Cleanup Method Research Articles

Membrane Sampling Separates Naphthenic Acids from Biogenic Dissolved Organic Matter for Direct Analysis by Mass Spectrometry.

Oil sands process waters can release toxic naphthenic acids (NAs) into aquatic environments. Analytical techniques for NAs are challenged by sample complexity and interference from naturally occurring dissolved organic matter (DOM). Herein, we report the use of a poly(dimethylsiloxane) (PDMS) polymer membrane for the on-line separation of NAs from DOM and use direct infusion electrospray ionization mass spectrometry to yield meaningful qualitative and quantitative information with minimal sample cleanup. We compare the composition of membrane-permeable species from natural waters fortified with a commercial NA mixture to those derived from weak anion exchange solid-phase extraction (SPE) using high-resolution mass spectrometry. The results show that SPE retains a wide range of carboxylic acids, including biogenic DOM, while permeation through PDMS was selective for petrogenic classically defined NAs (CnH2n+zO2). A series of model compounds (log Kow ∼1–7) were used to characterize the perm-selectivity and reveal the separation is based on hydrophobicity. This convenient sample cleanup method is selective for the O2 class of NAs and can be used prior to conventional analysis or as an on-line analytical strategy when coupled directly to mass spectrometry.

Chiral Pesticides with Asymmetric Sulfur: Extraction, Separation, and Determination in Different Environmental Matrices

Chiral pesticides with S atoms as asymmetric centers are gaining great importance in the search for new pesticides with new modes of action. As for the rest of the chiral pesticides, the determination of the stereoisomers separately has become crucial in the environmental risks assessment of these pesticides. Therefore, the development of suitable extraction and clean-up methods as well as efficient stereoselective analytical techniques for stereoisomers determination in environmental samples is essential. Currently, liquid/solid phase extraction, microextraction, and QuEChERS-based methods are most commonly used to obtain chiral pesticides from environmental samples. Gas, liquid, and supercritical fluid chromatography together with capillary electrophoresis techniques are the most important for the determination of the stereoisomers of chiral pesticides containing S atoms in its structure. In this study, all these techniques are briefly reviewed, and the advantages and disadvantages of each are discussed.

Simultaneous determination of trichothecene mycotoxins in cereals by LC-MS/MS.

This study was designed to determine the residual trichothecene mycotoxins in cereal samples. The optimal solvent for extraction was 84% (v/v) aqueous acetonitrile with 1% (v/v) formic acid. The best performing clean-up method was dispersive-solid phase with a mixture octadecyl silica and primary-secondary amine. The recoveries for the studied mycotoxins ranged from 83.3 to 92.8%. The methodology was successfully applied for monitoring 100 cereal samples obtained from a Korean market. The bean sample were found to be co-contamination with deoxynivalenol and HT-2 toxin. Deoxynivalenol possessed the highest detection freauency (4/100) and amount (727.38µg/kg) among the trichothecene mycotoxins. The hazard index was less than 1.0 for all the observed mycotoxins in all cereal samples except one white rice sample (1.2681). This results indicated that periodic risk assessments of trichothecene mycotoxin through cereal intake are necessary for the health and safety.

Qualitative Screening of Amphetamine- and Ketamine-Type Abuse Drugs in Urine Employing Dual Mode Extraction Column by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS-MS).

This manuscript reported a fast and rapid qualitative screening method for abuse drugs in urine by liquid chromatography-tandem mass spectrometry (LC-MS-MS). The scope of the abuse drugs under investigation included methamphetamine (MA), amphetamine (AMP), methylenedioxymethamphetamine (MDMA), methylenedioxyamphetamine (MDA), paramethoxymethamphetamine (PMMA), ephedrine, pseudoephedrine, ketamine (KET), deschloroketamine (DCK), 2-fluorodeschloroketamine (2 F-DCK) and deschloro-N-ethylketamine (2-oxo-PCE). The method employed a dual mode extraction (DME) column as a novel clean-up method for the urine matrix. To an aliquot of 0.2 mL urine, internal standards (ISTDs) and 0.4 mL of acidified methanol were added. After vortex and centrifugation, the supernatant was passed through a DME column before LC-MS-MS analysis. Chromatographic separation was achieved with a C18 column by gradient elution. The limits of detection (LODs) for MA, AMP, MDMA, MDA and PMMA were 3 ng/mL, whereas those for ephedrine and pseudoephedrine were 10 ng/mL and those for KET, DCK, 2 F-DCK and 2-oxo-PCE were 1 ng/mL. The matrix effects ranged from -12% to 7% (%CV from 4% to 19%). This method is fit for the intended purpose for forensic toxicology, as well as for forensic analysis of drugs facilitating sexual assault and other criminal acts.

Development of an Analytical Method for Kasugamycin Residue in Herbal Medicine, <i>Achyranthes japonica</i> Nakai

This study developed a suitable analytical method for kasugamycin residues in Achyranthes japonica using LC/MS/MS equipped with an amide column for polar substances. Extraction and cleanup processes were done at pH 4.5–5. Purification efficiency was assessed and confirmed step by step by selecting silica, hydrophilic-lipophilic balance (HLB), strong cation exchange (SCX), and double (HLB and SCX) cleanup SPE cartridges. The results indicated that silica SPE cartridge exhibited overloading tendency, while HLB SPE cartridge had low cleaning efficiency. Among SPE cartridges used, double cleanup and SCX were found sufficient with respective matrix effects of –15% and +14%, respectively. The LOD and LOQ were 0.008 ng and 0.04 mg/kg, respectively. The correlation coefficient (R2) was higher than 0.99, recovery rate ranges were 86.3–97.2%, and the RSD was below 8.8%. All methods are consistent with the Codex guidelines criteria. This study developed an appropriate LC/MS/MS analytical method for kasugamycin residue analysis in A. japonica with optimized, efficient extraction and purification conditions using a single SCX SPE cartridge, which is simple and time-efficient. In addition, the HLB and SCX SPE cartridges of the double cleanup methods were identified as primary methods that can be applied for the cleanup of other medicinal herbs.

Automated multi-plug filtration cleanup method for analysis of 48 pesticide residues in green tea using liquid chromatography-tandem mass spectrometry

An automated multi-plug filtration cleanup (m-PFC) method, based on QuEChERS extraction was developed for the analysis of 48 pesticides in green tea. The carboxyl functionalized multi-walled carbon nanotubes (MWCNTs-COOH) were firstly packed in m-PFC columns and functioned as promising sorbents with better clean-up capability. The different parameters of automated m-PFC equipment and extraction conditions were optimized. The automated method integrated cleanup and filtration (through filter membrane) procedure into a single run before injected to the detection instrument. Comparison to d-SPE and manual m-PFC method, the automated method could handle a batch of samples simultaneously with better purification effect. Acceptable recoveries at three concentration levels from 71% to 114% were obtained (except carbendazim and bifenazate) with relative standard deviations lower than 18%. The proposed automated m-PFC method offered a great compromise between rapidity, convenience and efficiency. It was successfully applied for market monitoring of pesticide residues with robust analyze data. • Automated m-PFC method for analysis of 48 pesticides in green tea. • Functionalized MWCNTs were mixed with other sorbents to assess cleanup performance. • Extraction and automated m-PFC process were optimized by recovery and matrix effect. • Method validation showed superior purification efficiency and robust analysis data. • The automated method can handle a batch of real sample in routine pesticide analysis.

Analysis of pesticide residues in fruits and vegetables using gas chromatography-mass spectrometry: a case from West Omo and Bench-Sheko Zone, Southwest Ethiopia

ABSTRACT Uncontrolled use of pesticides could result in contamination of air, water, food, and ecosystems. This study aimed to determine pesticide residues in fruits and vegetables collected from selected farmlands of southwest Ethiopia from the end of April 2019 until mid of May 2019. The samples were extracted using a quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction and clean-up method. Quantitative analysis of four organophosphorus pesticides (OPPs) and seven organochlorine pesticides (OCPs) were conducted using gas chromatography-mass spectrometry. All the fruit and vegetable samples obtained from all sampling sites were contaminated with one or more pesticide residues. Chloroflurenol-methyl was the most predominantly detected OPPs residue in all crop samples obtained from different sampling sites, with a maximum concentration of 0.402 mg kg−1 in potato samples obtained from the Gurafarda site and a minimum value of 0.049 mg kg−1 in onion samples obtained from the South Bench site. Dibutyl chlorendate was the predominant OCPs in all samples, with the minimum value of 0.498 mg kg−1, which was detected in tomato samples collected from the Jamo site, and the maximum concentration of 1.003 mg kg−1 detected in pineapple samples obtained from the North Bench site. Dimethoate concentrations in tomato samples (0.045–0.084 mg kg−1) were above the maximum residue limits (MRLs) established by the European Union (EU) guidelines (0.01 mg kg−1) but were below the MRLs established by Codex Alimentarius Commission (CAC) guidelines (0.5 mg kg−1). Relatively high residue concentrations of dibutyl chlorendate and chloroflurenol-methyl were detected in all the samples obtained from all sampling sites. There is widespread use of pesticides for agriculture by the producers in the study area and there is a need for the regular monitoring of pesticide residues.

Protein Extraction and Sample Preparation Methods for Shotgun Proteomics with Central Nervous System Cells and Brain Tissue.

Shotgun proteomics based in mass spectrometry has been extensively utilized to investigate biological samples for basic and applied research in the clinical field to elucidate changes in the molecular mechanisms caused by diseases. There is still a great lack of information about the molecular mechanisms and the origins of most brain disorders, which makes shotgun proteomics an interesting tool in the study of these diseases. A wide range of samples can be used to study such diseases, such as cerebrospinal fluid, central nervous system cells, and brain tissue via postmortem analysis. As such, different protein extraction methods must be applied to achieve the best results for each sample type. The lysis buffer, digestion protocol, and peptide purification steps chosen prior to liquid chromatography-mass spectrometry analyses are essential to obtain reliable proteomic datasets. For this reason, the availability of a list with a variety of methods and a description of the pros and cons for each one has been compiled and elaborated upon. This review presents several methods for protein extraction, protein digestion, and sample cleanup with a focus on shotgun proteomics via mass spectrometry and a further focus on studying brain disorders.

A New Method for the Simultaneous Clean-Up and Analysis of Perfluorinated Alkyl Acids in Environmental Samples, Using Two Dimensional Lc-Ms/Ms

A New Method for the Simultaneous Clean-Up and Analysis of Perfluorinated Alkyl Acids in Environmental Samples, Using Two Dimensional Lc-Ms/Ms

A Feasibility Study of Natural Attenuation as a Viable Cleanup Method for Heavy Oil Spills

The constant focus of the public and media on oil spill pollution in the environment has led to a forced improvement in its clean-up process. But these methods are not as effective and efficient as society and the environment requires them to be. One of the major reasons for this is that an oil spill does not contain uniform distribution of the oil over an area, neither are the microorganisms present evenly distributed in the environment. However, when it is not possible for fiscal and any technical reasons to bring about ecosystem restoration, the obvious strategy is to prevent the discharge of pollutants. When this is not possible and crude oil (or heavy oil) has already been introduced to the environment, there is the potential for the Earth to heal itself and introduce balance over time. What is necessary as a society is to harness these natural methods and ensure that oil spills are contained in the shortest time possible.

Paper-based sample processing for the fast and direct MS analysis of multiple analytes from serum samples.

Amino acids are closely related to human health, and their rapid determination is important for the rapid diagnosis, timely treatment, and assessment of serious diseases. In this work, we propose a novel paper-based sample-processing device combined with isotope-dilution MS for the fast analysis of 11 amino acids from blood samples. By using an isoelectric focusing electrokinetic separation method, without the aid of carrier ampholytes and the addition of inhibitors, this approach uses only the characteristic of the isoelectric point of the target amino acids to achieve separation and purification from other coexisting components in the medium; it can meet the requirements for mass spectrometry detection. Driven by a DC voltage, a stable and sharp pH gradient (pH 3-10.5 over 5 mm) can be established in a glass-fiber paper-based fluidic channel with a MS-friendly electrolyte. Amphoteric species can be well separated from the complex blood matrix and concentrated into a narrow band in the channel within 2 min, which is 20 times faster than a commercial kit method. The method can be applied to both liquid and dry spot samples, and the cleaned sample band can be simply dissolved for direct IDMS detection in ESI MRM mode. This method is a promising strategy for the rapid MS-based detection of amino acids from serum without pre-separation via liquid chromatography.

A multi-plug filtration (m-PFC) cleanup method based on carboxylic multi-walled carbon nanotubes for the detection of 14 perfluorinated compounds and dietary risk assessment of chicken, beef, and mutton collected from Shanghai markets

Dietary intake is a major pathway of human exposure to perfluorinated compounds (PFCs). Livestock and poultry meats (chicken, beef, mutton) account for a significant proportion of dietary consumption in China, and thus it is crucial to investigate the levels and composition profiles of PFCs in consumer meats to assess and mitigate potential health risks. However, rapid and simple analytical methods for such investigations are lacking. This study addresses this shortcoming by developing a rapid filtration clean-up method using carboxylic multi-walled carbon nanotubes (CMWCNTs) for the detection of 14 PFCs. Good linearities (R2 > 0.99) were obtained for all 14 PFCs in chicken, beef, and mutton. Recoveries ranged from 65 to 145% (except perfluorotetradecanoic acid, PFTeDA) with relative standard deviations (RSDs) lower than 16%. Method limits of detection (LODs) were between 0.12 and 0.83 ng g−1d.w. Subsequently, this method was applied for the analysis of 46 livestock and poultry meat samples collected from markets in Shanghai. PFCs were detected in all samples with total concentrations of 1.61–4.27 ng g−1 wet weight (w.w) in chicken, 1.51–5.56 ng g−1 w.w in beef and 1.61–8.15 ng g−1 w.w in mutton. Perfluorooctanoic acid (PFOA) and perfluorobutanoic acid (PFBA) were the predominant compounds in these samples and accounted for over 92% of ΣPFCs. For regulated compounds such as PFOA, risk quotients (RQs) were determined to be much lower than 1. This suggests that chicken, beef, and mutton from Shanghai market pose very low PFC exposure risk to residents. However, high detection frequency of the unregulated PFBA demands further investigation of short-chain PFCs in consumer meats.

A critical review of advanced nanotechnology and hybrid membrane based water recycling, reuse, and wastewater treatment processes

One of the modern challenges is to provide clean and affordable drinking water. Water scarcity is caused by the growing population in the world and pollutants contaminate all remaining water sources. Innovative water treatment solutions have been provided by nanotechnology. Microorganisms, organic suspensions, and inorganic heavy metal ions, among other things, are common water contaminants. Since antiquity, a wide range of water clean-up methods have been employed to address this issue. Breakthroughs in water purification procedures have occurred during the previous four decades, with the most significant one being the use of nanomaterials and nanomembranes. Nanoparticles and nanomembranes (polymeric membranes) have recently been used in engineered materials (TiO2, ZnO, CuO, Ag, CNT's and mixed oxide nanoparticles, for example). Engineered nanomembranes, nanocomposites and nanoparticles have been used in this review article's discussion of water purification technologies. The review also discusses the risk and solutions of using nanoparticles and nanocomposites in the future.

Utilizing a Rapid Multi-Plug Filtration Cleanup Method for 72 Pesticide Residues in Grape Wines Followed by Detection with Gas Chromatography Tandem Mass Spectrometry

A convenient and fast multi-residue method for the efficient identification and quantification of 72 pesticides belonging to different chemical classes in red and white grape wines has been developed. The analysis was based on gas chromatography tandem quadrupole mass spectrometric determination (GC–MS/MS). The optimization strategy involved the selection of the amount of multi-walled carbon nanotubes (MWCNTs) and the number of cleanup procedure cycles for multi-plug filtration cleanup (m-PFC) to achieve ideal recoveries and reduce the sample matrix compounds in the final extracts. The optimized procedure obtained consistent recoveries between 70.2 and 108.8% (70.2 and 108.8% for white wine, and 72.3 and 108.4% for red wine), with relative standard deviations (RSDs) that were generally lower than 9.2% at the three spiking levels of 0.01, 0.05 and 0.1 mg/kg. The linearity was studied in the range between 0.002 and 0.1 mg/kg using pesticide standards prepared both in pure solvent and in the presence of the matrix, showing coefficients of determination (R2) higher than 0.9495 for all the pesticides. To improve accuracy, matrix-matched calibration curves were used for calculating the quantification results. Finally, the method was used successfully for detecting pesticide residues in commercial grape wines.

Easy and effective analytical method of carbendazim, dimethomorph, and fenoxanil from Protaetia brevitarsis seulensis using LC-MS/MS.

Traditionally in Korea, Protaetia brevitarsis seulensis (white-spotted flower chafer) has been used as a medicine, and recently has attracted increased attention due to its antithrombotic efficacy. Some of spent mushroom compost or fermented oak sawdust, a feedstock for P. brevitarsis, were contaminated with three fungicides, carbendazim, dimethomorph, and fenoxanil, which could be transferred to the insect. This study was aimed to optimize a simple extraction method combined with liquid chromatography tandem mass spectrometry and apply it to the real samples. After the pulverized samples (5 g) were extracted with acetonitrile (10 mL) and formic acid (100 μL), fat and lipids in the samples were slowly precipitated at -20°C for 24 hours. After eight different clean-up methods were investigated, the mixture of 150 mg MgSO4/25 mg PSA/25 mg C18 was selected due to optimal recovery of the target compounds. Recovery (77.9%‒80.8% for carbendazim, 111.2%‒116.7% for dimethomorph, and 111.9%‒112.5% for fenoxanil) was achieved with reasonable relative standard deviation (<5.5%) The analytical method developed in this study was used to analyze three compounds in the 24 insect samples donated by the insect farm owners but no target compounds were detected. These results can provide important data for establishing the pesticide safety standards for P. brevitarsis before the medical applications.

A Combination of Chromatography with Tandem Mass Spectrometry Systems (UPLC-MS/MS and GC-MS/MS), Modified QuEChERS Extraction and Mixed-Mode SPE Clean-Up Method for the Analysis of 656 Pesticide Residues in Rice.

The emerging ungovernable application of pesticides in rice farming has attracted public concerns as these hazardous chemicals leave long-lasting environmental impacts and cause severe health effects. Here, an optimized analytical method was proposed for the measurement of 656 pesticide residues in rice samples collected in Vietnam. We utilized chromatography with tandem mass spectrometry systems (UPLC-MS/MS and GC-MS/MS) combined with a modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction method and adopted a mixed-mode SPE clean-up method for the analysis. The results showed that a total of 341 and 315 compounds were determined by UPLC- and GC-MS/MS, respectively. Usage of 10 mL MeCN, 5 mL H2O and 1% glacial acetic acid as extraction solvent outperformed other mixtures in purifying the analytes from the sample matrix. Besides, pressure swing adsorption connected to a C18 cartridge with C18 placed on top exhibited remarkably more extracted compounds of high recovery which resulted in 299 and 318 compounds with recovery ranging from 70 to 120% in GC- and UPLC-MS/MS, respectively. Our optimized protocols also resulted in maximal limits of quantification of 10 μg Kg−1 in both MS methods with repeatability and reproducibility less than 20%. Application of validated method on 20 rice samples collected in Hanoi, Vietnam showed that 14 samples were contaminated with at least one pesticide, and insecticide was the most detected group. Overall, the compliance of all method validation parameters to SANTE/12682/2019 Guideline demonstrates that this protocol can be employed for the effective management of Vietnam’s rice in accordance with international requirements.

Assessment of Citrinin in Spices and Infant Cereals Using Immunoaffinity Column Clean-Up with HPLC-Fluorescence Detection.

Historically, the analysis of citrinin has mainly been performed on cereals such as red yeast rice; however, in recent years, more complex and abnormal commodities such as spices and infant foods are becoming more widely assessed. The aim of this study was to develop and validate clean-up methods for spices and cereal-based infant foods using a citrinin immunoaffinity column before HPLC analysis with fluorescence detection. Each method developed was validated with a representative matrix, spiked at various citrinin concentrations, based around European Union (EU) regulations set for ochratoxin A (OTA), with recoveries >80% and % RSD < 9% in all cases. The limit of detection (LOD) and the limit of quantification (LOQ) were established at 1 and 3 µg/kg for spices and 0.1 and 0.25 µg/kg for infant cereals, respectively. These methods were then tested across a variety of spices and infant food products to establish efficacy with high recoveries >75% and % RSD < 5% across all matrices assessed. Therefore, these methods proved suitable for providing effective clean-up of spices and infant cereals, enabling reliable quantification of citrinin detected. Samples such as nutmeg and infant multigrain porridge had higher levels of citrinin contamination than anticipated, indicating that citrinin could be a concern for public health. This highlighted the need for close monitoring of citrinin contamination in these commodities, which may become regulated in the future.

Organochlorine pesticide residues in raw and grilled freshwater fish (Oreochromis niloticus) collected from various locations along the Nile basin in Egypt.

The current study aimed to assess meat quality of samples of Nile tilapia fish (Oreochromis niloticus), along with examining organochlorine pesticide (OCP) residues in these samples and their potential risks to humans. About 55 samples were collected from eleven sites on the Nile River in Egypt: Damietta, El-Behera, El-Dakahlia, Kafrelsheikh, El-Gharbia, El-Menoufia, Cairo, El-Giza, El-Fayoum, El-Menia, and Aswan Governorates. Fish samples were analyzed fresh and grilled for meat quality characteristics and the presence of OCP residues using the QuEChERS method for extraction and cleanup accompanied by detection using GC-MS (gas chromatography-mass spectrometry) system. Then, risk hazards of OCP residues were calculated. Results showed that all quality criteria of raw and cooked meat samples were within the permissible levels set by the Egyptian Organization for Standardization and Quality (EOS). The detected residues of OCPs in fresh samples were hexachlorocyclohexanes (α-HCH, β-HCH, and δ-HCH), heptachlor, heptachlor epoxide, aldrin, dieldrin, endrin aldehyde, endosulfan, and p,p'-DDE. Endrin aldehyde was detected in all tested sites, while heptachlor epoxide was found in eight (73%) out of the 11 tested locations. After grilling, aldrin, heptachlor epoxide, endosulfan, and endrin aldehyde compounds were found in fish meat. Cooking fish samples reduced the OCP residue amounts by at least 95% of detected amounts in fresh meat.

Development and Validation of QuEChERS Followed by UHPLC-ToF-MS Method for Determination of Multi-Mycotoxins in Pistachio Nuts.

Pistachios are one of the types of tree nut fruits with the highest mycotoxin contamination, especially of aflatoxins, worldwide. This study developed a Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method that was followed by Ultra-High Performance Liquid Chromatography combined with Time-of-Flight Mass Spectrometry (UHPLC–ToF-MS) for the determination of mycotoxins in pistachios. Different approaches to dispersive solid phase extraction as a clean-up method for high lipid matrices were evaluated. For this, classic sorbents such as C18 (octadecyl-modified silica) and PSA (primary secondary amine), and new classes of sorbents, namely EMR-Lipid (enhanced matrix removal-lipid) and Z-Sep (modified silica gel with zirconium oxide), were used. The QuEChERS method, followed by Z-Sep d-SPE clean-up, provided the best analytical performance for aflatoxins (AFB1, AFB2, AFG1 and AFG2), ochratoxin A (OTA), zearalenone (ZEA), toxin T2 (T2) and toxin HT-2 (HT2) in pistachios. The method was validated in terms of linearity, sensitivity, repeatability, interday precision and recovery; it achieved good results according to criteria imposed by Commission Regulation (EC) no. 401/2006. The method was applied to real samples and the results show that pistachios that are available in Portuguese markets are safe from mycotoxins that are of concern to human health.

A review on oil spill clean-up using bio-sorbent materials with special emphasis on utilization of kenaf core fibers

Thousands of oil spill incidents regrettably have occurred on a daily basis around the globe. Oil spills are a form of pollution that poses major catastrophic threats to marine ecosystems. Oil spill incidents commonly occur in the middle of the ocean, and the process to remove the oil becomes a great challenge. Absorbents, due to their good oil-absorbing characteristics, are becoming more popular nowadays as one of the effective oil spill clean-up methods. Among the many types of oil absorbents, plant fibers were also being studied to remove the oil spills from the sea surface. This paper reviews factors leading to oil spills, the detrimental effect of the oil spill on the environment, the oil spill removal methods, and the application of plant fibers as oil absorbent material. The paper also will highlight the latest development on the utilization of kenaf core fibers as oil-absorbent material and the use of oil absorbed kenaf core fibers as fuel briquette by taking advantage the high calorific value of the oil spill.