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The virtual special issues on Sample Preparation in Mass Spectrometry deals with methods and applications of sample preparation concepts that facilitate and ensure accurate analysis by mass spectrometry (MS), be it in direct (infusion) MS analysis or in hyphenated techniques. It contains articles on new sample preparation concepts, selective enrichment and derichment methods and materials, nanomaterial-based and microscale sample preparation, online-sample preparation strategies, derivatization/labelling, and their application to food, clinical, environmental analysis, metabolomics, proteomics, lipidomics, and glycomics.
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Solid-phase extraction with metal-organic frameworks MIL-101(Cr) combined with direct analysis in real time mass spectrometry for fast analysis of triazine herbicides
Xianjiang Li, Jiawei Xing, Cuilan Chang, Xin Wang, Yu Bai, Xiuping Yan and Huwei Liu
A method combining MIL-101(Cr) for SPE with DART-MS for the fast analysis of triazine herbicides in real water samples was developed. This approach combined the high enrichment of analytes by MIL-101(Cr) SPE and high throughput detection by DART-MS, offering a large enrichment factor, acceptable linear range, and high detection efficiency (only about 2 s for every dip-it). The whole analytical process is done within 30 min. Using the proposed method, satisfactory recoveries could be achieved for all analyzed triazine herbicides which demonstrates the reliability and practicability. These results showed that SPE with MOFs is an efficient sample preparation approach for DART-MS analysis and this method could find more applications in environmental analysis.
Keywords: DART-MS, Environment, MOFs, Nitrogen-containing heterocycles
Synthesis and surface engineering of magnetic nanoparticles for environmental cleanup and pesticide residue analysis – a review
Ranjeet Kaur, Abshar Hasan, Nusrat Iqbal, Samsul Alam, Mahesh Kr Saini and Syed Kalbe Raza
Magnetic nanoparticles are emerging materials that have attracted considerable attention from academics and researchers in multiple industries. The use of magnetite nanoparticles as adsorbents in water decontamination and pesticide residue analysis provides a convenient approach for separating and removing the target analytes by applying external magnetic fields. Technologies based on the utilization of magnetite nanoparticles are under active development as highly effective, efficient and economically viable nanoadsorbents. Among the main advantages of these nanomaterials is the possibility of surface modifications with different organic or inorganic coating agents to allow the removal of a wide range of target analytes with higher specificity. This review summarizes the use of MNPs for wastewater treatment and residue analysis in the past decade. The application of these methods is still limited in the early stage and more research in the field is certainly necessary. In conclusion, there is much recent interest in the use of engineered magnetite nanoparticles in wastewater treatment. However, uncertainties over the health impacts and environmental fate of these nanomaterials need to be addressed before their widespread application.
Keywords: Magnetic solid-phase extraction, Mass spectrometry, Metal detoxification, Nanomaterials, Pesticides, Preconcentration
Bulk derivatization and direct injection of human cerebrospinal fluid for trace level quantification of endogenous estrogens using trap-and-elute LC-MS/MS
Hui Fan, Barbora Papouskova, Karel Lemr, Jane G. Wigginton and Kevin A. Schug
An analytical method for parts-per-trillion level quantitative analysis of endogenous estrogen in human CSF has been developed and validated. To our knowledge, this is one of two existing methods for determining endogenous estrogen in human CSF, and is the only one that incorporates RAM technology. The key features of this method are bulk derivatization, direct injection, on-line sample preparation, and analysis of raw CSF sample. While reached LODs may be insufficient for some research and clinical studies, a potential strategy towards their decrease has been suggested and will be implemented in future studies.
Keywords: CSF, Estrogenic neuroprotection, Hormones, Mass spectrometry, Restricted-access media, Streamlined sample preparation
Sample preparation workflow for LC-MS/MS based analysis of nicotinamide adenine dinucleotide phosphate cofactors in yeast
Karin Ortmayr, Justyna Nocon, Brigitte Gasser, Diethard Mattanovich, Stephan Hann and Gunda Koellensperger
Typical LC-MS methods in metabolomics target not only one metabolite but at least several intermediates of certain metabolic pathways simultaneously. Although it would be desirable to include NADP+ and NADPH into such methods, to our experience this is hardly possible because these two analytes require special attention in all steps of the sample preparation and analysis workflow. The specific solution chemistry of NADP+ and NADPH and the biological importance of their ratio must be considered in the development of a dedicated method since small artefactual shifts in the intracellular levels lead to a very different biological interpretation. While this workflow has been evaluated here thoroughly and was shown to be appropriate for relative quantification of intracellular NADP+ and NADPH, future work will have to focus on the implementation of an isotope dilution strategy before absolute quantification of these important intracellular metabolites can be attempted.
Keywords: Mass spectrometry, Metabolite extraction, NADPH, Reduction charge, Reversed phase chromatography
Aspects of Trapping Efficiency And Matrix Effects in Development of a Restricted Access Media-Based Trap-and-Elute Liquid Chromatography-Mass Spectrometry Method
Barbora Papouskova, Hui Fan, Karel Lemr and Kevin A. Schug
A trap-and-elute LC–MS method was developed in order to reduce the time-consuming sample preparation for determination of estrogens in biological matrix. A careful optimization proved the necessity of selection of proper sample loading flow rates, as well as selection of the optimal stationary phase of the trap column. The best results were obtained when using C4 RAM column and a gradient of a flow rate for a sample injection. Furthermore, the matrix effects were evaluated in detail. It was discovered that proteins in plasma and serum significantly hinder the bulk derivatization of estrogens and that further research is needed to evaluate bulk derivatization efficiencies. While derivatization efficiencies may be enhanced through addition of more derivatization reagent, the gain in such a strategy should be ensured to overcome the loss from further dilution of the original sample during processing.
Keywords: Biological fluid, Bulk derivatization, Estradiol quantification, Estrogens, On-line sample preparation
Continuous-Flow Extractive Desorption Electrospray Ionization – Mass Spectrometry Coupled to Normal Phase Separations and for Direct Phospholipid Analysis from Cell Extracts
Li Li and Kevin A Schug
The presented CF-EDESI method provided a good example for bridging normal phase separation and MS. CF-EDESI also poses the characteristic as one of the ambient ionization method in direct analysis with minimum sample preparation. The feature of CF-EDESI makes it attractive to general analytical community due to its apparent potential in lipidomics, chiral, and even possibly LC–NMR/MS analyses. Given that prior work has also demonstrated its use for protein analysis, CF-EDESI appears to be a versatile, simple, and economical AI technique with a wide application for flow-through sample analysis.
Keywords: Ambient ionization, Chiral separation,Direct analysis, Phospholipids
Quantification of physiological levels of vitamin D3 and 25-hydroxyvitamin D3 in porcine fat and liver in subgram sample sizes
Anders Burild, Henrik L. Frandsen, Morten Poulsen and Jette Jakobsen
Most methods for the quantification of physiological levels of vitamin D3 and 25-hydroxyvitamin D3 are developed for food analysis where the sample size is not usually a critical parameter. In contrast, in life science studies sample sizes are often limited. The aim of this method was to quantify physiological levels of vitamin D3 and 25(OH)D3 by using LC–MS/MS in small tissue samples after alkaline saponification. Adipose tissue was chosen because it in itself is the tissue matrix with the highest content of fat and therefore, the matrix most critical for the alkaline hydrolysis. Only 0.2–1 g of porcine tissues were used with a LOQ <0.1 ng/g. The amount of organic solvent required is reduced nearly tenfold compared to conventional LC–UV methods. The sensitivity and the small sample size needed enables the study of vitamin D3 and 25(OH)D3 in samples obtained from living animals.
Keywords: Derivatization, Fat-soluble vitamins, Method validation, Metabolites, Tissues,
Urine Sample Preparation for Proteomic Analysis
Pawel Olszowy and Boguslaw Buszewski
Sample preparation for both environmental and more importantly biological matrices is a bottleneck of all kinds of analytical processes. This review summarizes obstacles and achievements in protein sample preparation of urine for proteome analysis using different tools for mass spectrometry analysis. The main aim is to present comprehensively the idea of urine application as a valuable matrix. Urinary proteomics has become a valuable method for biomarker discovery. However, in every case, investigators should have in mind problems as well as limitations that could rise during experiments and that could have background in appropriate sample collection, storage, and treatment.
Keywords: Bioanalysis, Biological matrices, Biomarkers, Mass spectrometry, Sample preparation
Multiresidue method for the determination of 227 pesticides in hot pepper (Capsicum annuum L.) by liquid chromatography with tandem mass spectrometry
Yong-Zhe Zhu, Mei-Ai Zhao, Ya Nan Feng and Jeong Han Kim
The aim of this work was to develop a low-cost, rapid, and simple extraction, and analysis procedure for multiclass pesticide residues in pepper samples. Different cleanup procedures based on the QuEChERS preparation method were evaluated based on their recoveries and RSD values. The performances of the proposed methods were evaluated for the simultaneous analysis of 227 pesticides in pepper samples and analyzed with a triple quadrupole LC−MS/ MS.
Keywords: Cleanup, Mass spectrometry, Multiresidue analysis, QuEChERS, Vegetables
Microextraction sample preparation techniques in biomedical analysis
Malgorzata Szultka, Pawel Pomastowski, Viorica Railean-Plugaru and Boguslaw Buszewski
Biologically active compounds in biological samples are found at relatively low concentration levels. Sample preparation of target compounds from biological, pharmaceutical, environmental, and food matrices is one of the most time-consuming steps. In addition, sample pretreatment procedures have to be more selective, cheap, quick, and environmentally friendly. Due to the time-consuming character, the observed trend of simplification, miniaturization, and minimization of the use of solvents led to other techniques, such as SPME or microextraction in packed syringe (MEPS) are observed. This review is dedicated to the description of microextraction techniques and their application in biomedical analysis.
Keywords: Biomedicine, Liquid-phase microextraction, Sample preparation, Solid-phase microextraction, Sorbents
Microextraction by packed sorbent liquid chromatography with time-of-flight mass spectrometry of triazines employing a molecularly imprinted polymer
Felipe Nascimento Andrade, Álvaro José Santos-Neto and Fernando Mauro Lanças
Synthesis of MIPs and their further employment in the simultaneous determination of atrazine, ametryn, simazine, simetryn, and terbutryn in corn samples using MEPS and LC–ESI-TOF for a combination of simplicity and effective separation and quantification of the analytes is reported here. The MEPS method was optimized using an experimental design applied to the selection of optimal experimental conditions, reducing the number of optimization experiments. The study of the selectivity coefficient showed that MIP received an effective imprinting effect regarding triazines in corn samples with 91.1–109.1% recoveries with good precision and accuracy.
Keywords: Corn, Herbicides, Microextraction, MIPs, Packed sorbents
Antioxidant activity guided separation of major polyphenols of marjoram (Origanum majorana L.) using flash chromatography and their identification by liquid chromatography coupled with electrospray ionization tandem mass spectrometry
Mohammad B. Hossain, Gabriel Camphuis, Ingrid Aguiló-Aguayo, Nirupama Gangopadhyay and Dilip K. Rai
Antioxidant activity guided fractionation was a useful tool in identifying the key polyphenols of marjoram. A rapid and easy-to-use solvent-based partitioning in combination with automated flash chromatographic fractionation has been used to separate the most antioxidant fractions. Flavonoids are the predominant class of polyphenols except rosmarinic acid, which is a hydroxycinnamic acid derivative. It could be shown that rosmarinic acid is the strongest antioxidant polyphenol in marjoram.
Keywords: Bioactive polyphenols, Liquid–liquid partitioning, Flavonoids, Food
Determination of fatty acids in soil samples by gas chromatography with mass spectrometry coupled with headspace solid-phase microextraction using a homemade sol–gel fiber
Qin Shuai, Xiaoxiao Ding, Yunjie Huang, Shuangshuang Xu, Shengrui Xu, Qiang Gao and Haidong Deng
A PEG/OH-TSO sol–gel SPME fiber was developed and applied for the analysis of fatty acids (Fas) in soil samples by GC–MS. Under the optimized conditions, the proposed analysis method showed good linearity, detection limits, precision, and recovery. The new approach may serve as an alternative detection of FAs in relatively complex matrices such as soil, peat, and sediments.
Keywords: Biomarkers, Environment, Sol–gel SPME fiber, Weak polar substances