Common Sample Preparation Techniques Research Articles

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.

Ultrafiltration-based Sample Preparation for Pharmaceutical Analysis

Pharmaceutical analysis plays an important role in all steps of drug development processes. Analysis of active pharmaceutical ingredients in biological samples needs sample preparation techniques to prevent the signal of the analyte from interferences coming from matrix components. Ultrafiltration is a well-known technique used in the food and pharmaceutical industry. Commercial ultrafiltration devices have been frequently used on proteomics and metabolomics studies for sample preparation. In pharmaceutical analysis, these devices have been employed to analyze the free concentration of drugs in biological fluids after filtration. However, they have been rarely used to determine the total concentration of targeted compounds when it is compared with some other common sample preparation techniques. Ultrafiltration-based sample preparation might be used to clean-up the sample easily from matrix components especially on bioanalysis performed with high-performance liquid chromatography (HPLC). In the case of using protein precipitation agents on filtration procedure, the quantitative recovery of this non-selective unique technique is competitive with solid-phase extraction.

Application of Hollow Fibre-Liquid Phase Microextraction Technique for Isolation and Pre-Concentration of Pharmaceuticals in Water.

In this article, a comprehensive review of applications of the hollow fibre-liquid phase microextraction (HF-LPME) for the isolation and pre-concentration of pharmaceuticals in water samples is presented. HF-LPME is simple, affordable, selective, and sensitive with high enrichment factors of up to 27,000-fold reported for pharmaceutical analysis. Both configurations (two- and three-phase extraction systems) of HF-LPME have been applied in the extraction of pharmaceuticals from water, with the three-phase system being more prominent. When compared to most common sample preparation techniques such as solid phase extraction, HF-LPME is a greener analytical chemistry process due to reduced solvent consumption, miniaturization, and the ability to automate. However, the automation comes at an added cost related to instrumental set-up, but a reduced cost is associated with lower reagent consumption as well as shortened overall workload and time. Currently, many researchers are investigating ionic liquids and deep eutectic solvents as environmentally friendly chemicals that could lead to full classification of HF-LPME as a green analytical procedure.

Comparison of sample preparation techniques and matrix effects correction methods for X-ray fluorescence determination of total iron and rock-forming elements in iron ores

The genesis of deposits determines wide variations in the mineral and chemical composition of iron ores. It is necessary to determine the content of not only the main ore element (Fe), but also the main rock-forming elements, especially those that affect the quality of the product obtained from the ore (for example, P and Mn). When determining Fe, Mg, Al, Si, P, Ca, Ti, and Mn in iron ores by wavelength-dispersive X-ray fluorescence analysis, two common sample preparation techniques were compared: pressing powder samples on a boric acid substrate and homogenization of calcined sample by fusion with lithium tetraborate. For each method, the repeatability of the measurement of analytical lines was evaluated, calibration equations were constructed using certified reference materials of iron ores of various types and two methods for matrix effects correction (fundamental parameters and empirical intensities) were compared. Iron ores samples from the Korshunovskoye, Rudnogorskoye and Tatyaninskoye deposits of the Angarsk ore province (north of the Irkutsk region and southeast of the Krasnoyarsk Krai) were analyzed by the certified atomic absorption and spectrophotometric techniques, and the results were compared with those obtained by X-ray fluorescence analysis. For the main ore element (Fe) and some rock-forming elements (Mg, Al, Si, P) determination, the fusion technique provided a smaller error, however, both techniques could be used to determine Ca, Ti, and Mn. The choice of the sample preparation technique for wavelength-dispersive X-ray fluorescence analysis of iron ores should be based on the appropriateness of the financial and labor costs and the necessary accuracy of the analysis. Keywords : wavelength-dispersive X-ray fluorescence analysis, iron ores, rock-forming elements, borate glasses, matrix effects correction DOI: http://dx.doi.org/10.15826/analitika.2020.24.2.005 Victor M. Chubarov 1 , Elena I. Borkhonova 2 , Alena A. Amosova 1 1 Vinogradov Institute of Geochemistry, SB RAS, 1 А Favorsky st., Irkutsk 664033, Russian Federation 2 Irkutsk State University, 1 Karl Marx st., Irkutsk 664003, Russian Federation

What you extract is what you see: Optimising the preparation of water and wastewater samples for in vitro bioassays

The assessment of water quality is crucial for safeguarding drinking water resources and ecosystem integrity. To this end, sample preparation and extraction is critically important, especially when investigating emerging contaminants and the toxicity of water samples. As extraction methods are rarely optimised for bioassays but rather adopted from chemical analysis, this may result in a misrepresentation of the actual toxicity.In this study, surface water, groundwater, hospital and municipal wastewater were used to characterise the impacts of common sample preparation techniques (acidification, filtration and solid phase extraction (SPE)) on the outcomes of eleven in vitro bioassays. The latter covered endocrine activity (reporter gene assays for estrogen, androgen, aryl-hydrocarbon, retinoic acid, retinoid X, vitamin D, thyroid receptor), mutagenicity (Ames fluctuation test), genotoxicity (umu test) and cytotoxicity. Water samples extracted using different SPE sorbents (Oasis HLB, Supelco ENVI-Carb+, Telos C18/ENV) at acidic and neutral pH were compared for their performance in recovering biological effects.Acidification, commonly used for stabilisation, significantly altered the endocrine activity and toxicity of most (waste)water samples. Sample filtration did not affect the majority of endpoints but in certain cases affected the (anti-)estrogenic and dioxin-like activities. SPE extracts (10.4 × final concentration), including WWTP effluents, induced significant endocrine effects that were not detected in aqueous samples (0.63 × final concentration), such as estrogenic, (anti-)androgenic and dioxin-like activities. When ranking the SPE methods using multivariate Pareto optimisation an extraction with Telos C18/ENV at pH 7 was most effective in recovering toxicity. At the same time, these extracts were highly cytotoxic masking the endpoint under investigation. Compared to that, extraction at pH 2.5 enriched less cytotoxicity.In summary, our study demonstrates that sample preparation and extraction critically affect the outcome of bioassays when assessing the toxicity of water samples. Depending on the water matrix and the bioassay, these methods need to be optimised to accurately assess water quality.

Analysis of Isoflavones in Foods.

In recent years the nutritional and bioactive properties of foods are being intensively investigated with a view to control, in addition to food quality, their possible influence on human health. Because of this, there is a growing demand for rapid, selective, sensitive, and validated methods for analysis and quantification. Bioactive plant compounds include those with weak estrogenic activity (phytoestrogens), among which are the isoflavones. Some of the beneficial activities that have been attributed to isoflavones are anticarcinogenic activity, the prevention of cardiovascular disease, the improvement of bone health, and antioxidant activity. The objective of this work is to provide an updated review of the methods used in sample preparation and subsequent analysis for the determination of isoflavones in food samples, including both soybean and soy products, as well as other foods with low isoflavone contents. The review focuses on the most common sample preparation techniques used during the last 10 years, including both conventional solvent extraction and other more recent extraction techniques. Separation and detection methods, including current trends in liquid chromatography analysis, such as the use of monolithic columns or ultra-high-pressure liquid chromatography, are also discussed.

Comparison of methods for determination of total oil sands-derived naphthenic acids in water samples

There are several established methods for the determination of naphthenic acids (NAs) in waters associated with oil sands mining operations. Due to their highly complex nature, measured concentration and composition of NAs vary depending on the method used. This study compared different common sample preparation techniques, analytical instrument methods, and analytical standards to measure NAs in groundwater and process water samples collected from an active oil sands operation. In general, the high- and ultrahigh-resolution methods, namely high performance liquid chromatography time-of-flight mass spectrometry (UPLC-TOF-MS) and Orbitrap mass spectrometry (Orbitrap-MS), were within an order of magnitude of the Fourier transform infrared spectroscopy (FTIR) methods. The gas chromatography mass spectrometry (GC-MS) methods consistently had the highest NA concentrations and greatest standard error. Total NAs concentration was not statistically different between sample preparation of solid phase extraction and liquid-liquid extraction. Calibration standards influenced quantitation results. This work provided a comprehensive understanding of the inherent differences in the various techniques available to measure NAs and hence the potential differences in measured amounts of NAs in samples. Results from this study will contribute to the analytical method standardization for NA analysis in oil sands related water samples.

A comparison of two common sample preparation techniques for lipid and fatty acid analysis in three different coral morphotypes reveals quantitative and qualitative differences.

Lipids are involved in a host of biochemical and physiological processes in corals. Therefore, changes in lipid composition reflect changes in the ecology, nutrition, and health of corals. As such, accurate lipid extraction, quantification, and identification is critical to obtain comprehensive insight into a coral’s condition. However, discrepancies exist in sample preparation methodology globally, and it is currently unknown whether these techniques generate analogous results. This study compared the two most common sample preparation techniques for lipid analysis in corals: (1) tissue isolation by air-spraying and (2) crushing the coral in toto. Samples derived from each preparation technique were subsequently analysed to quantify lipids and their constituent classes and fatty acids in four common, scleractinian coral species representing three distinct morphotypes (Acropora millepora, Montipora crassotuberculata, Porites cylindrica, and Pocillopora damicornis). Results revealed substantial amounts of organic material, including lipids, retained in the skeletons of all species following air-spraying, causing a marked underestimation of total lipid concentration using this method. Moreover, lipid class and fatty acid compositions between the denuded skeleton and sprayed tissue were substantially different. In particular, the majority of the total triacylglycerol and total fatty acid concentrations were retained in the skeleton (55–69% and 56–64%, respectively). As such, the isolated, sprayed tissue cannot serve as a reliable proxy for lipid quantification or identification in the coral holobiont. The in toto crushing method is therefore recommended for coral sample preparation prior to lipid analysis to capture the lipid profile of the entire holobiont, permitting accurate diagnoses of coral condition.

D.A. Wells: High Throughput Bioanalytical Sample Preparation

Book’s topic The discovery and development of safe and effective new medicines is a long and complex process. Pharmaceutical companies typically invest 9–15 years of research and hundreds of millions of dollars in this effort. With the development of combinatorial chemistry and high-throughput pharmacological testing, the number of new drug candidates to be tested in preclinical drug metabolism has jumped dramatically. In order to screen drug candidates more efficiently in the early stages, cassette dosing and independent dosing of multiple drug candidates in pharmacological, toxicological, and pharmacokinetic studies have become increasingly popular. In these studies, speed of analysis and sample throughput is critical. Especially, sample preparation for biological fluids such as plasma, serum, or urine is rate-limiting. It is, therefore, important to develop a bioanalytical sample-preparation method with high-throughput capability in terms of the number of compounds and samples. The new book ‘‘High Throughput Bioanalytical Sample Preparation’’ provides a wealth of knowledge essential for sample preparation with high throughput (rapid productivity) in the field of drug development, covering a wide range of topics from the fundamental principles of various sample preparation techniques to strategies for method development and automation. Contents and critical assessment The book consists of 15 chapters. It begins with an introductory overview of bioanalysis in pharmaceutical drug development, focusing on activities performed at each stage of drug discovery, preclinical research, clinical development, and regulatory approval. Recent developments and industry trends in rapid sample throughput and data generation are introduced, together with examples of how high throughput needs are being met in bioanalysis. Specific roles of bioanalysis in screening of drug leads, metabolite identification, pharmacokinetics and therapeutic drug monitoring are also discussed. Chapter 2 reinforces the readers’ fundamental understanding of strategies for sample preparation and at the same time gives a preview of subsequent chapters on different techniques available to the bioanalyst. The author enables readers to master knowledge of the available tools needed to perform high-throughput sample-preparation techniques, with introductions and discussions on microplates (Chap. 3), accessory products (Chap. 4) and automation devices (Chap. 5). Selecting and using these high-throughput tools are thoroughly discussed. Particular strategies for efficient use of automation within a bioanalytical laboratory are also presented. The instruments available for automation of bioanalytical applications are discussed in three distinct groups: task-specific devices, liquid-handling workstations operating in a semi-automated or fully-automated mode, and application-specific workstations or systems. Next are reviews of four common sample-preparation techniques: protein precipitation (Chaps. 6 and 7),

The Challenge and Methods of TEM Cross-Sectioning of < 0.25 Micron Plugs

AbstractTransmission electron microscopy (TEM) is a useful tool in process evaluation and failure analysis for semiconductor industries. A common focus of semiconductor TEM analyses is metalization vias (plugs) and it is often desirable to cross-section through a particular one. If the cross-sectional plane deviates away from the center of the plug, then the thin adhesion layer around the plug will be blurred by surrounding materials such as the inter-layer dielectric and the plug material. The importance of these constraints, along with the difficulty of precision sample preparation, has risen sharply as feature sizes have fallen to 0.25 μm and below. The suitability of common sample preparation techniques for these samples is evaluated.

Sources of error in estimating radioactivity in protein from cell cultures by liquid scintillation counting

In this study, several common sample preparation techniques for liquid scintillation counting were critically reviewed. It has been shown that techniques such as NaOH or formic acid solubilization of trichloroacetic acid (TCA)-precipitated proteins led to underestimation of the radioactivity by 20–40%; this loss was not corrected by either internal or external standardization. Hydrolysis of the proteins with 6 n HCl or Pronase significantly increased the recovery of the labeled proteins. Also, 10% of the labeled cell proteins remained on the dish when cells were scraped into buffer; these labelled proteins could be recovered either by in situ hydrolysis with Pronase or by solubilization and scraping in 0.3 n NaOH. These techniques increased the recovered radioactivity by 50–60%, allowing quantitative measurements to be made over a 3-day chase period. A possible mechanism and the implications of this observation were discussed.