Purification Conditions Research Articles

Determination of 31 pesticide residues in wolfberry by LC-MS/MS and dietary risk assessment of wolfberry consumption

A modified QuEChERS method coupled with LC-MS/MS was developed and validated to detect 31 pesticides in wolfberry. The conditions for extraction solvent and QuEChERS purification were optimized. The validated method was applied to analyse pesticides in 200 wolfberry samples. The risk from chronic and acute dietary intake of the detected pesticide residues was assessed by the acceptable daily intake (ADI) and acute reference dose (ARfD), respectively, and the cumulative intake risk posed by the detected residues was assessed by the hazard index (HI). The results showed that 23 pesticides were detected in all wolfberry samples. The risk from chronic dietary intake was between 0.0001% and 1.6067%, and the risk from acute dietary intake was between 0.0010% and 0.4999%, which were all far below 100%. The HI was 0.02569 for chronic dietary intake and 0.015164 for acute dietary intake, which were both far below 1. The results indicated that the pesticide residues in wolfberry would not cause potential risk to human health. This work not only enhances our understanding of the potential exposure risks of pesticide residues in wolfberry, but also provides an effective method for the risk assessment of pesticide residues in other agricultural products.

Evaluation of the Collateral Activity Of CRISPR/Cas13a-Ribonuclease on the Agilent 2100 Bioanalyzer

The paper describes an original technique for detecting the collateral activity of CRISPR/Cas 13a ribonuclease based on the assessment of ribosomal RNA degradation. The Agilent 2100 bioanalyzer is used as an analyzing device. This approach is an alternative to existing detection methods and has a number of advantages over them in the case when a quantitative assessment of activity is not required. On the example of the test sample, the optimal concentrations and ratios of the components of the reaction mixture, which are necessary to obtain the most indicative result, were determined. The proposed technique can be used for qualitative assessment of the activity of recombinant ribonuclease Cas13a preparations obtained under different conditions of heterologous protein expression and purification, as well as for testing guide RNAs.

Утилизация растворов электрорафинирования меди переработки лома цветных металлов

The results of studies on the utilization of copper electrorefining solutions, zinc-containing sublimation dusts of pyrometallurgical processing of non-ferrous metal scrap are presented. Zinc-containing sublimation dusts for the regeneration of commercial electrolyte by the neutralization method were used for the first time. Contained in dust, zinc oxide, when dissolved in a sulfuric acid electrolyte, binds sulfate ions of free sulfuric acid and increases the pH of the solution. When the pH of the precipitation of non-ferrous metals is reached, they are precipitated in the form of hydroxides, which makes it possible to return to processing a significant amount of copper, nickel, zinc, lead and tin contained in them. Studies of the material composition of the commercial electrolyte of copper and zinc sublimates for the processing of non-ferrous metal scrap have been carried out. The conditions for purification of the electrolyte by the method of staged neutralization are determined. The first stage of neutralization was carried out with zinc sublimates, the second and third stages with potash. As a result of the first stage of neutralization to pH 4.7, lead was obtained - a tin-containing product that can be processed together with lead-containing copper electrorefining sludge. As a result of the second stage of neutralization with potash to pH 7.1, a precipitate was obtained, after treatment of which in a KOH solution, a precipitate of copper oxide was obtained. As a result of the third stage of neutralization to pH 9.5, a nickel-zinc-containing precipitate was obtained. After treating the precipitate with a KOH solution, a zinc-containing solution and a nickel-containing precipitate were obtained, after calcining which a nickel oxide precipitate was obtained.

Bioactivity guided isolation and identification of phenolic compounds from Citrus aurantium L. with anti-colorectal cancer cells activity by UHPLC-Q-TOF/MS

Natural plants are rich sources of various bioactive compounds. Consequently, the efficiently isolation of these bioactive components has always attracted considerable attention. Our work aims to demonstrate a framework for bioactivity guided isolation of potential effective compounds from the complex food materials. We demonstrated its application for isolation of phenolic compounds with anti-proliferative activity against colorectal cancer cells (CRCs) from Citrus aurantium L. Firstly, phenolic rich fraction was successfully identified as the main effective components that could simultaneously suppress the growth of CRCs and inhibit Wnt signaling. In order to obtain the bioactive phenolic constituents, a detailed study was performed by optimizing the purification conditions. Two phenolic rich fractions (40% and 60% ethanol elution fractions) were then obtained by AB-8 macroporous resins under optimized condition. Finally, the main components (65 compounds) were tentatively identified from the 40% ethanol eluant by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) analysis. Notably, there were five of the phytochemicals (Feruloylagmatine, Haploside C, Sagittatin A, Linderagalactone C and Koparin-2′-methyl ether) which were hitherto unidentified in Citrus aurantium L. fruit. In conclusion, this study showed that under the principle of bioactivity guided strategy, phenolic constituents with potential anti-CRCs activity were isolated from Citrus aurantium L.

Purification of polysaccharide from Solanum nigrum L. by S-8 macroporous resin adsorption

To study the purification conditions of polysaccharide from Solanum nigrum L. by S-8 macroporous adsorption resin. The effect of multi-factors on the purification of polysaccharide from Solanum nigrum were studied by static - dynamic adsorption and desorption methods with indexes of adsorption and desorption rates. The optimized purification process condition was as follows: the concentration of sample was 5 mg/mL, pH level was 7.0, temperature was 30 °C, the adsorption velocity was 0.5 mL/min, the maximun loading amount was 10 BV, 0.5 mol/L NaCl solution 5BV was used as eluent, elution flow rate was 4 mL/min. With this condition, the purity of Solanum nigrum polysaccharide was 91.00%, which was 1.989 times higher than before. S-8 macroporous resin can be used to separate and purify the solanum nigrum polysaccharide and improve the purity and quality of polysaccharides.

Lab Scale Extracted Conditions of Polyphenols from Thinned Peach Fruit Have Antioxidant, Hypoglycemic, and Hypolipidemic Properties.

Thinned peach polyphenols (TPPs) were extracted by ultrasonic disruption and purified using macroporous resin. Optimized extraction conditions resulted in a TPPs yield of 1.59 ± 0.02 mg GAE/g FW, and optimized purification conditions resulted in a purity of 43.86% with NKA-9 resin. TPPs composition was analyzed by UPLC-ESI-QTOF-MS/MS; chlorogenic acid, catechin, and neochlorogenic acid were the most abundant compounds in thinned peaches. Purified TPPs exhibited scavenging activity on DPPH, ABTS, hydroxyl radical, and FRAP. TPPs inhibited α-amylase and α-glucosidase by competitive and noncompetitive reversible inhibition, respectively. TPPs also exhibited a higher binding capacity for bile acids than cholestyramine. In summary, TPPs from thinned peaches are potentially valuable because of their high antioxidant, hypoglycemic, and hypolipidemic capacities, and present a new incentive for the comprehensive utilization of thinned peach fruit.

A rapid one-step process for the isolation of antibacterial peptides by silica-decorated Fe3O4nanoparticles

Antimicrobial peptides (AMPs), which are widely used as food preservatives, were purified to control the spoilage microorganism Alicyclobacillus acidoterrestris. The AMPs were produced by Pediococcus acidilactici CICC10344 and purified by silica-decorated Fe3O4 nanoparticles (SMNPs). The SMNPs were synthesized and characterized by transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). The diameter of the SMNPs was 31 ± 7 nm. The VSM measurements indicated that the saturation magnetization value (Ms) of the SMNPs was 30 emu/g. We monitored AMP binding to the surface of Fe3O4 nanoparticles by FT-IR, showing that the amide had been successfully formed. The optimal condition for purification by SMNPs was an AMP concentration of 0.5 mg/mL for 30 min of exposure. The AMP purified by SMNPs retained good antimicrobial activity in pH 4–8 and temperature of 80 °C and 100 °C for 20 min. Scanning electron microscope (SEM) images indicated that a likely antibacterial mechanism is pore formation in the cell membrane. The one-step process proposed in the present work is convenient and effective for the purification of antibacterial peptides that may be widely used for the purification of other peptides.

A Convenient Synthesis of Polysubstituted Coumarin‐pyrrolo[2,1‐a]isoquinoline‐1‐carbaldehydes from Isoquinoline, 2‐Bromoacetophenones and Coumarin‐β‐chlorovinyl Aldehydes

AbstractIn this research, a simple and efficient strategy for the straightforward synthesis of polysubstituted coumarin‐pyrrolo[2,1‐a]isoquinoline‐1‐carbaldehydes is presented by a sequential three‐component reaction of isoquinoline, 2‐bromoacetophenones and 3‐chloro‐3‐(2‐oxo‐2H‐chromen‐3‐yl)acrylaldehydes as readily available starting materials, which includes base‐mediated 1,4‐addition or [3+2] cycloaddition/intramolecular cyclization/formation two C−C bonds/aromatization tandem reaction under air. In this method, chemoselective cascade process, easily accessible starting materials, energy conserving (short reaction times at room temperature), simplicity of product purification (the products can be purified by washing with EtOH), excellent yields (75–88 %), metal‐free catalyst, green and mild conditions in one‐pot are important highlighted advantages of this protocol.

Isolation, structural modification, characterization, and bioactivity of polysaccharides from Folium Isatidis

The purification process of Folium Isatidis polysaccharide (FIP) was optimized by response surface method (RSM) using AB-8 macroporous resin. A major homogeneous polysaccharide, named FIP-Ⅱ, was purified from FIP through DEAE-650 M and Sephadex G-75 column chromatography. The structure of the FIP-Ⅱ was investigated through the combination of HPLC, GC, FT-IR, sequential acid hydrolysis, peroxide oxidation, Smith degradation, and NMR analysis. Then, the sulfated, phosphorylated, and carboxymethylated derivatives of FIP-Ⅱ, namely FIP-Ⅱ-S, FIP-Ⅱ-P, and FIP-Ⅱ-C, were prepared. Their structures were characterized by extensive analysis of chromatographic and spectroscopic methods including UV, HPLC, GC, FT-IR, Congo red, CD, SEM-EDX, XRD, TG, DTG, and DSC. Results of RSM showed that optimum purification conditions were elution flow rate 2.76 BV/ h, the sample concentration 2.03 mg/mL, and the elution volume was 1.26 BV. The average comprehensive score of purification was up to 76.28%. FIP-Ⅱ and its derivatives were heteropolysaccharides composed of different molar ratios of rhamnose, arabinose, xylose, mannose, glucose, and galactose, with a molecular weight of 775.64, 911.75, 1288.31, and 1013.61 kDa. The structure modification influences the solution conformation, surface morphology, crystalline nature, and thermal properties of the FIP-Ⅱ and its derivatives. Antioxidant activity tests showed that structure modification could significantly enhance the activity of the polysaccharides differently. It could be a potential ingredient in the functional food and pharmaceutical industry.

Optimal Conditions for Extraction and Purification of Penicillinase Enzyme

Optimal Conditions for Extraction and Purification of Penicillinase Enzyme

Recombinant Transcription Factors (TFs) Fused to ZEBRA Minimal Transduction Domain (MD) for Modulation of mRNA Transcripts.

Transcription factors (TFs) are key players in the control of gene expression and consequently all major cellular process, ranging from cell fate determination to cell cycle control and response to the environment.In particular cases, their ectopic expression has shown great promise in cell reprogramming for regenerative medicine, ontogenesis studies, and cell modeling. The current reprogramming methods mainly rely on gene transfer, therefore require technological improvements to limit genetic imprinting and improve safety. Direct protein delivery could represent an attractive alternative. Cell-penetrating peptides (CPPs) fused to recombinant TFs or other proteins involved in the epigenetic definition of cells have great potential in this context. We have thus developed the direct vectorization of Oct4, Sox2, or Nanog TFs and the posttranscriptional regulatory RNA-binding protein Lin28a by using the minimal transduction domain (MD11) of Epstein-Barr virus ZEBRA protein.This section describes the molecular cloning and production of different TFs fused to ZEBRA MD11 domain in the E. coli expression system. We also include the optimized purification conditions for each recombinant protein. The treatment of primary fibroblasts as well as cord blood-derived hematopoietic stem cells is also described. Finally, the transcriptional activation of the target genes following the transfer of TFs analyzed by quantitative PCR is presented.Our work primarily finds applications for advanced medicinal products, an area that requires novel therapy designs and delivery systems devoid of genetic material transfer to improve safety.

Enhancement on antioxidant and antibacterial activities of Brightwell blueberry by extraction and purification

A blueberry anthocyanin extract was obtained from Brightwell blueberry fruits cultivated in eastern China and the extraction and purification conditions were optimized. The components of the anthocyanin extract were identified using ultra-performance liquid chromatography-electrospray ionization interface-mass spectrometer. The antioxidant and antibacterial activities of the blueberry fruit supernatant (BFS), blueberry anthocyanin crude extract (BCE), and blueberry anthocyanin rich extract (BRE) were evaluated. The extraction yield was 1.79 ± 0.0014 mg/g under the following optimal conditions: 1:20 solid-to-liquid ratio (v/w), 24 h, 34 °C, and 90% ethanol containing 0.21% (v/v) hydrochloric acid. With regard to purification, anthocyanin purity increased 19.1-fold. Nine fractions were identified as the glycosides of delphinidin, cyanidin, petunidin, and malvidin. The biological activities of the blueberry anthocyanin extract were improved through extraction and purification. Compared with BFS and BCE, BRE had a higher DPPH radical scavenging activity (EC50 = 0.51 mg/mL), ABTS antioxidant capacity (EC50 = 0.32 mg/mL), and oxygen radical absorbance capacity (0.43 mmol Trolox/g). Furthermore, BRE (2 mg/mL) showed a maximum of 84.64 ± 0.35% reduction in the biofilm biomass of Listeria monocytogenes and the inhibition zone given by BRE against Escherichia coli was 16.04 ± 0.38 mm. BRE showed the highest antioxidant capacities and obvious antibacterial effects against food-related microorganisms than the other samples. Therefore, BRE can be used as a natural antioxidant and antibacterial agent and has potential health advantages and food industry applications.

Manganese removal from zinc sulfate electrolyte by electro-oxidation using Pb-Ag anode

ABSTRACT The optimum conditions for manganese dioxide (MnO2) removal were investigated in two simulated conditions, purification and electrowinning, using a Pb-0.7 wt.% Ag electrode. Linear sweep voltammetry and Cyclic voltammetry tests were conducted to study the effect of temperature and concentrations. SEM-EDS and XRD were employed to study the surface characterisations and chemical compositions. The results revealed that the electrowinning operating conditions are more appropriate than the purification conditions for MnO2 removal. The highest current efficiency of manganese removal was 21% which was obtained in the EW electrolyte at 125 A m−2 at 40°C after 2 h of electrolysis. The Current Efficiency was increased significantly at lower Mn ion concentrations (0.1–1.0 g L−1) while it stayed constant beyond the concentration of 1.0 g L−1. The results showed that an increase in temperature depolarised the oxygen evolution reaction and the addition of Mn2+ suppressed formation of PbO2 on anode surface.

Evaluating the efficacy of immobilized metal affinity chromatography (IMAC) for host cell protein (HCP) removal from anti-HER2 scFv expressed in Escherichia coli

Host cell proteins (HCPs) are process-related impurities that have influence on product safety and efficacy. HCPs should effectively be removed by chromatographic steps in downstream purification process. In this study, we aimed to evaluate the efficacy of immobilized-metal affinity chromatography (IMAC) for separation of HCPs from anti-HER2 single chain fragment variable (scFv) expressed in E. coli. This study explored how different purification conditions including native, denaturing and hybrid affect HCP level in purified anti-HER2 scFv. Furthermore, the effects of NaCl concentration in wash buffer as well as imidazole concentration in wash and elution buffer on purification yield and HCP level in purified anti-HER2 scFv were evaluated.It was found that increasing imidazole concentration in wash and elution buffers in native conditions reduced the yield of anti-HER2 scFv purification. However, enhancing NaCl concentration in wash buffer in purification under native conditions led to significant increase in the amount of anti-HER2 scFv without any change in protein purity. Herein, none of the IMAC purification methods conducted on soluble cytoplasmic proteins under native conditions could reduce the amount of HCP to acceptable level. HCP content was only lowered to ˂ 10 ppm when inclusion bodies were purified under hybrid conditions. Furthermore, increasing imidazole concentration in wash buffer in purification under hybrid conditions led to significant increase in eluted anti-HER2 scFv concentration, while HCP content was also increased in this condition. Overall, purification under hybrid conditions using wash buffer containing 40 mM imidazole resulted in the highest yield and acceptable level of HCP.

Optimization of Extraction or Purification Process of Multiple Components from Natural Products: Entropy Weight Method Combined with Plackett-Burman Design and Central Composite Design.

In this paper, the optimization of the extraction/purification process of multiple components was performed by the entropy weight method (EWM) combined with Plackett–Burman design (PBD) and central composite design (CCD). We took the macroporous resin purification of Astragalus saponins as an example to discuss the practicability of this method. Firstly, the weight of each component was given by EWM and the sum of the product between the componential content and its weight was defined as the comprehensive score, which was taken as the evaluation index. Then, the single factor method was adopted for determining the value range of each factor. PBD was applied for screening the significant factors. Important variables were further optimized by CCD to determine the optimal process parameters. After the combination of EWM, PBD and CCD, the resulting optimal purification conditions were as follows: pH value of 6.0, the extraction solvent concentration of 0.15 g/mL, and the ethanol volume fraction of 75%. Under the optimal conditions, the practical comprehensive score of recoveries of saponins was close to the predicted value (n = 3). Therefore, the present study provided a convenient and efficient method for extraction and purification optimization technology of multiple components from natural products.

Purification of Ethyl Linoleate from Foxtail Millet (Setaria italica) Bran Oil via Urea Complexation and Molecular Distillation.

Foxtail millet (Setaria italica) bran oil is rich in linoleic acid, which accounts for more than 60% of its lipids. Ethyl linoleate (ELA) is a commercially valuable compound with many positive health effects. Here, we optimized two ELA processing steps, urea complexation (UC) and molecular distillation (MD), using single-factor and response surface analyses. We aimed to obtain a highly concentrated ELA at levels that are permitted by current regulations. We identified the optimal conditions as follows: 95% ethanol-to-urea ratio = 15:1 (w/w), urea-to-fatty acid ratio = 2.5:1 (w/w), crystallization time = 15 h, and crystallization temperature = −6 °C. Under these optimal UC conditions, ELA concentration reached 45.06%. The optimal MD purification conditions were established as follows: distillation temperature = 145 °C and vacuum pressure = 1.0–5.0 × 10−2 mbar. Under these conditions, ELA purity increased to 60.45%. Together, UC and MD were effective in improving the total concentration of ELA in the final product. This work shows the best conditions for separating and purifying ELA from foxtail millet bran oil by UC and MD.

Highly efficient recovery and purification of scandium from the waste sulfuric acid solution from titanium dioxide production by solvent extraction

The waste sulfuric acid solution generated from titanium dioxide production is called titanium dioxide waste acid (TWWA), which is an important resource for scandium production. A way including enrichment and purification stages for recovery and purification of Sc from TWWA with 10% P204 - 5% TBP synergistic extraction system was studied. In the enrichment stage, the preferred experimental conditions were obtained, i.e., the A/O ratio: 30, 25 °C, contact time: 30 min. In the following purification stage, the above-obtained enrichment products by stripping with 5 M NaOH were dissolved with 3 M HCl with 1% H2O2 added. The added H2O2 can lead to Ti form peroxy complex ([TiO(H2O2)]2+) that can effectively inhibit its co-extraction into the oil phase. The optimized purification conditions were the A/O ratio of 5, 30 min and 11 mmol/L Sc concentration. The stripping products obtained from the purification stage were dissolved with 2 M HCl, and then 0.5 M H2C2O4 was added to precipitate scandium. After washing and calcining, a product of 99.28% Sc2O3 was obtained. The recovery rate of scandium in the whole process was 90.34%.

Fully Automated Screening of a Combinatorial Library to Avoid False Positives: Application to Tetanus Toxoid Ligand Identification.

Peptide ligands are widely used in protein purification by affinity chromatography. Here, we applied a fully automated two-stage library screening method that avoids false positive peptidyl-bead selection and applied it to tetanus toxoid purification. The first library screening was performed using only sulforhodamine (a fluorescent dye), and fluorescent beads were isolated automatically by flow cytometry and discarded. A second screening was then performed with the rest of the library, using the target protein (tetanus toxoid)–rhodamine conjugate. This time, fluorescent beads were isolated, and peptide sequences were identified by matrix-assisted laser desorption/ionization tandem mass spectrometry. Those appearing with greater frequency were synthesized and immobilized on agarose to evaluate a range of chromatographic purification conditions. The affinity matrix PTx1-agarose (Ac-Leu-Arg-Val-Tyr-His-Gly-Gly-Ala-Gly-Lys-agarose) showed the best performance when 20 mM sodium phosphate, 0.05% Tween 20, pH 5.9 as adsorption buffer and 100 mM Tris-HCl, 100 mM NaCl, pH 8.0 as elution buffer were used. A pure tetanus toxoid (Ttx) was loaded on a chromatographic column filled with the PTx1 matrix, and 96% adsorption was achieved, with a Kd of 9.18 ± 0.07 nmol/L and a qm of 1.31 ± 0.029 μmol Ttx/mL matrix. Next, a Clostridium tetani culture supernatant treated with formaldehyde (to obtain the toxoid) was applied as a sample. The sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis showed a band, identified by electrospray ionization mass spectrometry as the Ttx, that appeared only in the elution fraction, where an S-layer protein was also detected.

Adsorption and Desorption Characteristics of Total Flavonoids from Acanthopanax senticosus on Macroporous Adsorption Resins.

We examined the application of six different resins with the aim of selecting a macroporous resin suitable for purifying Acanthopanax senticosus total flavonoids (ASTFs) from Acanthopanax senticosus crude extract (EAS) by comparing their adsorption/desorption capacities, which led to the selection of HPD-600. Research on the adsorption mechanism showed that the adsorption process had pseudo-second-order kinetics and fit the Freundlich adsorption model. Moreover, the analysis of thermodynamic parameters indicated that the adsorption process is spontaneous and endothermic. The optimal conditions for purification of ASTFs were determined as sample pH of 3, 60% ethanol concentration, and 3 BV·h−1 flow rate, for both adsorption and desorption, using volumes of 2.5 and 4 BV, respectively. The application of macroporous resin HPD-600 to enrich ASTFs resulted in an increase in the purity of total flavonoids, from 28.79% to 50.57%. Additionally, the antioxidant capacity of ASTFs was higher than that of EAS, but both were lower than that of L-ascorbic acid. The changes in ASTFs compositions were determined using ultra-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS), with the results illustrating that the levels of seven major flavonoids of ASTFs were increased compared to that in the crude extract.

Lyapunov Exponents for Quantum Channels: An Entropy Formula and Generic Properties

We denote by Mk the set of k by k matrices with complex entries. We consider quantum channels φL of the form: given a measurable function L: Mk → Mk and a measure µ on Mk we define the linear operator φL : Mk → Mk , by the law ρ → φL (ρ) = ∫ Mk L(v)ρL(v)† dµ(v). In a previous work, the authors show that for a fixed measure µ the Φ-Erg property is generic on the function L (also irreducibility). Here we will show that the purification property is also generic on L for a fixed µ. Given L and µ there are two related stochastic processes: one takes values on the projective space P (ℂ k ) and the other on matrices in Mk . The Φ-Erg property and the purification condition are the nice hypothesis for the discrete time evolution given by the natural transition probability. In this way it will follow that generically on L, if ∫ |L(v)|2 log |L(v)| dµ(v) < ∞, the Lyapunov exponents ∞ > γ 1 ≥ γ 2 ≥ … ≥ γk ≥ −∞ are well defined. In a previous work, the concepts of entropy of a channel and Gibbs channel were presented; and also an example (associated to a stationary Markov chain) in which this definition of entropy (for a quantum channel) matches the Kolmogorov-Shanon definition of entropy. We estimate here the larger Lyapunov exponent for the mentioned example and we show that it is equal to −1/2 h, where h is the entropy of the associated Markov invariant probability.