Extraction Of Analytes Research Articles

Classification of produced water samples using class-oriented chemometrics and comprehensive two-dimensional gas chromatography coupled to mass spectrometry

Produced water (PW) is a type of wastewater that arises during oil and gas production. Due to its potential environmental impact, PW is one of the most closely monitored forms of wastewater in the petroleum industry. The total oil and grease (TOG) content in the water is a crucial parameter for assessing the environmental impact of PW. Traditional methods for analyzing TOG in PW can be time-consuming and may not be compatible with green chemistry principles. In this study, an alternative method for classifying PW samples is proposed using a one-class classifier (OCC) model, which has proven useful for classification problems. To achieve this goal, headspace solid-phase microextraction (HS-SPME) combined with comprehensive two-dimensional gas chromatography (GC×GC) were employed to obtain TOG profiles from PW. A series of simulated PW samples containing TOG were generated using a mixture design comprising four petrochemicals at concentrations ranging from 10 mg L-1 to 50 mg L-1. The polydimethylsiloxane (PDMS) fiber showed the most representative extraction of analytes. The optimization of the HS-SPME method was performed using a Doehlert design with two variables, and the final conditions were set at 80 °C and 70 min for extraction temperature and time, respectively. A pixel-based data approach was used to implement data-driven soft independent modeling by class analogy (DD-SIMCA). Although DD-SIMCA is a developing area in GC×GC studies, the proposed model produced outstanding results with a sensitivity of 94.3 %, specificity of 95.0 %, and accuracy of 94.5 %, considering the complex and broad compositional range of the modeled mixtures. These findings demonstrated the effectiveness of the OCC model approach in classifying PW samples according to environmental regulations.

A reverse micelle-mediated dispersive liquid-liquid microextraction coupled to high-performance liquid chromatography for the simultaneous determination of agomelatine and venlafaxine in pharmaceuticals and human plasma

An eco-friendly dispersive liquid-liquid microextraction mediated with a reverse micelle and coupled to an HPLC-DAD was developed for the simultaneous determination of venlafaxine and agomelatine in dosage forms and human plasma. All the parameters affecting the extraction efficiencies of both drugs were investigated and optimized. Under the optimal conditions, an effective analytes’ preconcentration with enrichment factors (EFs) up to 72 was achieved. The linearity of the method was established over the concentration range of 0.50−70.0 and 3.0−100.0 ng/mL for venlafaxine and agomelatine, respectively with good correlation coefficients > 0.998. The method exhibited low detection limits in the range of 0.15-0.89 ng/mL and excellent precisions expressed in %RSD < 3% with average recoveries between 95.0 to 101.0%. The proposed method was employed to analyze the targeted analytes in dosage forms and human plasma samples with favorable characteristics like excellent enrichment, high sensitivity, great accuracy, and high precision. Finally, the greenness of the developed method was assessed using three distinct metric tools, confirming the greenness of the proposed method. The findings of this research could have more general implications for the extraction of other analytes from various matrices.

Novel capsule phase microextraction - Gas chromatography - Mass spectrometry for analysis of pheniramine in a case of its fatal intoxication

In forensic toxicology, the extraction and purification of analytes from complex biological matrices heavily rely on the effectiveness of sample preparation methods. However, existing methods often face inherent challenges such as interfering substances and limited sample quantities, which can compromise the accuracy and efficiency of toxicological analyses. In the present work, for the first time, capsule phase microextraction (CPME) was implemented in forensic toxicology casework for the straightforward, affordable and sustainable extraction of the pheniramine (PHN) drug from human autopsy samples (whole blood and liver) and determined by GC-MS. A systematic investigation was conducted to optimize the extraction efficiency of CPME by examining and optimizing significant variables such as pH and volume of sample, adsorption time, desorption time and volume. The optimized method demonstrated linearity, covering a range of 0.1–10 μg mL−1 for blood samples and 0.1–10 μg g−1 for liver samples. The limit of quantification (LOQ) of the method for PHN in blood and liver samples was determined to be 0.063 μg mL−1 and 0.076 μg g−1, respectively. Repeatability and reproducibility of the method were less than 3.2% and 9.2%, respectively. The method demonstrated accuracy and recovery within the ranges of 94%–101.3%, and 67.4%–82%, respectively. The method was applied for analysis of autopsy samples from a case of fatal PHN intoxication and results were compared to those obtained using the conventional solid-phase extraction (SPE) method. Further, the competence of the proposed method has been judged by White Analytical Chemistry (WAC) RGB12 algorithm. CPME-GC-MS method demonstrates notable performance and significant stride in the domain of postmortem toxicology sample preparation. It is superior to traditional methods in several ways such as simpler, more sustainable, affordable and overcome the challenges of interfering substances and limited sample quantity.

Ultrasound-assisted three-phase hollow fiber microextraction-based method for untargeted metabolomics

Sample treatment for untargeted metabolomics is still the bottleneck of the analytical procedure, especially for complex samples like food or biofluids. The main pitfalls are the suppression of minor compounds, low metabolite coverage and the impossibility to detect certain families, combined with the requirement of non-selective approaches for untargeted analysis. Herein, we developed a new analytical extraction method for untargeted metabolomics using a non-selective procedure based on three phase hollow fiber liquid phase microextraction aided by ultrasound (three-phase-UA-HF-LPME) followed by gas chromatography-mass spectrometry. As a proof of concept, the method has been validated for human milk (HM). The analytical method allows extracting organic nitrogenous compounds from HM, which was not possible using the conventional liquid–liquid extraction (LLE) and provided cleaner chromatographic profiles and mass spectra with lower background noise. Moreover, three-phase-UA-HF-LPME enhanced the extraction of a high number of metabolites from 1.65 to 3.27-fold compared to LLE, namely: fatty acids and derivatives (decanoic acid, lauric acid, palmitic acid, tetradecanoic acid, palmitoleic acid, stearic acid, myristic acid, linoleic acid, azelaic acid), lipids and lipid-like molecules (oleamide, monopalmitin), organic acids and derivatives (lactic acid, citric acid), amino acids and peptides (glycine, proline, glutamine). Otherwise, the extraction of carbohydrates and derivatives (urea, phosphoric acid, galactose) decreased the fold changes from 0.15 to 0.25. Results show that our proposed method is attractive owing to its limits of detection from 0.08 to 0.16 mg L−1, recoveries of 99–86 %, enrichment factors up to 123 and fold changes very satisfactory when compared with LLE. The validation by targeted metabolomics as well as the untargeted procedure showed that three-phase-UA-HF-LPME presents better sensitivity, enrichment factors, sample throughput and metabolite coverage than the conventional LLE method considered the gold-standard for untargeted metabolomics. Our results show insights into the possible application of HF for untargeted metabolomics with important analytical advantages in comparison with the LLE.

Characterization of a hydrophilic-lipophilic balanced SPME material for enrichment of analytes with different polarities from aqueous samples

The choice of the extraction material is a critical step in solid-phase microextraction (SPME), especially the extraction of analytes which strongly differ in their polarity is challenging. This study is intended to give first insights into the headspace extraction of analytes with large differences in polarity by using a novel hydrophilic-lipophilic-balanced (HLB) SPME material with different particle sizes (5 µm, 5 + 30 µm, and 30 µm) in classical SPME, as well as SPME arrow format. The obtained results were compared to conventional and already established divinylbenzene carbon wide-range polydimethylsiloxane (DVB-CWR-PDMS) and PDMS SPME arrow fibers. The chosen model analytes toluene, indole, phenol, anisole, o-xylene, naphthalene, 2-heptanone, n-dodecane, and lindane are assigned to different substance classes with Kaw values ranging from -5.0–2.5 and Kow values from 1.5 to 7.5. The highest amount of the analytes was extracted by the HLB 5 + 30 µm arrow and the HLB 5 µm arrow, whereas the HLB SPME with a six times smaller phase volume compared to an SPME arrow, performed almost as well as the DVB-CWR-PDMS arrow. The 8-point calibration with the 5 + 30 µm HLB SPME arrow in the range of 5–70 µg L−1 of the analytes showed good linearity with R2 values ranging from 0.9765 to 0.9982, MDLs from 0.9 to 6.2 µg L−1 and RSDs from 2 to 31 %. For all of the observed analytes, the HLB material performed better than the conventional extraction materials and has great potential to replace the conventional extraction materials in many applications.

Modern Approaches to the Extraction and Preconcentration of Biologically Active Compounds from Plant Samples by Microextraction Methods for Their Determination by Chromatography–Mass Spectrometry

The review considers the main trends in actively developing methods of solid-phase and liquid–liquid microextraction for the extraction, purification, and preconcentration of analytes from medicinal plants and plant materials, the use of new extractants and approaches to the preparation of samples of plant origin, and their compatibility with mass-spectrometric detection. Particular attention is paid to the analytical capabilities, advantages, and limitations of each of the approaches to extracting analytes from plant materials for the subsequent analysis of the obtained extracts by chromatography–mass spectrometry.

Modern Approaches to the Extraction and Preconcentration of Biologically Active Compounds from Plant Samples by Microextraction Methods for Their Determination by Chromatography–Mass Spectrometry

The review considers the main trends in actively developing methods of solid-phase and liquid–liquid microextraction for the extraction, purification, and preconcentration of analytes from medicinal plants and plant materials, the use of new extractants and approaches to the preparation of samples of plant origin, and their compatibility with mass-spectrometric detection. Particular attention is paid to the analytical capabilities, advantages, and limitations of each of the approaches to extracting analytes from plant materials for the subsequent analysis of the obtained extracts by chromatography–mass spectrometry.

High throughput system for preparing samples for genomic, epigenetic, transcriptomic, proteomic and metabolomic analysis

Multi-omics considers the analysis of complex biological “omes” (genome, epigenome, transcriptome, proteome, metabolome, and others). This exponentially growing systems biology approach aims to better understand phenotypes in health and disease and as such identify biomarkers of disease and drug targets. The basic workflow is divided into an upstream sample preparation step, and corresponding downstream assays. To prepare samples for these assays biospecimen are treated to extract analytes such as chromatin, DNA, RNA, protein and metabolites. Often these sample preparation steps are done using cavitation. Current tools such as ultrasonic horns, and even many commercial sample preparation instruments, can be highly inconsistent, leading to unreliable assays. In order to overcome the problems of inconsistency, an instrument was designed and built with a transducer array (free field pressures P + = 30 MPa, P– = 12 MPa) capable of processing samples directly in standard 96-well microplates. An array of transducers is mounted below a microplate, coupled to a lens array that focuses acoustic energy into each well of a microplate. Intense cavitation is generated in each well. This process results in consistent analytes extraction that leads to consistently reproducible results. The authors have a financial conflict of interest. [Funded by NIH R33CA191135, R21GM111439, R01DK103849, R42HG010855, U01CA246503, and R44GM122097.]

TiO2@COF-based solid-phase microextraction combined with UHPLC-MS/MS for the rapid determination of potential biomarkers of phosphatidylcholines and lysophosphatidylcholines in head and neck cancers.

Phosphatidylcholine (PC) and lysophosphatidylcholine (LPC), two types of phospholipids (PLs), have been reported to be closely correlated with head and neck cancers of laryngeal cancer (LC) and thyroid cancer (TC), which make their analysis crucial. TiO2@COF-based solid-phase microextraction (SPME) coupled to UHPLC-MS/MS was developed for the rapid and accurate detection of seven potential PL biomarkers from small amounts of serum in this work. The combination of TiO2 and COF proves to be effective for the extraction of the target analytes. Under optimal conditions, the developed TiO2@COF-based SPME-UHPLC-MS/MS method revealed good linearity (R2 ≥ 0.997) with LODs ranging from 0.05 to 0.38ng/mL for PLs, the extraction recoveries and matrix effects ranging from 83.09-112.03% and 85.38-113.67%, respectively. As a high-throughput pretreatment method, satisfactory probe-to-probe reproducibility rates of 2.7-10.1% were obtained. Finally, the TiO2@COF-based SPME-UHPLC-MS/MS method was applied to analyze LPC 14:0, LPC 16:0, LPC 18:0, LPC 18:1, LPC 19:0, PC 16:0/18:1, and PC 18:0 in serum samples from early LC patients (n = 15), early TC patients (n = 15), and healthy volunteers (n = 15). The results indicated that cancer patients could be effectively differentiated from healthy controls using orthogonal partial least squares discriminant analysis (OPLS-DA). In conclusion, the established TiO2@COF-based SPME-UHPLC-MS/MS method is reliable for the rapid determination of the seven PLs in serum samples, which is promising for early diagnosis of head and neck cancers.

Solid-Phase Microextraction Techniques and Application in Food and Horticultural Crops.

Solid-phase microextraction (SPME) is a sample preparation technique which utilizes small amounts of an extraction phase for the extraction of target analytes from investigated sample matrices. Its simplicity of use, relatively short sample processing time, and fiber reusability have made SPME an attractive choice for many analytical applications. SPME has been widely applied to the sampling and analysis of environmental, food, aromatic, metallic, forensic, and pharmaceutical samples. Solid phase microextraction is used in horticultural crops, for example, to determine water and soil contaminants (pesticides, alcohols, phenols, amines, herbicides, etc.). SPME is also used in the food industry to separate biologically active substances in food products for various purposes, for example, disease prevention, determining the smell of food products, and analyzing tastes. SPME has been applied to forensic analysis to determine the alcohol concentration in blood and that of sugar in urine. This method has also been widely used in pharmaceutical analysis. It is a solvent-free sample preparation technique that integrates sampling, isolation, and concentration. This review focuses on recent work on the use of SPME techniques in the analysis of food and horticultural crops.

Lower endoscopy, early-onset, and average-onset colon cancer among Medicaid beneficiaries with and without HIV.

Studies suggest a lower colorectal cancer (CRC) risk and lower or similar CRC screening among people with HIV (PWH) compared with the general population. We evaluated the incidence of lower endoscopy and average-onset (diagnosed at ≥50) and early-onset (diagnosed at <50) colon cancer by HIV status among Medicaid beneficiares with comparable sociodemographic factors and access to care. We obtained Medicaid Analytic eXtract (MAX) data from 2001 to 2015 for 14 states. We included 41 727 243 and 42 062 552 unique individuals with at least 7 months of continuous eligibility for the endoscopy and colon cancer analysis, respectively. HIV and colon cancer diagnoses and endoscopy procedures were identified from inpatient and other nondrug claims. We used Cox proportional hazards regression models to assess endoscopy and colon cancer incidence, controlling for age, sex, race/ethnicity, calendar year and state of enrollment, and comorbidities conditions. Endoscopy and colon cancer incidence increased with age in both groups. Compared with beneficiaries without HIV, PWH had an increased hazard of endoscopy; this association was strongest among those 18-39 years [hazard ratio: 1.85, 95% confidence interval (95% CI) 1.77-1.92] and attenuated with age. PWH 18-39 years also had increased hazard of early-onset colon cancer (hazard ratio: 1.66, 95% CI:1.05-2.62); this association was attenuated after comorbidity adjustment. Hazard ratios were null among all beneficiaries less than 50 years of age. PWH had a lower hazard of average-onset colon cancer compared with those without HIV (hazard ratio: 0.79, 95% CI: 0.66-0.94). PWH had a higher hazard of endoscopy, particularly at younger ages. PWH had a lower hazard of average-onset colon cancer. Early-onset colon cancer was higher among the youngest PWH but not associated with HIV overall.

B-307 Direct Quantitation of 77 Therapeutic and Clinical Toxicology Drugs in Dried Blood Spots Using the Fully Automated Transcend DSX-1 System

Abstract Background The dried blood spot (DBS) sampling technique is advantageous over the traditional liquid blood collection due to its minimal invasiveness, smaller sample volume, improved analyte stability, and ease of storage and transportation, resulting in its increasing usage in therapeutic drug monitoring and clinical toxicology. Here, we describe a fully automated workflow to rapidly extract and quantify a wide range of therapeutic drugs and drugs of abuse in DBS using the Thermo Scientific™ Transcend™ DSX-1 system, fulfilling the routine drug monitoring needs in the clinical laboratories. Methods Calibrators in blood are spotted on the DBS cards, analytes are extracted with the innovative flow-through desorption technology, and their corresponding internal standards (IS) are introduced via an automated IS addition module in the dried spot autosampler. The 2-dimensional TurboFlow technology allows the removal of interferences from the extracted samples before analytical separation. An integrated software controls every step of the sample desorption and separation. Analyte quantitation is performed on the Thermo Scientific™ TSQ Altis™ Plus triple quadrupole mass spectrometer, and the data is analyzed in TraceFinder™ software. Results A total of 77 therapeutic and clinical toxicology drugs from eleven classes, including anticonvulsants, antidepressants, antihistamines, antipsychotics, benzodiazepines, cocaine, dissociatives, opioids, and stimulants, are quantified in a single injection from DBS cards using a rapid automated method on a Transcend DSX-1 system. DSX-1 combines a dried spot module for direct analyte extraction with Transcend™ UHPLC for online sample separation using the TurboFlow technology. The method only takes 4.3 min from analyte extraction to MS detection. Good calibration curves with R2 &amp;gt; 0.98 are achieved using a weighting factor of 1/x, and the limit of quantification (LOQ) values are established with % RSD and % CV &amp;lt; 15, │% Diff│ &amp;lt; 20, and relative ion ratio &amp;lt; %20. The LOQ values are all in the low ng/mL levels, which largely meet the screening and confirmation sensitivity needs of analytical methodologies in routine clinical laboratories. Conclusion A fully automated LC-MS-based workflow is developed to rapidly and reliably quantitate 77 compounds therapeutic and clinical toxicology drugs in dried blood spots.

B-162 Direct Quantitation of Five Immunosuppressant Drugs in Dried Whole Blood Spots by a Fully Automated DSM-LC-MS System

Abstract Background Liquid chromatography-mass spectrometry (LC-MS) is increasingly used in clinical research to quantify immunosuppressant drugs in whole blood as it can offer higher sensitivity and selectivity than other analytical techniques. LC-MS systems may be coupled with upstream dried matrix spot modules within one high-throughput, integrated and online workflow, allowing the extraction of matrices such as whole blood from pre-collected sample cards collected in a quick and minimally invasive manner. In this poster, such a workflow will be utilized to demonstrate the quantitation of five commonly monitored therapeutic immunosuppressants; cyclosporin A, everolimus, mycophenolic acid, sirolimus and tacrolimus. Methods Calibration and QC samples were prepared in whole blood. 10 μL of each calibrant was then spotted in triplicate on DBS cards. Immunosuppressants and standards were extracted using a Thermo Scientifc™ Transcend™ DSX-1 Systems via flow-through desorption with a heated clamp. TurboFlow allowed interference removal in the extracted samples prior to analytical separation. An integrated software, Aria MX, controlled each step of sample desorption and separation. Analyte quantitation was performed by a TSQ Altis™ mass spectrometer, and the data was analyzed using TraceFinder™ 5.1 General Quan software. Results Five commonly therapeutically monitored immunosuppressant drugs were quantified from blood spotted onto DBS cards using a fully automated workflow, resulting in a highly sensitive 5-minute method. Calibration curves were fitted using a weighting factor of 1/x with requirements of R2 &amp;gt; 0.98, RSD/CV &amp;lt; 15%. The calibrants were used to determine the limits of detection (LODs) and quantitation (LOQs) shown in the below table. Conclusion A complete, integrated and fully automated workflow has been developed to rapidly and robustly quantify immunosuppressant drugs from dried blood spots. Quick and reproducible extraction of each target analyte and efficient chromatographic separation facilitated a 5-minute method for the quantitation of five of the most commonly therapeutically monitored immunosuppressant drugs.

Direct determination of glyphosate and its metabolite in the plant raw material and environmental objects by chromatography-mass spectrometry

Glyphosate is a popular herbicide often used for desiccation of crops. The use of glyphosate-based chemicals leads to the contamination of agricultural products, soils, surface and groundwater. For safety control of raw materials of the plant origin and environmental objects, a technique based on the tandem chromato-mass-spectrometry was developed to provide for the quantitative determination of glyphosate and aminomethylphosphonic acid (AMPA) without prior derivatization. The technique is characterized by a relatively simple and cost-effective sample preparation procedure. The compounds are extracted from plant raw materials with an acetic acid solution of methanol in water, in the presence of 2-aqueous disodium salt of ethylenediamine-N,N,N’,N’-tetraacetic acid (EDTA-Na2) and dichloromethane. Extraction of analytes from water samples is carried out in the presence of EDTA-Na2 and acetic acid; whereas their extraction from soil samples is carried out with a weak solution of ammonia. The extracts are purified by solid phase extraction (SPE), and proteins are precipitated with acetonitrile. Linear-dynamic ranges of glyphosate and AMPA determination are characterized by calibration curves with correlation coefficients (R) ≥0.99. The working range of glyphosate and AMPA determination in raw materials of plant origin was from 0.1 to 5.0 mg/kg; in surface and ground water from 0.001 to 0.05 mg/liter (glyphosate) and from 0.002 to 0.05 mg/liter (AMPA); in soils from 0.02 to 0.8 mg/kg (glyphosate) and from 0.04 to 0.8 mg/kg (AMPA). The values of the relative standard deviation range from 1.8 to 19.5%, with recovery levels ranging from 80.5 to 108.1%. The achieved values of the determination limits are consistent with the maximum permissible levels indicated in TR CU 015/2011 and SanPiN 1.2.3685–21.

Evaluation of the Long-Term Stability of Select Phenylacetylindole, Cycloalkylindole, Quinolinyl, and Carboxamide Synthetic Cannabinoids using LC-MS/MS.

Forensic toxicology laboratories often encounter casework backlogs, which raise concerns for drug stability that can be affected by long storage times, temperature, and preservatives, or the lack thereof. The focus of this research was to evaluate the impact of these factors on the stability of 17 synthetic cannabinoids in human whole blood and 10 associated metabolites in human urine. The fortified biological specimens were stored under room temperature (20°C), refrigerator (4°C), and freezer (-20°C) conditions for a period of 52 weeks. Preservatives included potassium oxalate, sodium ethylenediaminetetraacetic acid, and sodium fluoride. Extraction of analytes was conducted using supported liquid extraction and analyzed using a liquid chromatograph-tandem mass spectrometer. Under all three storage conditions, the majority of urine metabolites were stable up to 9 weeks. All analytes in frozen sodium fluoride preserved blood were stable at 21 to 52 weeks with the exception of APP-PICA. Analytes in blood that were stable to 52 weeks in the freezer generally had a core structure of a carbonyl substituent on a pyrazole or pyrrole with surrounding nonpolar groups. In contrast, compounds with two adjacent polar carbonyl functional groups experienced degradation at 1 week or less under ambient temperature and refrigeration. 5-fluoropentyl analogs, XLR11 and 5-fluoro ADB-PINACA, in comparison to their counterpart analytes, UR144 and ADB-PINACA, were unstable at earlier time points under all temperatures. Based on these data, forensic blood evidence suggesting the presence of synthetic cannabinoid compounds are recommended to be frozen with sodium fluoride and potassium oxalate preservatives for optimal quantitative results.

Electrophoretically deposited sulfonated poly(styrene-co-divinylbenzene) on a screw for microextraction of cationic dyes from aqueous solutions.

In the present work, a novel solid-phase microextraction on a screw (MES) was employed to extract cationic dyes (malachite green, methylene blue, and rhodamine B) from food samples and fish breeding pool water. The sulfonated poly(styrene-co-divinylbenzene) was electrophoretically deposited on the surface of the grooves of a screw. Then the screw was placed inside a silicon tube as a holder to create a channel to run a test solution through it. The extracted dyes on the coated screw were eluted by a suitable eluent. High-performance liquid chromatography with an ultraviolet/visible detector was utilized for the separation and analysis of the analytes. The effective parameters of the analyte extraction efficiency were optimized. Under optimum conditions, the limits of detection were 0.15μg/L, and calibration curves were linear in the range of 0.50-250.00μg/L, with coefficients of determination>0.989 for all studied dyes. The relative standard deviations of intra and inter-day (n=3) were in the range of 2.8%-7.0% and 7.0%-9.5%, respectively. The MES was applied as a simple and repeatable method with acceptable relative recoveries (82.0%-103.0%) for the determination of cationic dyes in grape nectar, ice pop, jelly powder, and fish breeding pool water.

Advantage of 3D printed casting mold induced microstructure on the extraction and transport of Cd(II) through polymer inclusion membranes

Polymer inclusion membranes (PIMs) are considered a green alternative to solvent extraction. Although their ability to perform simultaneous extraction and back-extraction of analytes in a single step is a great advantage, the rate of separation needs to be enhanced significantly to replace solvent extraction in industrial applications. Various approaches, such as inclusion of graphene oxide, cross-linking agents, alteration in feed and receiving medium, are adopted in PIMs fabrication process to elevate its separation performances. In this work, we have assessed, for the first time, the advantage of using fused deposition modeling (FDM) 3D printing to fabricate polymer inclusion membranes (PIMs) testing modules and casting molds. PIMs cast over the 3D-printed molds were examined in terms of their Cd(II) extraction and transport capability and compared with the performance of PIMs cast on a glass plate to highlight the distinct superiority of the former originating from the microstructures present on the casting mold. Moreover, all Cd(II) extraction and transport experiment were conducted in 3D-printed cells having optimized geometry. PIMs prepared with Aliquat® 336 (Methyltrialkylammonium chloride, 30 wt%) and poly(vinylidene fluoride-hexafluoropropylene; 70 wt%) were effective in extraction and transport of Cd(II) from the feed solution containing 20 mg·L−1Cd(II) in 0.5 M NaCl to the stripping solution made of 0.1 M HNO3. Although both PIMs (cast on the glass plate and 3D-printed mold) perform in a similar Cd(II) extraction manner, the transport of Cd(II) was more efficient through the latter. PIMs cast on 3D-printed mold exhibited 20 % enhancement in Cd(II) transport compared to the PIMs cast on glass plate. Microstructures present at the surface of the PIM cast on 3D printed casting mold create arranged patterns leading to more effective transport of metal ions through it. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to analyze the membrane surface structure. SEM images show the presence of microstructures separated by micrometer distance which significantly improves the effective surface area of the PIMs and accessibility to the aqueous medium. Such structures are also expected to promote diffusion layer profiles enhancing the mass transfer of Cd(II) to the membrane surface. The presence of different elements in the PIMs and insertion and elimination of Cd(II) within the PIMs in extraction and back-extraction experiments respectively were evaluated by energy dispersive x-ray (EDX) spectroscopy. The concentration of Cd(II) in the feed and receiving phase was followed with the atomic absorption spectrometry. Overall, this work underlines the superiority of adopting 3D-printing technology for modifying PIMs’ surface morphology, PIM-related set-up fabrication and performing demanding PIM-based experiments at a very low cost with enhanced performance.

Ultra-trace determination of cadmium in water and food samples by a thin-film microextraction using a supported liquid membrane combined with smartphone-based colorimetric detection.

A mixture of n-octanol and dithizone was introduced as an effective and novel extraction agent in a thin-film microextraction technique for the pre-concentration of cadmium ions. The extraction agent was immobilized on small pieces of porous polypropylene flat membrane as a supported liquid membrane. The analyte extraction was performed by immersing the modified film in the sample solution, and via a complex formation between the immobilized dithizone on the film and cadmium ions. After the thin-film microextraction process, the colored cadmium-dithizone complex was directly measured by a smartphone colorimetric analysis. Under optimized conditions, the linear dynamic range, the limit of detection, and the limit of quantification were 0.5-300.0, 0.1, and 0.4μg L-1, respectively. The developed technique was successfully employed to quantify cadmium ions in water and food samples. The high relative recovery values (95.0-103.0%) along with relative standard deviations of less than 2.5% were obtained for the spiked samples.

QuEChERS Extraction of PAHs from Various Soils and Sediments Followed by Chromatographic Determination

We studied the features of PAHs extraction by QuEChERS in the sample preparation of soils and bottom sediments of various compositions followed their determination by gas chromatography–mass-spectrometry. The test samples were soils of sandy, loamy sand, loamy, and clayey types and bottom sediments of loamy sand type. The mineralogical composition and organic matter content of the samples were used to predict how PAHs were retained by the soils and sediments. The impact of ultrasonic treatment on analyte extraction with subsequent identification by chromatography was assessed. No ultrasonic treatment was required to extract and determine all PAHs (up to 100%) in sandy and loamy sand soils and low-molecular-weight PAHs in all test samples. The QuEChERS extraction and determination of high-molecular-weight PAHs in clay type soil samples and loamy sand bottom sediments required a 10-min ultrasonic treatment, while the recoveries of analytes were higher than 87 and 90%, respectively. The analysis of a loamy soil sample with a high organic matter content was the most challenging. To extract over 70% of high-molecular-weight PAHs from a sample of this type using the QuEChERS technique, the binary acetonitrile–acetone (1 : 1) extractant rather than conventional acetonitrile was used with the simultaneous 15-min ultrasonic treatment.

A Self-Powered Microfluidic-Based Flexible Triboelectric Sensor for Noninvasive Sweat Analysis

Sweat, an abundant biofluid containing rich source of physiological and metabolic information regarding the health of an individual, with the potential for noninvasive extraction. Health monitoring via quantitative sweat analysis could potentially preclude the need for periodic blood sample assessments. Continuous monitoring of key electrolytes such as sodium can provide a wide range of information from electrolyte imbalance to diagnosis of cystic fibrosis. This makes the quantification of sodium ions important since the loss of sodium could lead to hyponatremia. About 5% of the adults and about 35% of hospitalized patients suffer from hyponatremia which makes it one of the most common electrolyte disorder. Therefore, developing a robust sensing platform is indispensable. A flexible, thin class of microfluidic device has been introduced of late, that can be used for sweat extraction and quantifiable monitoring of the sweat analytes. However, these devices operate with high cost, complex design, and an active power source. Therefore, in our study, we address such challenges by developing a triboelectric nanogenerator (TENG) based self-powered microfluidic device that works on contact electrification. The wearable microfluidic device monitors the sodium levels in the sweat of the individual extracted in a non-invasive manner. The flexible microfluidic channel utilizes the capillary action generated with the periodic finger tapping to transport the sweat from skin to the sensing area. The transported sweat is used in the liquid - solid interaction between the sweat and microfluidic channels with electrode coated with ion selective membrane (ISM) to obtain triboelectric output. The ISM coating on the electrode is able to selectively detect the target analyte which results in a significant difference in output. This study demonstrates a flexible microfluidic based self-powered noninvasive sweat sensor which has potential applications in analysis of electrolyte loss through sweat.