Fast Separation Method Research Articles

Fast engine noise sources separation based on short-time segmentation method

Cyclic Wiener filtering method (CWFM) has been widely used in engine noise sources separation but it is extremely time-consuming. In order to improve the efficiency, this paper proposes a fast separation method of engine noise sources based on the short-time segmentation method. In this method, signals from the acceleration condition are discretized into a large number of short-time signal segments to replace the steady-state conditions to separate engine noise sources at all speeds. The prerequisites for the short-time stationary assumption of the signal under acceleration condition are studied through experiments. The cylinder pressure-dependent noise (CPDN) separated by the fast separation method has been proven to have high precision through an experiment of accelerated condition under a load near zero. This method is used for noise sources separation of a diesel engine. It only needs to repeat the uniform acceleration several times for each load and the engine noise in all operating conditions can be separated into CPDN, load-dependent noise (LDN) and mechanical noise (MN). The result initially indicates the optimization direction of the engine noise. In addition, CWFM can be used to further separate the combustion noise in the operating conditions where the CPDN is prominent. The engine noise sources can be separated efficiently and accurately by maximizing the advantages of these two methods.

Independent deeply learned matrix analysis with automatic selection of stable microphone-wise update and fast sourcewise update of demixing matrix

Independent deeply learned matrix analysis (IDLMA) is a fast and high-performance method for multichannel audio source separation. IDLMA utilizes the deep neural network inference of source models and the blind estimation of demixing filters based on source independence. In conventional IDLMA, iterative projection (IP) is exploited to estimate the demixing filters. Although IP is a fast algorithm, it sometimes fails to estimate an appropriate solution. This is because IP updates the demixing filters in a sourcewise manner, where only one source model is used for each update, and the update sometimes becomes unstable owing to the specific low-quality source models. In this paper, we first derive a new numerically stable microphone-wise update algorithm that exploits all source model information simultaneously. The microphone-wise update problem cannot be solved by IP; instead, a new type of vectorwise coordinate descent algorithm is introduced. Next, comparison analysis of the proposed microphone-wise update and IP reveals the tradeoff w.r.t. convergence speed and numerical stability. To resolve this tradeoff problem, we propose the automatic selection of update rules on the basis of the likelihood function of observed signals. Finally, experimental results show the efficacy of the proposed IDLMA with the automatic selection of update rules.

Feasible oxidative degradates separation with instant quantification of two non-classical β-lactams by derivative UV spectrophotometry and TLC densitometry

The present paper focuses on the study of stability of two non-classical β-lactam drugs, namely meropenem (MP) and ertapenem (EP) that are highly susceptible to degradation. We proposed two facile and accurate derivative UV spectrophotometric and TLC densitometric methods for fast separation of MP and EP from their oxidative degradates. Firstly, first derivative (D1) and derivative ratio (DR1) techniques were successfully implemented at 325, 324 nm and 322, 320 nm, respectively. Secondly, TLC densitometry was apparently applied at 254 nm, utilizing 2-propanol–methanol–water as a developing system. Oxidative degradation is elucidated by infrared and mass spectrometry. Both developed methodologies aided to determine MP and EP in pure forms, prepared mixtures with oxidative degradates and pharmaceutical vials. Validation was performed in accordance with USP guidelines. Despite both derivative techniques attained the same sensitivity, DR1 method advantageously improved the selectivity by tenfold than D1. All methods considered stability, indicating to oxidative degradation. Statistical comparison and single-way ANOVA emphasized insignificant differences among suggested methods with other referenced ones. Multiple privileges were encountered in UV spectrophotometric and TLC densitometric methods because no sophisticated handling, minimal solvent consumption, no prior separation stages, easiness and wide implementation in QC laboratories of limited budget levels.

Research progress on core-shell silica stationary phases for high performance liquid chromatography

Fast and efficient separation by using high performance liquid chromatography (HPLC) is challenging for a wide range of samples. In recent years, core-shell silica microspheres have been widely investigated and used for highly efficient and fast separation under reasonably low pressure for small solutes, biopolymers, and complex samples. In this paper, the mechanism for fast separation and preparation methods of core-shell silica microspheres are introduced, along with their application for HPLC-based separation of small molecules, peptides, and biological macromolecules in HPLC. The developing trends of using core-shell microspheres in HPLC are also presented.

Fast and Ecological Liquid-Liquid Separation Method for Preparing Quinones Enriched Extract from Nigella sativa Oil

A fast, inexpensive, and ecological method based on liquid-liquid extraction principle has been developed for preparation of extract with high content of Nigella sativa (N. sativa) quinones. The gas chromatography-mass spectrometry (GC-MS) analysis showed that oil extraction using 70% ethanol for 6 h yielded extract containing 50% of thymoquinone (TQ) and 13% of thymohydroquinone (THQ).

Synthesis and optimization of SiO2@SiO2 core-shell microspheres by an improved polymerization-induced colloid aggregation method for fast separation of small solutes and proteins

Recently, superficially porous particles (SPPs) have been intensively studied and employed for highly efficient and fast separations. In this paper, the SiO2@SiO2 SPPs were synthesized by an improved polymerization-induced colloid aggregation (PICA) method using urea-formaldehyde polymer as the template. The agglomeration of silica core during modification with ureidopropyltrimethoxysilane (UPS) can not only be avoided by reflux in neutral ethanol solution, but also the secondary nucleation of the colloidal silica sol can be inhibited via optimizing the reaction conditions including pH, temperature, colloidal silica sol concentration and the reaction time. The shell thickness and pore size of SPPs can be controlled successfully by adjusting the weight ratio of silica core/colloidal silica sol and the particle size of colloidal silica sol, respectively. The SPP-C18 columns packed using octadecyltrichlorosilane (ODS) modified SPPs with different pore sizes were employed to separate small solutes and proteins. The baseline separations of 6 kinds of alkyl benzenes and 5 kinds of aromatic alcohol homologues were achieved within 4 min by the SPP-C18 column with 8 nm pore size. Compared with the commercial BEH-C18 column, more than 50,000/m of the plate number of propylbenzene was obtained, and the former provided higher column efficiency to separate small solutes than the latter. Meanwhile, 6 kinds of proteins were also separated completely within 2 min using the SPP-C18 column with 40 nm pore size. In addition, the SPP-C18 capillary column was applied to separate and identify the BSA/HeLa/mouse liver digests with capillary LC-MSMS, respectively. The results indicate that more proteins and peptides can be identified using SPP-C18 capillary column compared with commercial silica-C18 capillary column. The result demonstrates that the prepared SPP-C18 column provides higher column efficiency and the SPPs synthesized with the improved PICA method shows a great potential application for the fast separation of small solutes and proteins.

Dispersive liquid–liquid microextraction based on green type solvents—"deep eutectic solvents"—for highly selective separation and efficient preconcentration of nickel in water samples

This study proposed a fast, feasible, and sensitive method for nickel preconcentration and separation in different actual samples through the use of deep eutectic solvent based dispersive liquid–liquid microextraction (DES-DLLME). This method involves dissolving a suitable extraction solvent in a dispersive solvent and its rapid syringing into water sample to obtain a turbid solution. Phase separation could be then carried out by centrifugation and the analyte can be determined. 2,2′-furildioxime was employed as the chelating agent through formation of a hydrophobic complex with nickel. To reach maximum recovery, some variables including type and volume of dispersive solvent, volume of extraction solvent, pH, 2,2′-furildioxime concentration, and salt concentration were optimized. Under optimal conditions, nickel calibration graph was linear in the range of 5.0–100 µg L−1. The detection limit and preconcentration factor were obtained as 1.7 µg L−1 and 40 µg L−1, respectively. Finally, this method was successfully applied for the extraction and determination of nickel in water samples with a relative recovery of 98.8–101.0%.

Activated Sludge Biomass as Magnetic Biosorbent

Background. Heavy metal pollution is a typical issue for a number of industries, and their removal is crucial for the environmental ecology. Biomass can be used as cheap and eco-friendly sorbent, for example excess activated sludge, because its utilization is a major expense in water treatment. Sorbents with magnetic properties can be extracted using fast and efficient magnetic separation method. Mechanism of biomineralization biogenic magnetic nanoparticles (BMN) is proved to be general for all three domains, so it is important to study what amount of activated sludge microorganisms are potential BMN producents. Objectives. The objective of this study is to determine potential BMN producents among microorganisms of activated sludge using methods of comparative genomics, to obtain magnetic biosorbent and investigate its efficiency in Fe 2+ removal from FeSO 4 solution (500 mg/L). Methods. For estimating homologies between biomineralization proteins of Μ agnetospirillum gryphiswaldense MSR-1 and microorga­nisms of activated sludge were used methods of pairwise and multiple genomic sequence alignment using free access tool BLAST (National Centre for Biotechnological Information, USA). For obtaining magnetic sorbent from activated sludge biomass high gradient magnetic separation was used. Results. Bioinformatic analysis showed, that among studied microorganisms of activated sludge, whose genomes are sequenced per 25% and more, all appeared to be potential BMN producers ( Stentor coeruleus , Bodo saltans , Sphaerotilus natans , Beggiatoa alba B18LD, Oscillatoria acuminata PCC 6304, Oscillatoria sp. PCC 10802, Oscillatoria nigro-viridis PCC 7112, Rivularia sp. PCC 7116, Anabaena sp. CRKS33, Anabaena sp. WA113, Anabaena sp. AL93, Anabaena sp. PCC7108, Anabaena MDT 14b, Thiothrix nivea DSM 5205, Duganella zoogloeoides ATCC 25935), 12 of them – potential producents of intracellular crystalline BMN. It was shown, that Fe 2+ removal efficiency isequal for non-separated activated sludge and both magnetic and non-magnetic fractions. Conclusions. Results show that excess sludge biomass can be used to obtain magnetic sorbent, which can be made without the use of extra magnetization with artificial magnetic nanoparticles. This allows extracting sorbent using methods of high gradient magnetic separation. Sorption results of Fe 2+ for magnetically labelled biosorbent on the base of activated sludge microorganisms experimentally proves equal efficiency of magnetically labelled, non-labelled fractions and biomass which was not exposed to HGMS and is higher than 97%.

Determination of Hormone Antagonists in Waste-Water Samples by Micellar Electrokinetic Chromatography

The contamination of water represents a major problem in many parts of the world. Endocrine disrupting compounds belong to the water contaminants and affect, besides other things, hormonal equilibrium in the living organisms. Such compounds are of different chemical structures and there is a demand for their fast determination in water samples. In our work, we focused on the development of a simple and fast method for separation and determination of five model hormone antagonists, exemestane, toremifene, letrozole, anastrozole, and mifepristone, by micellar electrokinetic chromatography. Within the best conditions, 50 mM sodium borate pH 9.5, 50 mM SDS, 15% 1-propanol, 20 kV, the separation of all the compounds lasted 8 min. The method was successfully validated with LODs of 1.2–7.7 µg mL−1, LOQs of 4.0–25.6 µg mL−1 and intraday repeatability of peak areas of 0.8–1.1%. Moreover, it was applied to the analysis of spiked water samples from a local waste-water treatment plant using SPE as a pretreatment step.

A Fast Separation Method for Isotope Analysis Based on Compressed Nitrogen Gas and Ion-Exchange Chromatography Technique—A Case Study of Sr-Nd Isotope Measurement

High-purity N2 was used to increase the mobile phase flow rate during ion purification of ion-exchange resin. This was performed to improve the efficiency of isotope separation and purification, and to meet the efficiency requirements of rapid multiple-collector-inductively coupled plasma mass spectrometry (MC-ICPMS) analysis. For Cu isotope separation, our results indicated that at a gas flow rate >60 mL/min, the separation chromatographic peaks broadened and the recovery rate decreased to 99.9%. The Cu isotope ratio, measured by the standard-sample bracketing method, agreed with reference data within a ±2 SD error range. The separation time was reduced from the traditional 10 h (without N2) to 4 h (with N2), indicating that the efficiency was more than doubled. Moreover, Sr and Nd isotope separation in AGV-2 (US Geological Survey andesite standard sample) accelerated with a 20 mL/min gas flow, demonstrating that with the passage of N2, the purified liquid comprised Rb/Sr and Sm/Nd ratios of <0.000 049 and <0.000 001 5, respectively. This indicated an effective separation of Rb from Sr and Sm from Nd. MC-ICPMS could therefore be applied to accurately determine Sr and Nd isotope ratios. The results afforded were consistent with the reference data within a ±2 SD error range and the total separation time was shortened from 2 d to <10 h.

Submicrometer-sized nonspherical particle separation by laser beam.

The radiation pressure exerted on sub-micrometer-size particles is shown to be an important factor predetermining the impact coordinates of the particles after being illuminated by a laser beam. Unlike spherical particles, the nonspherical ones can be deflected perpendicularly to the beam direction if the momentum transfer from the laser beam to a particle is large enough. Such an optical sorting is a useful technology, which can be used to isolate spherules of a specific size from a population of particles of random sizes and shapes. The system of ideal spheres has a wide range of applications in industry and also in the development of targeted optical devices, and so the methods for fast contact-less particle separation are expected to lead to considerable progress in the field. The theoretical model we have developed is demonstrated in a set of numerical experiments on metallic and nonmetallic particles.

An improved method for fast and selective separation of carotenoids by LC-MS.

Carotenoids are a large class of compounds that are biosynthesized by condensation of isoprene units in plants, fungi, bacteria, and some animals. They are characteristically highly conjugated through double bonds, which lead to many isomers as well susceptibility to oxidation and other chemical modifications. Carotenoids are important because of their potent antioxidant activity and are the pigments responsible for color in a wide variety of foods. Human consumption is correlated to many health benefits including prevention of cancer, cardiovascular disease, and age-related disease. Extreme hydrophobicity, poor stability, and low concentration in biological samples make these compounds difficult to analyze and difficult to develop analytical methods for aimed towards identification and quantification. Examples in the literature frequently report the use of exotic stationary phases, solvents, and additives, such as ethyl acetate, dichloromethane, and methyl tert-butyl ether that are incompatible with liquid chromatography mass spectrometry (LC-MS). In order to address these issues, we implemented the use of LC-MS friendly conditions using a low-hydrophobicity cyano-propyl column (Agilent Zorbax SB-CN). We successfully differentiated between isomeric carotenoids by optimizing two gradient methods and using a mixture of 11 standards and LC-MS in positive ionization mode. Three complex biological samples from strawberry leaf, chicken feed supplement, and the photosynthetic bacterium Chloroflexus aurantiacus were analyzed and several carotenoids were resolved in these diverse backgrounds. Our results show this methodology is a significant improvement over other alternatives for analyzing carotenoids because of its ease of use, rapid analysis time, high selectivity, and, most importantly, its compatibility with typical LC-MS conditions.

Polymethacrylate-based monoliths as stationary phases for separation of biopolymers and immobilization of enzymes.

The experiences in the production and application of polymethacrylate-based monolithic supports, since their development almost thirty years ago, are presented. The main driving force for the development of new chromatographic supports was the necessity for the isolation and separation of physiologically active biopolymers and their use for therapeutic purposes. For this sake, a development of a method for fast separation, preventing denaturation and preserving their biological activity was necessary. Development of polysaccharide-based supports, followed by the introduction of polymer-based chromatographic media, is shortly described. This development was followed by the advances in monolithic media that are now used for both large- and small-scale separation of biopolymers and nanoparticles. Finally, a short overview is given about the applications of monoliths for sample displacement chromatography, resulting in isolation of physiologically active biomolecules, such as proteins, protein complexes, and nucleic acid, as well as high-throughput sample preparation for proteomic investigations.

A fast and efficient size separation method for haploid embryonic stem cells.

Hemizygous mutations introduced in haploid genomes can directly expose a phenotype, thus facilitating gene function analysis and forward genetic screening. Recently, mammalian haploid cells could be derived from mouse, rat, monkey, and human embryos and have been applied to screens of cellular mechanisms including cell signaling, pathogen host factors, and developmental pathways. Notably, haploid cell cultures have an intrinsic tendency for diploidization and, thus, require periodic cell sorting. Here, we report a method for rapid purification of haploid mouse embryonic stem cells from mixed cell populations with high viability and yield. Our method uses membranes with micrometer pores for force-free separation and facilitates enrichment of haploid cells without flow cytometry. The separation method simplifies maintaining haploid cell cultures and has further applications in establishing haploid cell lines from embryos and isolating cell cycle phases of mammalian cells.

Organic Acids Chemical Profiling in Food Items

A fast separation method for simultaneous determination of eleven organic acids was validated and applied to different commercial food items to evaluate their organic acids content. The present method gives detection limits between 0.04 and 4.65 mg mL-1, recovery values in real samples between 78.2 and 97.3% and relative standard deviation values for precision lower than 5%. All validation data were in acceptable range and prove the method�s fit for purpose. The advantages of the method are the short runtime analysis (15 min), no preparation step for the samples before the injection combined with good sensitivity which recommends it for routine control analysis in food industries. Moreover, this methodology has high potential in drinks industry but can by further extended to other types of food items.

Fabrication and characterization of CeO2-TiO2-Fe2O3 magnetic nanoparticles for rapid removal of uranium ions from industrial waste solutions

Uranium is considered one of the most dangerous heavy metals in the environment due to its chemical toxicity and radioactivity. As uranium contamination threatens both the surface and ground waters, it was important to devote more efforts toward new materials and technologies for separation of uranium from aqueous solutions. In this work, CeO2-TiO2-Fe2O3 was prepared as a novel magnetic nanosorbent for uranium ions removal from waste industrial solutions. The prepared nanohybrid oxide was fabricated by a facile low-temperature co-precipitation method. It was described utilizing Fourier Transform Infra-Red spectroscopy (FT-IR), X-ray diffraction (XRD), Raman, Brauner Emette Teller (BET) surface area, vibrating sample magnetometer (VSM) and Transmission Electron Microscopy (TEM). The adsorptions process was well fitted to the Freundlich and Hasely adsorption isotherm models. The sorption of uranium on CeO2-TiO2-Fe2O3 nanosorbent particles was pH dependent, and the maximum uranium adsorption capacity was found at pH6. The percentage of uranium removal approached equilibrium with sorption capacity (≥96) at 0.005g of nanoadsorbent. The present study suggested that magnetic CeO2-TiO2-Fe2O3 nanosorbent can be used as a potential adsorbent for sorption uranium and also provided a simple fast separation method for removal of heavy metal ions from aqueous solution.

Segmented targeted least squares estimator for material decomposition in multibin photon-counting detectors.

We present a fast, noise-efficient, and accurate estimator for material separation using photon-counting x-ray detectors (PCXDs) with multiple energy bin capability. The proposed targeted least squares estimator (TLSE) is an improvement of a previously described A-table method by incorporating dynamic weighting that allows the variance to be closer to the Cramér-Rao lower bound (CRLB) throughout the operating range. We explore Cartesian and average-energy segmentation of the basis material space for TLSE and show that, compared with Cartesian segmentation, the average-energy method requires fewer segments to achieve similar performance. We compare the average-energy TLSE to other proposed estimators-including the gold standard maximum likelihood estimator (MLE) and the A-table-in terms of variance, bias, and computational efficiency. The variance and bias were simulated in the range of 0 to 6cm of aluminum and 0 to 50cm of water with Monte Carlo methods. The Average-energy TLSE achieves an average variance within 2% of the CRLB and mean absolute error of [Formula: see text]. Using the same protocol, the MLE showed variance within 1.9% of the CRLB ratio and average absolute error of [Formula: see text] but was 50 times slower in our implementations. Compared with the A-table method, TLSE gives a more homogenously optimal variance-to-CRLB ratio in the operating region. We show that variance in basis material estimates for TLSE is lower than that of the A-table method by as much as [Formula: see text] in the peripheral region of operating range (thin or thick objects). The TLSE is a computationally efficient and fast method for material separation with PCXDs, with accuracy and precision comparable to the MLE.

On-site separation of Cr(vi) and Cr(iii) in natural waters by parallel cartridge ion-exchange columns

Development of a simple, fast, portable, and solvent-free method for on-site separation of Cr( = 6 \* ROMAN vi) and Cr( = 3 \* ROMAN iii) in natural waters.

Preparation of filter paper with chiral separation function by oxidation and Schiff-base reaction

Paper chromatography (PC) is a highly flexible, fast, and efficient separation method. In this study, a chromatographic paper with a chiral separation function was investigated and a paper chromatographic method for chiral separation was developed. Single-factor experiments and orthogonal tests were used to determine the optimal oxidation conditions for filter paper. The optimal conditions were that sodium periodate 4% (mass percentage), pH 2 buffer solution, reaction temperature 45℃, and reaction time 4 h. Under the optimal conditions, the aldehyde group content of a dialdehyde-based filter paper was 57.93% (amount of substance percentage). A paper-based chiral separation material was synthesized by a microwave-assisted Schiff-base reaction of the oxidized filter paper with L-glutamic acid. The developing solvent for separating racemic tartaric acid using this chiral filter paper consisted of 100 mL of n-butanol, 50 mL of 50%(v/v) acetic acid, and 0.1000 g of bromophenol blue. The rate of flow (Rf) values of L-tartaric acid and D-tartaric acid were 0.52 and 0.40, respectively. This method does not require large-scale equipment to perform the chiral separation and it is therefore suitable for general teaching, research, and industrial applications.

Development of a fast method for simultaneous determination of hippuric acid, mandelic acid, and creatinine in urine by capillary zone electrophoresis using polymer multilayer-coated capillary.

This paper reports the development of a fast separation method employing capillary zone electrophoresis for the simultaneous determination of hippuric acid, mandelic acid, and creatinine in samples of urine using a coated capillary. The background electrolyte was composed of 10mmolL-1 tris(hydroxymethyl)aminomethane and 30mmolL-1 2-hydroxy-isobutyric acid at pH3.6. The internal standard was 3,5-dihydroxybenzoic acid. Separations were performed in a fused silica capillary (32cm total length, 8.5cm effective length, and 50μm internal diameter) coated with crosslinked hydroxypropyltrimethyl ammonium chloride chitosan and κ-carrageenan. Direct UV detection was performed at a wavelength of 200nm. Samples and standards were injected hydrodynamically (-50mbar, 3s) using the short-end injection procedure. The electrophoretic system was operated under constant voltage of 30kV with positive polarity on the injection side. The separation time for hippuric acid, mandelic acid, and creatinine was less than 70s. The evaluation of some analytical parameters of the method for the three analytes showed good linearity (R 2 > 0.99), limit of detections of 0.21 to 0.63mgL-1, inter-day precision better than 3.0% (peak area), and recovery in the range of 98 to 106%. The method developed was applied in the analysis of the three analytes in urine samples. Graphical Abstract New method using capillary zone electrophoresis for analysis of creatinine, hippuric acid and mandelic acid in urine.