Sample Preparation System Research Articles

A New Type of MgFe2O4@CuS-APTES Nanocarrier for Magnetic Targeting and Light-Microwave Dual Controlled Drug Release.

IntroductionCancer is a major health problem worldwide, and the most extensive treatment can be obtained by using chemotherapy in the clinic. However, due to the low selectivity of cancer cells, chemotherapy drugs produce a series of grievous side effects on normal cells.MethodsIn this research, we developed novel nanocarriers for magnetically targeted near-infrared (NIR) light-electromagnetic wave dual controlled drug delivery based on MgFe2O4@CuS nanoparticles (NPs) modified with aminopropyltriethoxysilane (APTES) in response to magnetic, NIR light, and electromagnetic wave irradiation. Synthesis and characterization of MgFe2O4@CuS-APTES NPs was carried out using X-ray diffraction measurements, scanning electron microscopy, transmission electron microscopy, photoluminescence emission spectra, UV-1800 spectrophotometer, N5230A vector network analyzer, MDS-6 microwave sample preparation system, and superconducting quantum interference device. In addition to that mentioned above, we also explored many other sides, such as the drug-loading, drug-controlled release efficiency, elect99omagnetic wave thermal effect and photo-thermal effect.ResultsThe results showed that APTES-modified MgFe2O4@CuS NPs had 37% high drug-loading capacity and high electromagnetic wave thermal conversion ability and NIR-light thermal conversion ability. In addition, ibuprofen (IBU) release from the MgFe2O4@CuS-APTES-IBU depends on the electromagnetic wave (2.45 GHz) and 1060 nm NIR light irradiation. After five cycles, the drug-release percentage was 90% and 66% separately, and could be adjusted by the time and cycles times of electromagnetic wave and NIR light irritation. Electromagnetic wave irradiation compared with NIR light irradiation, has a higher drug release rate and better penetration. Therefore, choosing different stimulation methods according to the treatment needs of the disease, we can achieve accurate personalized treatment of the disease.DiscussionOur findings indicate that multifunctional APTES modified MgFe2O4@CuS NPs could be used for the first time as a new drug carrier for “location-timing-quantification” drug release with magnetic targeting and dual control of NIR light-electromagnetic waves.

Research progress of electrically-driven force based online rapid separation and enrichment techniques

Sample preparation is a critical step in complex sample analysis, which enables analyte isolation and preconcentration from a complex matrix. Therefore, sample preparation is an effective approach to enhance the sensitivity, selectivity, and accuracy of the analytical method. However, the transfer of target analytes from a random state in the original sample matrix to a highly ordered pre-analysis state involves an entropy reduction process that cannot occur spontaneously. Therefore, sample preparation is always a time-consuming, labor-intensive, and error-prone process. Introducing additional energy or reducing the entropy of the system can enhance the separation and enrichment effects as well as accelerate sample preparation. The introduction of an electric field into an online sample preparation system can not only introduce additional energy into the system, but also drive the directional migration of the sample among the separation, enrichment, and detection processes, ensuring that the entropy reduction progresses smoothly. These advantages of electrically-driven force based online separation and enrichment techniques make them effective for accelerating sample preparation. Typically, there are four acceleration strategies in electrically-driven force based online separation and enrichment techniques: (1) the additional energy of the electric field is added into the system to accelerate mass transfer and energy exchange; (2) electrically-driven flows, including electroosmotic flow and electrophoretic flow, are applied to drive the directional migration of the sample among the separation, enrichment, and detection processes, ensuring that sample preparation and analysis are executed smoothly; (3) the online integration technique is applied to enhance the automaticity of the entire sample preparation and analysis processes, and reduce errors from manual operation; (4) device miniaturization or size reduction methods such as microextraction are applied to enhance the sample preparation efficiency and reduce the time consumed. This review summarizes the progress in electrically-driven force based online rapid separation and enrichment techniques in the last ten years. In this specific research area, more than one hundred research papers are published each year, and can be classified into three types based on the electrically-driven force based online rapid separation and enrichment techniques considered: capillary, microchip, and membrane extraction. Among these, over 50% of the studies focused on electrically-driven capillary force based online rapid separation and enrichment techniques. By applying a high-voltage electric field at the two ends of a capillary, charged species in the capillary can migrate along the direction of the medium. This makes the electrically-driven capillary technique not only fast, highly efficient, and low-cost, but also effective for rapid sample preparation. Typically, two modes of electrically-driven capillary force based online rapid separation and enrichment techniques are employed: online capillary electrophoretic separation and enrichment, and online microextraction-capillary electrophoresis. Device miniaturization from the capillary to microchip through microelectronic mechanical systems and microfluidics enables small-amount sample preparation and analysis, and is also advantageous due to being rapid and efficient, as well as low energy- and sample-consuming. The specific easy-integration trait of microchip devices enables the online integration of multi-step sample preparation and analysis. On the other hand, the controllable electrically-driven force can be used for both, directional flow transfer between different functional units in the microchip as well as for dynamic control of the electrically fluid pump and valve. Online microchip electrophoretic separation and enrichment, and online microextraction-microchip electrophoresis, are two common modes of microchip electrically-driven force based online rapid separation and enrichment techniques. In electrically-driven membrane extraction online separation and enrichment techniques, a supporting liquid membrane is used to eliminate the matrix interference, enabling large-scale real sample application. These techniques have received increasing attention in the research area of electrically-driven force based online separation and enrichment. Overall, rapid separation and enrichment techniques are highly desired in complex sample analysis, and electrically-driven force based online approaches offer significant application potential, especially in food, the environment, and medicine.

Stable C isotope data of southern mixed-grass prairie vegetation from Oklahoma, United States.

Stable carbon isotopic data (δ13C) of 41 individual plant species was collected from long-term grazed and ungrazed pastures in Oklahoma, USA. These data can serve as a library of stable carbon isotope values for Southern mixed-grass prairie species. Seventeen warm-season (C4) and twenty-four cool-season (C3) plants were identified and collected from the United States Department of Agriculture (USDA) Southern Plains Experimental Range (SPER). Plant samples were dried at 55°C, and ground finely. The δ13C isotopic compositions were determined using a Europa Scientific automated nitrogen carbon analyzer (ANCA/NT) with a Solid/Liquid Preparation Module (Dumas combustion sample preparation system) coupled to a Europa 20–20 Stable isotope analyzer continuous flow isotope ratio mass spectrometer (Sercon Ltd, formerly Europa Scientific Ltd., Crewe, England). These data can be used as end members in isotopic mixing models or in paleoecology to correlate soil ages with plant species composition. Data from plant species provides information about soil organic carbon sequestration and possible long-term climate change.

LC-ICP-MS method for the determination of "extractable copper" in serum.

Copper is an essential element for biological functions within humans and animals. There are several known diseases associated with Cu deficiency or overload, such as Menkes disease and Wilson disease, respectively. A common clinical method for determining extractable Cu levels in serum, which is thought to be potentially dangerous if in excess, is to subtract the value of tightly incorporated Cu in ceruloplasmin from total serum Cu. In this work, an automated sample preparation and liquid chromatography (LC) system was combined with inductively coupled plasma-mass spectrometry (ICP-MS) to determine bound Cu and extractable Cu in serum. This LC-ICP-MS method took 250 s for sample preparation and analysis, followed by a column recondition/system reset, thus, a 6 minute sample-to-sample time including sample preparation. The method was validated using serum collected from either control (Atp7b+/-) or Wilson disease rats (Atp7b-/-). The extractable Cu was found to be 4.0 ± 2.3 μM Cu in healthy control rats, but 2.1 ± 0.6 μM Cu in healthy Wilson rats, and 27 ± 16 μM Cu in diseased Wilson rats, respectively. In addition, the extractable Cu/bound Cu ratio was found to be 6.4 ± 3.5%, 38 ± 29%, and 34 ± 22%, respectively. These results suggest that the developed method could be of diagnostic value for Wilson disease, and possibly other copper related diseases.

Abstract 5368: A multiparameter assay for HER2 protein detection on circulating tumor cells in non-small cell lung cancer

Abstract Lung cancer biopsy can be difficult to perform successfully; it has a 30% adverse event risk and often provides insufficient material to test. Therefore, a liquid biopsy method to analyze the tumor is advantageous. Analysis of circulating tumor cells (CTCs) by multiparameter immunofluorescence (IF) microscopy allows non-invasive characterization of cancer cell biomarker expression. HER2 is a well-known therapeutic target in breast cancer and studies have shown that HER2 status on CTCs may provide prognostic information about response to anti-HER2 therapies. Less is understood about its frequency and clinical importance in non-small cell lung cancer (NSCLC). The RareCyte platform is uniquely suited for CTC identification and phenotypic characterization with a sensitive, accurate, simple and repeatable workflow from blood collection to CTC characterization and single-cell isolation. We developed an assay for detecting HER2 expression on lung CTCs using the RareCyte platform and validated the assay on model CTC spike-in samples with high (BT-474), medium (MDA-MB-453), low (H1650 and OVCAR-3) and absent (MDA-MB-468) HER2 protein levels. Blood was processed to slides using the AccuCyte Sample Preparation System and stained with anti-HER2 together with the RarePlex Kit for CTC identification (nuclear dye, anti-CD45 to exclude WBC, and anti-cytokeratin/EpCAM for CTCs). The spike-in samples showed the expected trend in per-cell HER2 mean fluorescence intensity values. The percentage of HER2-positive cells was > 90% for the HER2-high, medium and low cell lines, and < 5% for the HER2-negative cell line. The assay was applied to 10 advanced stage (III or IV) post-treatment NSCLC patient samples. At least 1 CTC was found in 6 samples (range 0-2043) and HER2 expression was confirmed in 5 out of the 6 samples, indicating this assay is useful for characterizing HER2 expression in CTCs in NSCLC. Citation Format: Edward Lo, Daniel Campton, Lillian Costandy, Heather Itamoto, Ryan Huston, Braden Gardner, Steve Reese, Arturo Ramirez, Eric P. Kaldjian, Tad George, I-Ming Wang, Steven Pirie-Shepherd. A multiparameter assay for HER2 protein detection on circulating tumor cells in non-small cell lung cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5368.

Abstract 5384: Analytic validation of an assay to detect androgen receptor splice variant ARv7 protein expression on circulating tumor cells from prostate cancer patients

Abstract Circulating tumor cells (CTCs) can provide information on drug target expression, response to therapy, and disease prognosis from a non-invasive blood draw. Currently, investigating biomarkers on CTCs is difficult due to challenges of developing multiplexed assays that also identify rare cells. Presence of the androgen receptor splice variant ARv7 in prostate cancer cells is associated with resistance to second generation anti-androgen therapies. We report here the analytical validation of an immunofluorescence assay for characterization of ARv7 protein expression on CTCs using the RareCyte platform - an end-to-end platform that combines CTC sample preparation, multiparameter fluorescence staining, digital imaging, and single cell retrieval. Blood samples spiked with positive and negative cell lines for ARv7 expression were processed using the AccuCyte Sample Preparation System. Slides were auto-stained by immunofluorescence with the RarePlex ARv7 CTC Panel Kit comprised of a three-channel CTC detection base plus an ARv7 biomarker channel. The detection base consists of a nuclear dye, anti-CD45 antibody to exclude white blood cells, and cocktailed antibodies to cytokeratin (CK) and epithelial cell adhesion molecule (EpCAM). Stained slides were imaged with the CyteFinder Instrument. CTCs were identified using machine learning-based algorithms and confirmed by user review. Mean fluorescence intensity (MFI) measurements were used as a metric for ARv7 expression on confirmed CTCs. Analytic validation studies of the AR-V7 CTC assay were performed using 22RV1 (high), LNCaP (low), and BT-474 (negative) cell lines. Performance characteristics tested for ARv7 included accuracy, sensitivity, specificity, repeatability, and inter-stainer run coefficient of variation. Performance metrics for CTC recovery were calculated on spike-in and clinical samples. For recovery calculations, the number of CTCs found with the ARv7 assay was compared to the number of CTCs found with the CTC detection base assay. An ARv7 MFI threshold that segregated negative and positive cell lines was statistically defined. This threshold identified 80% of 22RV1 cells as positive for ARv7, 97% of BT-474 cells as negative, with an overall accuracy of 90%. When the assay was applied to clinical prostate cancer samples, staining with proper nuclear localization was observed. CTC recovery was at least as high with the ARv7 assay as with the base CTC detection assay. Citation Format: Daniel Campton, Edward Lo, Lillian Costandy, Brady Gardner, Ryan Houston, Jeffery L. Werbin, Kyla Teplitz, Daniel E. Sabath, Alisa C. Clein, Celestia S. Higano, Tanisha M. Mojica, Kristin Province, Eric P. Kaldjian, Arturo B. Ramirez, Tad George. Analytic validation of an assay to detect androgen receptor splice variant ARv7 protein expression on circulating tumor cells from prostate cancer patients [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5384.

Cannabidiol Determination on Peripheral Capillary Blood Using a Microsampling Method and Ultra-High-Performance Liquid Chromatography Tandem Mass Spectrometry with On-Line Sample Preparation.

The aim of this work is to evaluate volumetric absorptive microsampling (VAMS) from capillary blood as an alternative strategy for therapeutic drug monitoring (TDM) in patients treated with the newly available GW-purified form of cannabidiol (Epidiolex®). A fast ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) coupled to an online sample preparation system analysis was carried out on a Thermo Scientific Ultimate 3000 LC system coupled to a TSQ Quantiva triple quadrupole for the quantification of cannabidiol (CBD) and, in addition, delta-9-tetrahydrocannabinol (Δ9-THC). After validation using European Medicine Agency (EMA) guidelines the method was applied to samples obtained by finger prick of five pediatric patients treated with Epidiolex® and the results were compared to those obtained from venous blood and plasma. The method is linear in the range of 1–800 µg/L for both CBD and THC with intra- and inter-day precisions ranging from 5% to 14% and accuracies from −13% to +14% starting from 30 µL of sample. Stability in VAMS is ensured for up to 4 weeks at 25 °C thus allowing simple delivery. There was no difference (p = 0.69) between concentrations of CBD measured from VAMS sampled from capillary or venous blood (range: 52.19–330.14 or 72.15–383.45 µg/L) and those obtained from plasma (range: 64.3–374.09 µg/L) The VAMS-LC-MS/MS method represents a valid alternative strategy for therapeutic drug monitoring of patients treated with Epidiolex®.

Lab-In-Syringe for automated double-stage sample preparation by coupling salting out liquid-liquid extraction with online solid-phase extraction and liquid chromatographic separation for sulfonamide antibiotics from urine

A double-stage Lab-In-Syringe automated extraction procedure coupled online to HPLC for the determination of four sulfonamides in urine has been developed. Our method is based on homogeneous liquid-liquid extraction at pH 3 using water-miscible acetonitrile with induction of phase separation by the addition of a saturated solution of kosmotropic salts MgSO4 and NaCl. The procedure allowed extraction of the moderately polar model analytes and the use of a solvent that is compatible with the used separation technique. The automated sample preparation system based on the stirring-assisted Lab-In-Syringe approach was coupled on-line with HPLC-UV for the subsequent separation of the sulfonamide antibiotics. To improve both preconcentration factor and extract cleanup, the analytes were trapped at pH 10 in an anion-exchange resin cartridge integrated into the HPLC injection loop thus achieving a double-stage sample clean-up. Analytes were eluted using an acidic HPLC mobile phase in gradient elution mode. Running the analytes separation and the two-step preparation of the following sample in parallel reduced the total time of analysis to mere 13.5 min. Limits of detection ranged from 5.0 to 7.5 μg/L with linear working ranges of 50–5000 μg/L (r2 > 0.9997) and RSD ≤ 5% (n = 6) at a concentration level of 50 μg/L. Average recovery values were 102.7 ± 7.4% after spiking of urine with sulfonamides at concentrations of 2.5 and 5 mg/L followed by 5 times dilution. To the best of our knowledge, the use of Lab-In-Syringe for the automation of coupled homogeneous liquid-liquid extraction and SPE for preparation of the complex matrices suitable for separation techniques is here presented for the first time.

Flow-Batch Sample Preparation for Fractionation of the Stress Signaling Phytohormone Salicylic Acid in Fresh Leaves.

Salicylic acid (SA) is an important stress signaling phytohormone and plays an essential role in physiological processes in plants. SA fractionation has been carried out batchwise, which is not compatible with the high analytical demand in agronomical studies and increases susceptibility to analytical errors. In this context, a novel flow-batch sample preparation system for SA fractionation on fresh plant leaves was developed. It was based on microwave-assisted extraction with water and conversion of the conjugated species to free SA by alkaline hydrolysis. Free and total SA were quantified by fluorimetry after separation by sequential injection chromatography in a C18 monolithic column. The proposed procedure is directly applicable to plant leaves containing up 16 mg kg−1 SA, with a limit of detection of 0.1 mg kg−1 of SA, coefficient of variation of 3.0% (n = 10), and sampling rate of 4 samples h−1. The flow-batch sample preparation system was successfully applied to SA fractionation in sugarcane, corn, and soybean leaves without clogging or increasing in backpressure. The proposed approach is simple, less time-consuming, and more environmentally friendly in comparison to batchwise procedures.

IQuant Auto: Automated Rapid Test Platform for Immunodiagnostics.

Point-of-care diagnostic devices aid in the early and rapid detection of immunological markers leading to better medical outcomes. Lateral flow immunoassays (LFIA) are fast assays that provide both qualitative and semi-quantitative results on site. Sample preparation for LFIA tests is usually done manually with multiple mixing steps and is prone to errors. The iQuant Auto is an entirely automated system that can handle sample preparation, effective transfer to lateral flow test membrane, and subsequent result estimation. The system uses a pneumatic system for fluid handling and sample preparation, and an image-based fluorescence reader for reaction visualization. The device works with test specific milli-fluidic lateral flow kit called iQPrep Kit, which has integrated reagent storage areas and valves for fluid control. The test kit can be manufactured using standard manufacturing techniques and can be produced at scale cheaply. The iQPrep Kit can be modified to test for various markers like HbA1c, Vitamin D, and TSH, while the hardware for sample preparation and the fluorescence reader remains the same. The device has a minimalist and intelligible graphical interface aiding smooth operation by less skilled people at resource-limited settings. Standard reference cartridges of different volume ratios were used to validate the functionality of the instrument. The intra- instrument coefficient of variation (CoV) of the mobile kit reader was found to be less than 0.62%. The positional accuracy of the system to ensure precise kit engagement with the other auxiliary systems was checked, and the CoV was 0.16%. The fluid handling capabilities were tested, and it was found that an average fluid loss of 10 µl results due to the liquid adherence to fluid channel walls and valve interfaces. The iQuant Auto is an easily operable, total analysis system for immunodiagnostics.

Sensitive Top-Down Proteomics Analysis of a Low Number of Mammalian Cells Using a Nanodroplet Sample Processing Platform.

Top-down proteomics is a powerful tool for characterizing genetic variations and post-translational modifications at intact protein level. However, one significant technical gap of top-down proteomics is the inability to analyze a low amount of biological samples, which limits its access to isolated rare cells, fine needle aspiration biopsies, and tissue substructures. Herein, we developed an ultrasensitive top-down platform by incorporating a microfluidic sample preparation system, termed nanoPOTS (nanodroplet processing in one pot for trace samples), into a top-down proteomic workflow. A unique combination of a nonionic detergent dodecyl-β-d-maltopyranoside (DDM) with urea as protein extraction buffer significantly improved both protein extraction efficiency and sample recovery. We hypothesize that the DDM detergent improves protein recovery by efficiently reducing nonspecific adsorption of intact proteins on container surfaces, while urea serves as a strong denaturant to disrupt noncovalent complexes and release intact proteins for downstream analysis. The nanoPOTS-based top-down platform reproducibly and quantitatively identified ∼170 to ∼620 proteoforms from ∼70 to ∼770 HeLa cells containing ∼10 to ∼115 ng of total protein. A variety of post-translational modifications including acetylation, myristoylation, and iron binding were identified using only less than 800 cells. We anticipate the nanoPOTS top-down proteomics platform will be broadly applicable in biomedical research, particularly where clinical specimens are not available in amounts amenable to standard workflows.

Insulin-like growth factor-1 receptor (IGF-1R) expression on circulating tumor cells (CTCs) and metastatic breast cancer outcome: results from the TransMYME trial.

To evaluate the prognostic value of IGF-1R expression on circulating tumor cells (CTCs) in a prospective randomized clinical trial comparing chemotherapy plus metformin with chemotherapy alone in metastatic breast cancer (MBC) patients. CTCs were collected at baseline and at the end of chemotherapy. An automated sample preparation and analysis system (CellSearch) were customized for detecting IGF-1R expression. The prognostic role of CTC count and IGF-1R was assessed for PFS and OS by univariate and multivariate analyses. Seventy-two out of 126 randomized patients were evaluated: 57% had ≥ 1 IGF-1R positive CTC and 37.5% ≥ 4 IGF-1R negative cells; 42% had CTC count ≥ 5/7.5ml. At univariate analysis, the number of IGF-1R negative CTCs was strongly associated with risk of progression and death: HR 1.93 (P = 0.013) and 3.65 (P = 0.001), respectively; no association was detected between number of IGF-1R positive CTCs and PFS or OS (P = 0.322 and P = 0.840). The prognostic role of CTC count was confirmed: HR 1.69, P = 0.042 for PFS and HR 2.80 for OS, P = 0.002. By multivariate analysis, the prognostic role of the number of IGF-1R negative CTCs was maintained, while no residual prognostic role of CTC count or number of IGF-1R positive cells was found. Loss of IGF-1R in CTCs is associated with a significantly worse outcome in MBC patients. This finding supports further evaluation for the role of IGF-1R on CTCs to improve patient stratification and to implement new targeted strategies. Clinicaltrials.gov (NCT01885013); European Clinical Trials Database (EudraCT No.2009-014,662-26).

A lathe system for micrometre-sized cylindrical sample preparation at room and cryogenic temperatures

A simple two-spindle based lathe system for the preparation of cylindrical samples intended for X-ray tomography is presented. The setup can operate at room temperature as well as under cryogenic conditions, allowing the preparation of samples down to 20 and 50 µm in diameter, respectively, within minutes. Case studies are presented involving the preparation of a brittle biomineral brachiopod shell and cryogenically fixed soft brain tissue, and their examination by means of ptychographic X-ray computed tomography reveals the preparation method to be mainly free from causing artefacts. Since this lathe system easily yields near-cylindrical samples ideal for tomography, a usage for a wide variety of otherwise challenging specimens is anticipated, in addition to potential use as a time- and cost-saving tool prior to focused ion-beam milling. Fast sample preparation becomes especially important in relation to shorter measurement times expected in next-generation synchrotron sources.

Gas chromatographic determination of phenols in surface waters using polyoxyethylene bis arsenates

Current paper is devoted to the determination of phenols in surface waters using the method of gas-liquid chromatography on the nozzle chromatographic columns with different polarities of sorbents, in the capacity of which silicone elastomers, polyethylene glycol with the molecular weight of 1500, and polyoxyethylene bis arsenate obtained by arsenating polyethylene glycol-1500 were studied. It was shown that positional isomers, para - and meta – cresols, which have almost identical boiling points, were separated on polyoxyethylene bis arsenate and on the standard sorbents (SE-30 and PEG-1000) they practically do not separate and come out with a single peak. The logarithmic retention indexes were determined for the analyzed phenols and chromatographic Rorschneider polarity factors on polyoxyethylene bis arsenate, which are extremely high for ethanol (factor y) and are associated with the formation of an intermolecular hydrogen bond in the sorbate-sorbent system. It was found that polyoxyethylene bis arsenate had a linear dependence of the logarithm of the retention time on their boiling point and dipole moments. In the case of dipole moments, there was a deviation from the specified dependence for o-chlorophenol, obviously as a result of a specific substituent effect (ortho effect). Polyoxyethylene bis arsenate was used to determine phenols in the surface waters of the Kuibyshev reservoir. For this purpose, a sample preparation system based on the conversion of phenols into brominated derivatives, which have high volatility and are fairly well analyzed by gas-liquid chromatography, was used. A comparative characteristic of the limit of detection of phenols for flame ionization and thermionic detectors was given. As a result of the determination of phenols in the surface waters of the Kuibyshev reservoir, a high content of phenols was found, which fluctuates during the different seasons of the year.

Recent Progress in Fast Sample Preparation Techniques.

Sample preparation is a critical step in complex sample analysis which effect to sensitivity, selectivity, speed, and accuracy of analytical results. The goal of sample preparation is separation and enrichment. Separation and enrichment are entropy reduction procedures which cannot happen spontaneously. On account of consuming over two thirds of analysis time, sample preparation becomes the bottleneck issue in analytical chemistry. Therefore, fast sample preparation has been received much attention. In this review, a comprehensive survey on progress in fast sample preparation techniques for complex sample in the last 2 years has been composed from more than 180 references. Four approaches for entropy reduction of sample preparation system were generalized, they are energy exchange acceleration, materials-based acceleration, size reduction acceleration, and integration acceleration. Moreover, we highlight the most interesting acceleration techniques, including field-assisted, materials-based rapid mass tra...

One Pot Cooking of Rice Grains for Preparation of Rice-Gel Samples Using a Small-Scale Viscosity Analyzer: Small-scale Rice-gel Preparation from Grains.

Rice-gel prepared by the following three steps: rice grain cooking, shearing of the cooked rice, and cooling for gel formation, is expected as a novel food ingredient for modification of various food products such as bread and noodles. To meet the demand for high-throughput systems for research and developments on the new rice gels, herein we established a mini-cooking system for preparation of rice gel samples from grains using a small-scale viscosity analyzer (Rapid Visco Analyzer; RVA). Polished rice grains (4 g) were cooked with 22 mL of water in a canister, and the paddle equipped in the canister was rotated at 2,000 rpm for 30 min (80 °C was used as a representative) to shear the cooked rice. The sheared paste was cooled to 10 °C at 160 rpm, and the initial gelation property was evaluated by viscosity analysis within the RVA. Alternatively, the sheared paste was transferred to an acrylic mold and kept at 4 °C for 0, 1, 3, and 5 days for determination of the hardness with a compression test. Compressive forces required to penetrate 20 % thickness for three tested rice cultivars were measured, and the trend of the value shifts during preservation is similar to the corresponding trend obtained in 300-g grain scale laboratory tests, whereas the individual values were halved in the former. This small cooking method could offer a useful assay system for a rapid evaluation in the breeding programs and in the high-throughput screening of additives for the modification of properties.

A robust, hand-powered, instrument-free sample preparation system for point-of-care pathogen detection

Here, we describe a simple, universal protocol for use in nucleic acid testing-based pathogen diagnostics, which requires only hand-powered sample preparation, including the processes of pathogen enrichment and nucleic acid isolation. The protocol uses low-cost amine-functionalized diatomaceous earth with a 1-μm Teflon filter as a reaction matrix in both stages of the process, using homobifunctional imidoesters. Using a simple syringe as a pump, the capture efficiency for a large sample volume (<50 mL) was enhanced by up to 98.3%, and the detection limit was 1 CFU/mL, 100-fold better than that of common commercial nucleic acid isolation kit. This protocol can also be combined with commercialized 96-well filter plates for robust sample preparation. Our proposed system is robust, simple, low-cost, universal, and rapid (taking <20 min), and it works regardless of the ambient environment and sample pretreatment, requiring no electricity or instruments. Its benefits include the simplicity of producing its components and its ease of operation, and it can be readily integrated with other assays for point-of-care diagnostics.

Cold finger with semi closed reflux system for sample preparation aiming at Al, Ca, Cr, Cu, Fe, K, Mg, Mn, Ni, V and Zn determination in Drinking Water Treatment Sludge by MIP OES

This study presents method development and optimization, based on statistical approaches, of an alternative sample preparation methodology for Drinking Water Treatment Sludge, through decomposition in semi closed system with cold finger, aiming at the determination of Al, Ca, Cr, Cu, Fe, K, Mg, Mn, Ni, V and Zn by microwave induced plasma optical emission spectrometry. This system was employed to decompose three different Drinking Water Treatment Sludge samples, from three different treatment plants. The compromise conditions were 250 mg of dried sample, 5 mL of HNO3, 1 mL of H2SO4 and heating at 225 °C for 150 min. After the digestion, 1% of cesium and lanthanum chloride buffer solution was added to all samples and standard solutions. The accuracy of the proposed sample preparation method was evaluated by analyzing a sediment certified reference material (CRM NIST 1646a) as well as the spike recovery technique. The recoveries ranged from 83% to 119% for all elements, and the found concentrations for the CRM agreed with the respective certified values, at 95% confidence level. The correlation coefficients for all investigated elements were higher than 0.999. The method LOQ values were adequate and complied with the Drinking Water Treatment Sludge regulation avaliable, ranging from 0.3 (V) and 32 (Zn) μg L−1, or 0.1 (V) to 13 (Zn) mg kg−1. The digestion procedure in acidic medium showed suitable to measure the analytes in the investigated matrix by microwave induced plasma optical emission spectrometry.

Radiocarbon dating of Chinese Ancient Tea Trees

ABSTRACTThe jungles of Linyun and Longlin Autonomous Prefecture, located in the heart of the southwestern Guangxi Zhuang Autonomous Region of China, are home to the oldest tea trees (Camellia sinensis) in the world. In the absence of regular annual rings, radiocarbon (14C) dating is one of the most powerful tools that can assist in the determination of the ages and growth rates of these plants. In this work, cores were extracted from large ancient tea trees in a central Longlin rain forest; extraction of carbon was performed with an automated sample preparation system. The 14C levels in the tree cores were measured using accelerator mass spectrometry (AMS) at the University of Tsukuba. These measurements indicated that contrary to conventional views, the ages of trees in these forests range up to ~700 years, and the growth rate of this species is notably slow, exhibiting a long-term radial growth rate of 0.039±0.006 cm/yr. It was demonstrated that 14C analyses provide accurate determination of ages and growth rates for subtropical wild tea trees.

Accelerating sample preparation of graded thermoelectric materials using an automatic powder feeding system

In recent years, the development of techniques for the controlled preparation of functional graded materials (FGMs) has become a vigorous research field. In this study, to improve the efficiency and accuracy of sample preparations, an automated feeding system based on gravimetric principles for dry powder with three dosing feeders is designed and realized. The feeding rate and accuracy can be regulated by coordinating the protruded length L (mm) and rotational speed V (r/min) of the feeder stirrer. To demonstrate this automatic sample preparation system, the well-known thermoelectric material BixSb2−xTe3 (x = 0.3, 0.4, 0.5, 0.6, 0.7 and 0.8) is selected and prepared by the developed system, and the composition distribution of the functional graded material is characterized. Experimental results show that the BixSb2−xTe3 (x = 0.3–0.8) functionally graded material crystalizes in the rhombohedral phase after hot-pressing sintering and annealing and the prepared sample has a good gradient composition distribution. This verifies the reliability and accuracy of the feeding system. The concept of samples with a gradient component and application of the automatic powder feeding system could considerably accelerate the research and development of new materials.