Advanced Sample Preparation Techniques Research Articles

Extraction of synthetic cathinones from biological samples: A systematic review

Analysis of biological samples containing synthetic cathinones has become a significant area of interest for researchers in recent years, because synthetic cathinones can cause adverse reactions such as delusions and hallucinations. Generally, the intricate nature of the sample matrix and exceedingly low drug concentration in biological samples present significant challenges for the determination of target substances. Accordingly, scientists were dedicated to the advancement of effective sample preparation techniques to address these difficulties. However, the current reviews involved in synthetic cathinones all focused on detection methods. A systematic review focusing on sample preparation for the quantification of synthetic cathinones is still lacking. In light of that, this paper reviewed the most commonly used sample preparation techniques for synthetic cathinones. Recent advances in sample preparation techniques for synthetic cathinones in different biological samples such as blood, urine, oral fluid and hair samples were discussed. In addition, we prospected the challenges and the future perspectives of biological sample preparation techniques for synthetic cathinones determination.

Sensing volatile organic compounds in aquatic samples: a review

ABSTRACT Volatile organic compounds (VOCs) are toxic and harmful to human health; thus, their detection in water samples is critical for ensuring safe drinking water and protecting public health. The aim of this review was to explore the various techniques available in the literature for detecting VOCs in water samples and discuss their features, advantages, and limitations in facilitating fast and rapid VOC analysis. Established techniques such as gas chromatography and mass spectrometry offer high sensitivity and selectivity but are often hindered by complexity and cost. In contrast, emerging technologies like microfluidic gas sensors and cantilever-based sensors provide portable and real-time monitoring capabilities, although they may be susceptible to matrix effects. Overcoming these challenges requires advanced sample preparation techniques and method optimization. Additionally, the integration of machine learning algorithms and nanotechnology shows promise for enhancing sensitivity and precision in the detection of VOCs. By overcoming these limitations and leveraging technological advancements, researchers can improve water quality monitoring and help protect the environment.

Innovative Solid-Phase Extraction Strategies for Improving the Advanced Chromatographic Determination of Drugs in Challenging Biological Samples.

In the past few decades, considerable scientific strides have been made in the subject of drug analysis in human biological samples. However, the risk caused by incorrect drug plasma levels in patients still remains an important concern. This review paper attempts to investigate the advances made over the last ten years in common sample preparation techniques (SPT) for biological samples based on solid sorbents, including solid-phase extraction (SPE) and solid-phase micro-extraction (SPME), and in particular in the field of molecularly imprinted polymers (MIPs), including non-stimuli-responsive and stimuli-responsive adsorbents. This class of materials is known as 'smart adsorbents', exhibiting tailored responses to various stimuli such as magnetic fields, pH, temperature, and light. Details are provided on how these advanced SPT are changing the landscape of modern drug analysis in their coupling with liquid chromatography-mass spectrometry (LC-MS) analytical techniques, a general term that includes high-performance liquid chromatography (HPLC) and ultra-high performance liquid chromatography (UHPLC), as well as any variation of MS, such as tandem (MS/MS), multiple-stage (MSn), and high-resolution (HRMS) mass spectrometry. Some notes are also provided on coupling with less-performing techniques, such as high-performance liquid chromatography with ultraviolet (HPLC-UV) and diode array detection (HPLC-DAD) detection. Finally, we provide a general review of the difficulties and benefits of the proposed approaches and the future prospects of this research area.

Skin emitted volatiles analysis for noninvasive diagnosis: the current advances in sample preparation techniques for biomedical application.

Human skin emits a series of volatile compounds from the skin due to various metabolic processes, microbial activity, and several external factors. Changes in the concentration of skin volatile metabolites indicate many diseases, including diabetes, cancer, and infectious diseases. Researchers focused on skin-emitted compounds to gain insight into the pathophysiology of various diseases. In the case of skin volatolomics research, it is noteworthy that sample preparation, sampling protocol, analytical techniques, and comprehensive validation are important for the successful integration of skin metabolic profiles into regular clinical settings. Solid-phase microextraction techniques and polymer-based active sorbent traps were developed to capture the skin-emitted volatile compounds. The primary advantage of these sample preparation techniques is the ability to efficiently and targetedly capture skin metabolites, thus improving the detection of the biomarkers associated with various diseases. In further research, polydimethyl-based patches were utilized for skin research due to their biocompatibility and thermal stability properties. The microextraction sampling tools coupled with high sensitive Gas Chromatography-Mass Spectrometer provided a potential platform for skin volatolomes, thus emerging as a state-of-the-art analytical technique. Later, technological advancements, including the design of wearable sensors, have enriched skin-based research as it can integrate the information from skin-emitted volatile profiles into a portable platform. However, individual-specific hydration, temperature, and skin conditions can influence variations in skin volatile concentration. Considering the subject-specific skin depth, sampling time standardization, and suitable techniques may improve the skin sampling techniques for the potential discovery of various skin-based marker compounds associated with diseases. Here, we have summarised the current research progress, limitations, and technological advances in skin-based sample preparation techniques for disease diagnosis, monitoring, and personalized healthcare applications.

B-358 Application of Surface-Enhanced Raman Spectroscopy to Improve Sensitivity of Clinical Assays

Abstract Background Current efforts to expand the pool of available markers that can be analyzed in clinical settings is hampered by limited volumes of biomaterial-rich fluids and low concentrations of certain analytes, coupled with poor sensitivity of existing detection techniques. Although progress has been made using advanced sample preparation or assay techniques such as miRNeasy or ELISA for genomic and protein assays, respectively, little research has focused on adapting new optical methods as detection modes in the clinic. Amplified Sciences has developed an enzymatic activity assay platform using SERS detection to improve diagnostic sensitivities in multiple disease indications. Along with the experts at Wasatch Photonics, research focused on adaptation of this assay platform has enabled investigation of multiple markers of disease that had previously been undervalued or overlooked, as well as stacking of multiple markers in precious, low-volume samples. Methods Building upon previously published data using gastricsin as a marker to identify benign, non-mucinous pancreatic cysts, Amplified Sciences has added several SERS laser wavelengths, and different sample preparation methods to the existing platform. To examine the sensitivities of laser and dye combinations, solutions representative of assay samples containing rhodamine-dimer dye-labeled peptide were tested using Wasatch Photonics Raman spectrometers at 532, 638, 785, and 830 nm laser wavelengths. Samples at different pH were analyzed after addition of colloidal Au or Ag nanoparticles to determine the impacts of sample preparation on SERS spectral features. After drying in a desiccator overnight, the samples were reanalyzed to assess the stability of the SERS signals. As a pertinent application of this technology, an activity assay was developed for the known COVID protease 3ClPro. Release of rhodamine dimer dye as a result of 3ClPro cleavage of the substrate was quantified using SERS. The data were analyzed using Bruker OPUS Software package, and plotted using Graphpad Prism 9. Results Each laser, buffer, and metal used for SERS provided a unique spectral signature, suggesting that different transitions are available and potentially tunable depending on the application under investigation. Sensitivity was, as expected, best with the 532 nm SERS system purportedly due to enhancement factors, and the resonance impacts of rhodamine dyes at 532 nm. It was found that the Limit of Detection of Rhodamine-dimer dye was 100-fold lower with SERS compared to fluorescence, even after a 3-fold dilution with colloidal Ag. However, the remaining lasers could be more finely tuned, and, thus, provide alternate spectral properties, and different sensitivities which has implications when new dye classes are introduced into the platform. Furthermore, when SERS was applied to the 3ClPro assay, it was determined that activity could be detected below the dimerization concentration of 3ClPro, described in the literature as ∼25 nM. Also, a monomeric version of 3ClPro that is expected to have no reactivity with the substrate was found to display activity above background at concentrations as low as 1 µM. Conclusion SERS is an appropriate method for measuring activity in clinically relevant markers of disease, with tunable characteristics based upon the dye composition and the spectrometer in use.

Advances on Hormones in Cosmetics: Illegal Addition Status, Sample Preparation, and Detection Technology.

Owing to the rapid development of the cosmetic industry, cosmetic safety has become the focus of consumers' attention. However, in order to achieve the desired effects in the short term, the illegal addition of hormones in cosmetics has emerged frequently, which could induce skin problems and even skin cancer after long-term use. Therefore, it is of great significance to master the illegal addition in cosmetics and effectively detect the hormones that may exist in cosmetics. In this review, we analyze the illegally added hormone types, detection values, and cosmetic types, as well as discuss the hormone risks in cosmetics for human beings, according to the data in unqualified cosmetics in China from 2017 to 2022. Results showed that although the frequency of adding hormones in cosmetics has declined, hormones are still the main prohibited substances in illegal cosmetics, especially facial masks. Because of the complex composition and the low concentration of hormones in cosmetics, it is necessary to combine efficient sample preparation technology with instrumental analysis. In order to give the readers a comprehensive overview of hormone analytical technologies in cosmetics, we summarize the advanced sample preparation techniques and commonly used detection techniques of hormones in cosmetics in the last decade (2012-2022). We found that ultrasound-assisted extraction, solid phase extraction, and microextraction coupled with chromatographic analysis are still the most widely used analytical technologies for hormones in cosmetics. Through the investigation of market status, the summary of sample pretreatment and detection technologies, as well as the discussion of their development trends in the future, our purpose is to provide a reference for the supervision of illegal hormone residues in cosmetics.

Correlative Light and Electron Cryo-Microscopy Workflow Combining Micropatterning, Ice Shield, and an In-Chamber Fluorescence Light Microscope.

In situ cryo-electron tomography (cryo-ET) is the most current, state-of-the-art technique to study cell machinery in its hydrated near-native state. The method provides ultrastructural details at sub-nanometer resolution for many components within the cellular context. Making use of recent advances in sample preparation techniques and combining this method with correlative light and electron microscopy (CLEM) approaches have enabled targeted molecular visualization. Nevertheless, the implementation has also added to the complexity of the workflow and introduced new obstacles in the way of streamlining and achieving high throughput, sample yield, and sample quality. Here, we report a detailed protocol by combining multiple newly available technologies to establish an integrated, high-throughput, optimized, and streamlined cryo-CLEM workflow for improved sample yield. Key features • PRIMO micropatterning allows precise cell positioning and maximum number of cell targets amenable to thinning with cryo focused-ion-beam-scanning electron microscopy. • CERES ice shield ensures that the lamellae remain free of ice contamination during the batch milling process. • METEOR in-chamber fluorescence microscope facilitates the targeted cryo focused-ion-beam (cryo FIB) milling of these targets. • Combining the three technologies into one cryo-CLEM workflow maximizes sample yield, throughput, and efficiency. Graphical overview.

Enhanced Spatial Mapping of Histone Proteoforms in Human Kidney Through MALDI-MSI by High-Field UHMR-Orbitrap Detection.

Core histones including H2A, H2B, H3, and H4 are key modulators of cellular repair, transcription, and replication within eukaryotic cells, playing vital roles in the pathogenesis of disease and cellular responses to environmental stimuli. Traditional mass spectrometry (MS)-based bottom-up and top-down proteomics allows for the comprehensive identification of proteins and of post-translational modification (PTM) harboring proteoforms. However, these methodologies have difficulties preserving near-cellular spatial distributions because they typically require laser capture microdissection (LCM) and advanced sample preparation techniques. Herein, we coupled a matrix-assisted laser desorption/ionization (MALDI) source with a Thermo Scientific Q Exactive HF Orbitrap MS upgraded with ultrahigh mass range (UHMR) boards for the first demonstration of complementary high-resolution accurate mass (HR/AM) measurements of proteoforms up to 16.5 kDa directly from tissues using this benchtop mass spectrometer. The platform achieved isotopic resolution throughout the detected mass range, providing confident assignments of proteoforms with low ppm mass error and a considerable increase in duty cycle over other Fourier transform mass analyzers. Proteoform mapping of core histones was demonstrated on sections of human kidney at near-cellular spatial resolution, with several key distributions of histone and other proteoforms noted within both healthy biopsy and a section from a renal cell carcinoma (RCC) containing nephrectomy. The use of MALDI-MS imaging (MSI) for proteoform mapping demonstrates several steps toward high-throughput accurate identification of proteoforms and provides a new tool for mapping biomolecule distributions throughout tissue sections in extended mass ranges.

Advanced sample preparation techniques for rapid surface-enhanced Raman spectroscopy analysis of complex samples

Surface-enhanced Raman spectroscopy (SERS) is a powerful and promising analytical technique for fast, non-destructive, and sensitive analysis of trace analytes. However, the serious matrix interference effect of complex sample is a bottleneck that limited rapid SERS analysis. Therefore, it is essential to introduce proper sample preparation techniques to address the limitation for advancing SERS analysis. With adaptable sample preparation techniques, target substances could be separated and purified from complex matrices, matrix interference effect could be eliminated/reduced, and finally pure SERS spectra could be obtained. However, the process of traditional sample preparation usually requires the tedious and time-consuming operation, large solvent consumption, high labor intensity, as well as low efficiency. Given that SERS is an ultrafast analytical technique, there is a great desire to develop advanced/modern sample preparation techniques for fast and efficient analysis of complex samples. To attract much attention and raise research enthusiasm on the beginning, recent development on advanced sample preparation techniques for rapid SERS analysis of complex sample was reviewed. (1) ‘All-in-one’ strategy for simultaneous separation, enrichment, and in-situ SERS detection. (2) Integrated strategy for high-speed pretreatment and high throughput analysis. (3) Derivatization strategy switches on the SERS activity of molecules with weak responses. (4) Field-assisted strategy for preconcentration acceleration. (5) Instrument combination strategy for online processing and real-time SERS analysis. Finally, conclusions and perspectives on future development were briefly discussed.

From Microscopy to Nanoscopy: Defining an Arabidopsis thaliana Meiotic Atlas at the Nanometer Scale.

Visualization of meiotic chromosomes and the proteins involved in meiotic recombination have become essential to study meiosis in many systems including the model plant Arabidopsis thaliana. Recent advances in super-resolution technologies changed how microscopic images are acquired and analyzed. New technologies enable observation of cells and nuclei at a nanometer scale and hold great promise to the field since they allow observing complex meiotic molecular processes with unprecedented detail. Here, we provide an overview of classical and advanced sample preparation and microscopy techniques with an updated Arabidopsis meiotic atlas based on super-resolution microscopy. We review different techniques, focusing on stimulated emission depletion (STED) nanoscopy, to offer researchers guidance for selecting the optimal protocol and equipment to address their scientific question.

Recent advances in sample preparation techniques for the lipid profiling based on chromatography-mass spectrometry

As the main structural components of cellular and sub-cellular membranes, lipids are a major source of energy and play an important role in various biological processes such as cellular signaling. Lipid profiling has attracted increasing attention in recent years, and chromatography-mass spectrometry techniques for lipid profiling occupy a dominant position in this regard. Sample preparation, which aims at enriching trace substances and reducing matrix interferences, is a crucial step in the analysis of lipids for the intricacy of sample matrices. Here, we review recent developments in sample preparation techniques based on chromatography-mass spectrometry and their application to lipid profiling. Various sample preparation techniques are described and summarized. The extraction methods based on liquid phase included liquid-liquid extraction and single organic solvent extraction. The extraction methods based on solid phase involved solid-phase extraction and solid-phase microextraction. The field-assisted extraction methods cover supercritical fluid extraction, pressurized liquid extraction, microwave-assisted extraction, and ultrasound-assisted extraction. Moreover, online coupling sample preparation methods and sample preparation methods for in vivo lipid analysis are presented. Finally, the problems and trends in sample preparation techniques for lipid profiling based on chromatography-mass spectrometry are discussed. It is believed that efficient development of sample preparation techniques would help improve the sensitivity and selectivity of lipid profiling as well as the analysis speed.

Front Cover: Recent advances in sample preparation techniques in China

Front Cover: Recent advances in sample preparation techniques in China

Recent advances in sample preparation techniques in China.

Sample preparation is the procedure before instrumental analysis and significant to its effectiveness and efficiency. However, this procedure is usually time-consuming, labor intensive, and prone to error. In the last decade, the development of sample preparation techniques has received increasing attention, especially in complex sample application. To pretreat samples faster and more effectively, advanced materials, instrumentation, and methods have been combined with typical techniques, including extraction, membrane separation, and chemical conversion techniques. Researchers in China focused on the development of simple, efficient sample preparation methods with selective enrichment and rapid separation capabilities for target analysis in complicated sample matrix and contribute almost a half of the publications in this specific field. In this review, a panorama of sample preparation techniques in China has been composed from more than 140 references, and we highlight some promising methods developed during recent years and introduce different separation materials with respect to these methods.

Current direction and advances in analytical sample extraction techniques for drugs with special emphasis on bioanalysis.

Analytical techniques may not be compatible or sufficiently sensitive to the analytes, unless it undergoes a specific sample extraction procedure. Sample extraction can be considered as one of the key steps in analysis. Analysis of a poorly treated sample may produce inferior quality of analytical data. Continuous advancement and development of newer sample extraction techniques such as solid phase microextraction, ultrasound, magnetically and microwave assisted magnetic extraction; electro-membrane extraction and dried blood spotting are to address the shortcomings of the existing techniques and to provide more automation, minimizing preparation time and make them high throughput. This review summarizes the suitability of application of the advanced sample preparation techniques available for chemical and bioanalysis in a comprehensive manner. This review also provides a scientific guidance for selecting the appropriate sample extraction technique based on sample type.

Proteomics Method to Identification of Protein Profiles in Exosomes.

Exosomes are membrane-bound nanovesicles that transport molecular signals (e.g., proteins) between cells and are released from a wide range of cells, including the human placenta. Interestingly, the levels of exosomes present in maternal circulation are higher in preeclamptic pregnancies and their protein content profile change in response to the microenvironment milieu. Through the discovery of candidate biomarkers, mass spectrometry (MS)-based proteomics may provide a better understanding of the pathophysiology underlying pregnancy-associated disorders. With advances in sample preparation techniques, computational methodologies, and bioinformatics, MS-based proteomics have addressed the challenge of identifying and quantifying thousands of proteins and peptides from a variety of complex biological samples. Despite increasing interest in biomarker diagnostics, the complex nature of biological matrices (e.g., plasma) poses a challenge for candidate biomarker discovery. Here we describe a workflow to prepare exosomes for proteomic analysis.

Matrix using SPE and LC-MS/MS

Drug analysis from whole blood is gaining popularity due to a more complete measurement of analytes in the biological system. Historically, most drug screens have been performed using immunoassay and similar technologies. These techniques often lack specificity and sensitivity necessary for today's complex legal requirements. In this poster, we demonstrate a fast, robust technique for the screening of a broad range of drugs from whole blood utilizing SPE and tandem mass spectrometry. Forty-one compounds, which include opiates (both natural and synthetic), amphetamines, benzodiazepines, phenylpiperidines, a muscle relaxant, and some illicit drugs (PCP and cocaine metabolite) were tested. Utilizing advanced sample preparation techniques we simplify a complicated matrix to allow for a fast and successful multi-component analysis by LC-MS/MS. Six pretreatment options for whole blood were investigated. The volume of whole blood used was 0.25 mL. A 5% zinc sulfate and acetonitrile combination worked for most classes. Benzodiazepines had a better overall response with 10% MeOH in ACN. However, there was not a single pretreatment procedure that worked well for all classes of compounds. The supernatant was loaded onto the Strata-XC 30 mg/3 mL cartridges. Salts and most endogenous components were removed using a two-step, 0.1% formic acid and 30% methanol, wash. Analytes were eluted using 2 × 500 uL of ammoniated IPA/ethyl acetate solution. Samples were then acidified and evaporated to dryness at 40–45 °C under a gentle nitrogen stream. The dry residue was re-suspended in mobile phase and injected onto the column. The chromatographic separation was performed on a Kinetex 2.6 um Biphenyl 50 × 3.0 mm column. The best choice of mobile phase was 0.1% formic acid in water and 0.1% formic acid in methanol. The detection was achieved on an AB Sciex Triple Quad 4500 and/or a 4000 QTrap LC-MS/MS system. All analytes were detected under positive polarity and MRM scan function using two mass transitions. A MRM-IDA-EPI combination scan was used on a small sample set to verify the analyte purity. A detection limit of 10 ng/mL was achieved for all tested analytes using this method. Tramadol, propoxyphene, fentanyl, carisoprodol and meprobamate produced strong signals. The absolute lowest detection levels for these analytes have not yet been determined. Although a full calibration method was not vigorously tested, the upper end of the calibration range was deemed to be 1000 ng/mL. A quadratic fit with 1/× weighting factor was employed for calibration purposes. Early eluting analytes were well separated from the ion suppression zone by a retention factor of two, or by three times the dead volume. Isomeric/isobaric compounds were completely resolved by the biphenyl LC column by at least a factor of 2. A resolution value of 3.2 was obtained for morphine and hydromorphone. The described procedure provides a simple and reliable solution to screen a wide range of illicit and pain control compounds from a complicated matrix.

Advanced FIB sample preparation techniques for high resolution TEM investigations of HEMT structures

In this paper advanced sample preparation techniques based on focused ion beam (FIB) optimized for TEM investigation of high electron mobility transistor (HEMT) structures are presented. It is shown that the usage of an innovative in-situ lift-out method combined with X2 window and backside milling techniques as well as live thickness control and end point detection can significantly improve the quality of electron transparent samples required for high resolution TEM investigations. This advanced preparation flow is evaluated and demonstrated at GaN HEMT structures for atomic resolution TEM investigation.

Special focus issue: Bioanalysis of large molecules by LC-MS.

Special focus issue: Bioanalysis of large molecules by LC-MS.

Recent advances in sample preparation techniques to overcome difficulties encountered during quantitative analysis of small molecules from biofluids using LC-MS/MS

Liquid chromatography-mass spectrometry analysis of small molecules from biofluids requires sensitive and robust assays. Because of the very complex nature of many biological samples, efficient sample preparation protocols to remove unwanted components and to selectively extract the compounds of interest are an essential part of almost every bioanalytical workflow. This review describes the most common problems encountered during sample preparation, ways to optimize established sample preparation techniques and important recent developments to reduce or eliminate major interferents from biofluids.

Critical importance of the correction of contrast transfer function for transmission electron microscopy-mediated structural biology

Abstracts Background Transmission electron microscopy (TEM) is an excellent tool for studying detailed biological structures. High-resolution structure determination is now routinely performed using advanced sample preparation techniques and image processing software. In particular, correction for contrast transfer function (CTF) is crucial for extracting high-resolution information from TEM image that is convoluted by imperfect imaging condition. Accurate determination of defocus, one of the major elements constituting the CTF, is mandatory for CTF correction. Findings To investigate the effect of correct estimation of image defocus and subsequent CTF correction, we tested arbitrary CTF imposition onto the images of two-dimensional crystals of Rous sarcoma virus capsid protein. The morphology of the crystal in calculated projection maps from incorrect CTF imposition was utterly distorted in comparison to an appropriately CTF-corrected image. Conclusion This result demonstrates critical importance of CTF correction for producing true representation of the specimen at high resolution.