, effluent and river water, with ≤0.01 μg L-1 achieved for 60% of ECs in all three water matrices, and 0.080-49 μg kg-1 in sludge. The developed method was applied to a septic tank (292 population equivalents) and the receiving river in the North-East of Scotland. Across all samples analysed, 43 of 68 ECs were detected in at least one matrix, demonstrating the method's sensitivity. The effluent concentrations suggest limited removal of ECs in septic tanks and a potential impact to river water quality for some ECs. However, further monitoring is required to better appreciate this. The developed methodology for a wide variety of ECs in a range of liquid and solid phases will allow, for the first time, a comprehensive assessment of ECs fate and removal in septic tanks, and their impact to surface water quality.

Evaluating the photochemical reactivity of disinfection byproducts formed during seawater desalination processes

Reverse osmosis (RO) is widely used for seawater desalination but pre-chlorination of intake water produces halogenated disinfection byproducts (DBPs). The fate and environmental impacts associated with the discharge of DBP-containing RO brine wastewater are unknown. Therefore, to evaluate if photochemistry plays a role in DBP degradation in seawater, we collected samples at a desalination plant, which were desalted and concentrated using two-inline solid phase extraction (SPE) techniques combining reverse-phase polymeric (PPL) and weak anion exchange (WAX) resins. Both filtered water samples and SPE samples (extracts reconstituted in open ocean seawater) were exposed to simulated sunlight in a custom-built flow-through system. Optical property analysis during irradiation experiments did not provide distinguishing features between intake water and RO reject water (brine). Extractable organic bromine (organoBr) concentrations were low in intake water samples (7.8 μg Br L−1) and did not change significantly due to irradiation. OrganoBr concentrations in laboratory-chlorinated raw water were much higher (135 μg Br L−1) and on average decreased by 42 % after 24 h irradiation. However, while organoBr concentrations were highest in RO reject water (473 μg Br L−1), changes in organoBr concentrations in PPL SPE samples after 24 h irradiation were variable, ranging from a 1–46 % loss. Furthermore, most bromine-containing molecular ions identified by high resolution mass spectrometry that were present in RO reject water before irradiation were also found after both 24 h and 50 h exposures. Although only one RO reject water sample was tested in this study, results highlight that hundreds of yet to be identified brominated DBPs in RO reject water could be resistant to photodegradation or phototransform into existing DBPs in the environment. Future work examining the biolability of DBPs in RO reject water, as well as the interplay between photochemical and biological DBP cycling, is warranted.

Evaluation of solid-phase extraction sorbents for purification of oligosaccharides and glycans derivatized by positively charged labels followed by capillary electrophoretic analysis.

The sample preparation including labeling and clean-up represents a key analytical step in the analysis of oligosaccharides and glycans by either chromatographic or electrophoretic separation methods. Although the majority of labeling has been performed by neutral and/or negatively charged tags, the introduction of a positive charge into the saccharide molecule can significantly improve the analysis, especially with mass spectrometry detection. In this work, we present the evaluation of five solid-phase extraction sorbents differing in extraction chemistry for the clean-up and concentration of positively labeled maltooligosaccharides from the reaction mixtures. Maltooligosaccharides containing four to seven glucose units were labeled by cationic tags (2-aminoethyl)trimethylammonium chloride and (carboxymethyl)trimethylammonium chloride hydrazide and the extraction conditions were optimized followed by electrophoretic analysis with conductivity detection. The effects of the solid-phase extraction sorbent chemistry, extraction conditions, and sample composition are discussed. All tested sorbents were capable of cleaning up maltooligosaccharides from the reaction mixtures to some extent after optimization of the solid-phase extraction procedure (51.9%-98.9% recovery). The best-rated amide-based sorbent was used to process the sample of N-linked glycans enzymatically released from ribonuclease B.

Combination of a solid phase extraction and a two-dimensional LC-UV method for the analysis of vitamin D3 and its isomers in olive oil

The current HPLC methods for the quantification of vitamin D3 (VitD3) and its two isomers previtamin D3 (PreVitD3) and trans-vitamin D3 (trans-VitD3) in olive oil preparations present some limitations mainly due to peak overlapping of the oily matrix components with the compounds of interest. The use of two-dimensional liquid chromatography (2D-LC) with different retention mechanism can reach higher resolving power thus allowing the analysis of complex samples.The present paper proposes a new alternative method including a solid phase extraction sample preparation step and a two-dimensional liquid chromatographic analysis using routine instrumentation, fitting the needs of quality assurance and quality control laboratories of pharmaceutical companies. The extraction protocol was demonstrated to provide a clean-up of the sample and a quantitative recovery of the species of interest. The 2D method proved its suitability in the isolation of vitamins from oil components in the first dimension and the separation and quantification of the analytes in the second dimension thanks to the orthogonal selectivities of phenyl and porous graphitic carbon (PGC) stationary phases.The method was validated following ICH guidelines and possesses an adequate sensitivity to quantify the impurity trans-VitD3 in pharmaceuticals considering the limits imposed by regulatory agencies. The applicability of the phenyl x PGC 2D-LC-UV method to quality control of medicinal products based on VitD3 in olive oil was confirmed by the successful quantification of vitamins in olive oil formulations.

Using Liquid Chromatography-Isotope Ratio Mass Spectrometry for Detection of Economically Motivated Adulteration of Maple Syrup.

Maple syrup is a sought-after commodity, and used as a condiment and a sweetener. Also, it is an active target of economically motivated adulteration (EMA), similar to other foods such as lemon juice and honey. This study is aimed to detect low cost sugar adulteration in maple syrup via an internal standard method using malic acid through solid-phase extraction (SPE) and LC with isotope ratio mass spectrometric detection (LC-IRMS). In this work, an optimized SPE sample preparation procedure was used for the isolation of organic acids from maple syrup. Using LC-IRMS, malic acid was separated from other organic acids and the δ13C value of malic acid was determined. Eleven maple syrup samples, domestic or imported from Canada, were evaluated for 13C/12C ratios (δ13C values) using combustion module-cavity ring down spectrometry (CM-CRDS) and compared to the δ13C values obtained from well-established elemental analyzer-isotope ratio mass spectrometry (EA-IRMS) methods. The δ13C values of isolated malic acid analyzed by SPE-LC-IRMS were used as internal standards and compared to the δ13C values of bulk maple syrup; difference (δ13Csugars - δ13Cmalic acid) values greater than 3.6‰ are indicative of low-cost sugar adulteration. Overall, the results obtained from SPE-LC-IRMS provided a faster, novel analysis approach for determining low-cost sugar adulteration in maple syrup for regulatory purposes. This method also provided lower detectable limits of adulteration versus current literature reports using bulk analysis and comparable detection limits to Tremblay and co-workers who utilized an internal standard method. SPE-LC-IRMS is a robust method that can be used for detecting adulteration in maple syrup samples for regulatory purposes. SPE-LC-IRMS is a faster, novel analysis approach for determining C4 adulteration in maple syrup with lower detection limits.

Development of new analytical methods for the quantification of organic acids, chlorogenic acids and caffeine in espresso coffee by using solid-phase extraction (SPE) and high-performance liquid chromatography-diode array detector (HPLC-DAD)

Acidity is an important parameter in coffee, contributing to aroma and flavor, imparting fruity notes, and improving the gloss of the coffee, making the beverage more interesting. In this study, two analytical methods were proposed to quantify the content of nine organic acids, caffeine, phenolic acids, and four chlorogenic acids in espresso coffee using an HPLC-DAD instrument. In addition, a new solid-phase extraction (SPE) sample clean-up procedure for organic acids has been optimized. The newly developed analytical methods were characterized by satisfactory recovery levels of sample clean-up procedure (41.798.6%) and good resolution of all peaks in both chromatography separations. In addition, the investigated validation parameters implied good repeatability, sensitivity and linearity. These methods were applied to espresso samples with three different roasting degrees (light, medium, and dark) of the same coffee variety (100% Arabica) to study the effects of the roasting process on the content of caffeine, organic and chlorogenic acids. The caffeine content was relatively stable to heat. The concentration of chlorogenic acids decreased due to roasting while the total organic acid content increased, with the formation of acetic and lactic acids in medium and dark roasting. Therefore, these new approaches can be considered as reference methods for the determination of carboxylic acids in coffee.

Investigating analyte breakthrough under non-linear isotherm conditions during solid phase extraction facilitated by non-targeted analysis with comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry

Solid phase extraction (SPE) sample preparation for the analysis of complex organic mixtures is often applied assuming all analytes of interest will preconcentrate on the stationary phase. This assumption ignores the reality that extraction is a dynamic interactive process and a diverse range of affinities for the stationary phase will result in equally diverse breakthrough volumes due to competitive sorption processes. To study this dynamic interactive process, and further to take advantage of it, we extracted a JP-8 jet fuel spiked with 40 ppm of a polar compound mix with silica and alumina SPE cartridges and analyzed sequential extracted fractions of the fuel to both assess the shifting chemical landscape present in the extraction and the impact of both SPE stationary phases on this process. Tile-based 1v1 comparative analysis (a recently reported extension of tile-based Fisher ratio analysis) was used to discover the (polar) compounds whose concentrations change between extracted fractions, discovering 21 compounds extracted with silica and 27 compounds extracted with alumina with at least a 2-fold change in concentration from the neat sample relative to the first 1 mL pass fraction sample. These compounds were quantified in each fraction to construct concentration ratio profiles, defined as the concentration ratio for a given SPE fraction per analyte compound relative to the analyte concentration in the neat fuel, for which the extraction behavior for each analyte could be assessed. These analyte compounds were found to breakthrough at different rates, with some analytes remaining on the column indefinitely (until extracted with a subsequent polar solvent) and other analytes eluting before the extraction is complete. Furthermore, in a comparison of the effect of selected stationary phase, alumina was found to retain oxygen-containing phenolic compounds to a greater extent than silica. Principal component analysis (PCA) was used to analyze the concentration ratio profiles of the various trace analytes in the JP8 fuel (phenols, indoles, etc.) in the context of their stationary phase affinity (silica or alumina) and competitive sorption behavior.

Screening and quantification of pesticide residues in ciders by liquid chromatography-high resolution mass spectrometry

The present study aimed to apply a multi-residue method for the screening and quantification of pesticide residues in ciders, low alcoholic beverages made by fermentation of apple juice. Twenty bottled craft cider samples purchased from the Czech market were analysed for pesticide residues. The residues of pesticides were extracted from samples using the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) procedure in combination with additional solid-phase extraction (SPE) sample clean-up to achieve the lowest detection limit possible. In this study, targeted screening of pesticide residues in the samples was performed with the Q-Orbitrap mass spectrometry instrument. We identified 18 pesticides in cider samples analysed by screening method using an accurate-mass database of about 500 pesticide compounds, including their retention times, empirical formulas, and characteristic fragments. Additionally, liquid chromatography with high-resolution tandem mass spectrometer (LC-HRMS/MS) was used for re-analysis of positive findings of pesticides in samples and allowed to quantify compounds of interest at 0.2 µg L–1 concentration level. The monitoring scheme was applied to the set of craft ciders, and the results revealed the presence of pesticide residues in most of the samples at trace levels ranging from 0.5 to 5 µg L–1 and rarely at a level higher than 10 µg L–1.

Quantification of 37 glucocorticoids in chicken muscle by UHPLC-Q-Orbitrap-MS with parallel reaction monitoring.

The quantification capability of high-resolution mass spectrometry (HRMS) has received increasing interest from analysts. In this study, we present a method for analyzing 37 glucocorticoids in chicken muscle using UHPLC-Q-Orbitrap MS with parallel reaction monitoring (PRM). The analytes were extracted using acetonitrile (ACN) containing 0.1% formic acid and subjected to commercial PRiME HLB solid-phase extraction (SPE) cartridge clean-up. Under optimized conditions, the analytes were separated on an analytical column and subsequently detected using a high-resolution hybrid quadrupole/Orbitrap mass spectrometer coupled with PRM scan mode. The Q-Orbitrap with PRM exhibited remarkable sensitivity, with limits of quantification (LOQs) ranging from 0.08 μg kg-1 to 7.59 μg kg-1. To validate the method, we conducted intra- and inter-day tests using a blank matrix sample at different spiking levels. The achieved results demonstrated satisfactory recovery values (74.1-97.5%) and precise results (RSDs < 15%) for all the studied analytes. In application, we found dexamethasone with 6.5 μg kg-1 and fluorometholone with 3.9 μg kg-1 in two chicken samples. These findings suggest that the UHPLC-Q-Orbitrap system, in conjunction with the SPE sample preparation method, has great potential as a routine quantification approach for multiple glucocorticoid residues in chicken samples.

Progress in sample pretreatment and detection methods of hexabromocyclododecanes

作为一种常见的溴代阻燃剂,六溴环十二烷(HBCDs)因具备持久性、长距离迁移性、生物蓄积性和高毒性,于2013年被列入《斯德哥尔摩公约》。因此,环境样品中HBCDs污染水平的准确分析和严格控制对完善环境监管长效机制至关重要。然而,实际样品中HBCDs的定性定量分析正面临着基质复杂、目标物含量低等问题。尤其,HBCDs在高温环境及特定有机溶剂中易降解,会产生异构体,提高了分析难度。该综述简述了HBCDs的理化性质、毒性危害和标准限制,重点围绕不同基质中HBCDs的样品前处理和仪器检测两方面进行了总结。论文内容引用2000~2022年的70余篇源于科学引文索引(SCI)与中文核心期刊中的相关论文。总结归纳了固体和液体样品中HBCDs分析的前处理技术,包括索式提取、超声辅助萃取、加速溶剂萃取、超临界流体萃取、液液萃取、分散液液微萃取、固相萃取、分散固相萃取和固相微萃取等,介绍了气相色谱、液相色谱和色谱-质谱联用技术等仪器检测方法在HBCDs分析中的应用。通过综述近期相关研究,侧面表明HBCDs的分析方法研究发展迅速,但也面临一些挑战,如样品前处理步骤繁琐、耗时长、样品量和有机溶剂用量大等问题。最后,对新型样品前处理技术在HBCDs分析中的应用进行了展望。

ATP-Responsive Strand Displacement Coupling with DNA Origami/AuNPs Strategy for the Determination of Microcystin-LR Using Surface-Enhanced Raman Spectroscopy.

The DNA origami-mediated self-assembly strategy has emerged as a powerful tool in surface-enhanced Raman spectroscopy (SERS). However, these self-assembly approaches typically do not possess high detection specificity. Herein, a novel strategy based on adenosine triphosphate (ATP)-responsive strand displacement (ARSD) coupling with DNA origami/AuNPs for SERS analysis of microcystin-LR (MC-LR) is presented. In the presence of MC-LR and ATP molecules, nucleic acid sensing structures fabricated with anti-MC-LR aptamer (T1) and ATP aptamer (T2) were triggered to release the remaining ATP. In addition, DNA origami-assisted assembly results in the formation of homogeneous plasmonic nanostructures for Raman enhancement via strong plasmonic coupling. After the binding in the gaps of functionalized DNA origami/AuNPs, the Raman shift of the ATP molecules becomes detectable, leading to increased SERS intensity in 734 cm-1. A linear response to MC-LR was obtained in the concentration range of 1.56-50 μg·L-1, and the limit of detection (LOD) was 0.29 μg·L-1. Combined with the solid-phase extraction sample pretreatment for extraction and 10-fold concentration, this proposed method was successfully used to detect MC-LR type in real lake-water samples with good recoveries of 98.4-116% and relative standard deviations of 1.9-6.7%. Furthermore, for the detection of MC-LR in contaminated lake-water samples, the results of the developed method and ultrahigh-performance liquid chromatography-tandem mass spectrometry were found to be in agreement with relative errors between -12 and 2.4%. The proposed strategy provides a sensitive recognition and signal amplification platform for trace MC-LR analysis as well as innovative nucleic acid sensing structures for toxin analysis more generally.

Metode Analisis Paracetamol (Acetaminophen) dalam Darah, Plasma, Dan Serum Manusia

Paracetamol (Acetaminophen) is one of the drugs most often prescribed to patients, ranging from children to the elderly, as a pain reliever by inhibiting prostaglandin synthesis in the central nervous system. Paracetamol has a broad therapeutic index with an adult dose of 500-1000 mg each time, with an interval of 4-6 hours. The review article aims to compare the analysis and sample preparation methods used to detect paracetamol in human blood, plasma, and serum. In compiling this article, the search method for research journals via the internet was used with Google. The results obtained showed that the detection of paracetamol in blood and serum was analyzed using the Gas Chromatography-Mass Spectrometry (GC-MS) with SPE (Solid Phase Extraction) sample preparation method while in plasma it was analyzed using several methods, namely Liquid Chromatography-Mass Spectrometry (LC-MS), High-Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS), and Ultra-High-Performance Liquid Chromatography-Mass Spectrometry (UHPLC-MS) with protein precipitation and liquid-liquid extraction sample preparation methods. Among the four methods, the HPLC-MS method is considered fast, selective, and sensitive to analyzing paracetamol

Quality Control of Emerging Contaminants in Marine Aquaculture Systems by Spot Sampling-Optimized Solid Phase Extraction and Passive Sampling

The presence of organic pollutants such as pesticides and pharmaceuticals in the aquatic environment, and especially in regions where fish farms are installed, is a matter of major importance due to their possible risks to ecosystems and public health. The necessity of their detection leads to the development of sensitive, reliable, economical and environmentally friendly analytical methods for controlling their residue in various environmental substrates. In the present work, a solid-phase extraction method was developed, optimized and validated for the analysis of 7 pesticides and 25 pharmaceuticals in seawater using LC-HR-LTQ/Orbitrap-MS. The method was then applied in seawater samples collected from an aquaculture farm located in the Ionian Sea, Greece, in order to evaluate environmental pollution levels. None of the pesticides were detected, while paracetamol was the only pharmaceutical compound that was found (at trace levels). At the same time, passive sampling was conducted as an alternative screening technique, showing the presence of contaminants that were not detected with spot sampling. Among them, irgarol was detected and as far as pharmaceuticals is concerned, trimethoprim and sulfadiazine were found; however, all positive findings were at the very low ppt levels posing no threat to the aquatic environment.

Elevated Urinary Biomarkers of Oxidative Damage in Photocopier Operators following Acute and Chronic Exposures.

Inhalation exposures to nanoparticles (NPs) from printers and photocopiers have been associated with upper airway and systemic inflammation, increased blood pressure, and cases of autoimmune and respiratory disorders. In this study we investigate oxidative stress induced by exposures to copier-emitted nanoparticles using a panel of urinary oxidative stress (OS) biomarkers representing DNA damage (8-hydroxydeoxyguanosine, 8-OHdG; 8-hydroxyguanosine, 8-OHG; 5-hydroxymethyl uracil 5-OHMeU), lipid peroxidation (8-isoprostane; 4-hydroxynonenal, HNE), and protein oxidation biomarkers (o-tyrosine, 3-chlorotyrosine, and 3-nitrotyrosine) under conditions of acute (single 6 h exposure, 9 volunteers, 110 urine samples) and chronic exposures (6 workers, 11 controls, 81 urine samples). Urinary biomarkers were quantified with liquid chromatography–tandem mass spectrometry after solid phase extraction sample cleanup. 8-OHdG, 8-OHG, 8-isoprostane, and HNE were significantly elevated in both the acute and chronic exposure study participants relative to the controls. In the acute exposure study, the geometric mean ratios post-/pre-exposure were 1.42, 1.10, 2.0, and 2.25, respectively. Urinary 8-OHG and HNE increased with time to at least 36 h post-exposure (post-/pre-exposure GM ratios increased to 3.94 and 2.33, respectively), suggesting slower generation and/or urinary excretion kinetics for these biomarkers. In chronically exposed operators, the GM ratios of urinary biomarkers relative to controls ranged from 1.52 to 2.94, depending on the biomarker. O-Tyrosine and 5-OHMeU biomarkers were not significantly different from the controls. 3-chlorotyrosine and 3-nitrotyrosine were not detected in the urine samples. We conclude that NPs from photocopiers induce systemic oxidative stress by damaging DNA, RNA, and lipids. Urinary levels of 8-OHdG, 8-OHG, HNE, and 8-isoprostane were orders of magnitude higher than in nanocomposite processing workers, comparable to nano titanium dioxide and fiberglass manufacturing workers, but much lower than in shipyard welding and carbon nanotube synthesis workers. Biomarkers 8-OHdG, 8-OHG, 8-isoprostane, and HNE appear to be more sensitive and robust urinary biomarkers for monitoring oxidative stress to NPs from photocopiers.

A novel solid phase extraction sample preparation method for sensitively determining doxepin and N-nordoxepin in human plasma and its application in a bioequivalence study in healthy Chinese volunteers.

Doxepin, a tricyclic antidepressant (TCA), is widely used in the treatment of depressive disorder and anxiety. There are some liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods that have been reported for detecting doxepin, but inadequacies in recovery and cumbersome sample preparation obstruct the pharmacokinetics study. Therefore, we aimed to develop and validate a rapid sample preparation method based on solid-phase extraction (SPE) for the precise quantification of doxepin and its metabolites. Chromatography separation was performed on a Waters ACQUITY UPLC BEH C18 column (2.1 × 100 mm, 1.7 μm) and a mobile phase consisting of 70% of mobile phase A (0.1% formic acid and 10 mM ammonium formate) and 30% mobile phase B (0.1% formic acid in acetonitrile) at a flow rate of 0.4 mL min-1 in the step gradient elution conditions. The lower limits of quantification for doxepin and N-nordoxepin were 4 pg mL-1 and 2 pg mL-1, respectively. This method was validated with satisfactory results including good precision and accuracy. A rapid, sensitive, and specific LC-MS/MS method was developed and validated for the determination of doxepin in human plasma. This method could be applied for determining doxepin and N-nordoxepin concentrations in plasma that could be useful for bioequivalence study of 3 mg doxepin.