Solvent Precipitation Research Articles

Recovery of 400 Chemicals with Three Extraction Methods for Low Volumes of Human Plasma Quantified by Instrumental Analysis and In Vitro Bioassays.

Human biomonitoring studies are important for understanding adverse health outcomes caused by exposure to chemicals. Complex mixtures of chemicals detected in blood - the blood exposome - may serve as proxies for systemic exposure. Ideally, several analytical methods are combined with in vitro bioassays to capture chemical mixtures as diverse as possible. How many and which (bio)analyses can be performed is limited by the sample volume and compatibility of extraction and (bio)analytical methods. We compared the extraction efficacy of three extraction methods using pooled human plasma spiked with >400 organic chemicals. Passive equilibrium sampling (PES) with polydimethylsiloxane (PDMS) followed by solid phase extraction (PES + SPE), SPE alone (SPE), and solvent precipitation (SolvPrec) were compared for chemical recovery in LC-HRMS and GC-HRMS as well as effect recovery in four mammalian cell lines (AhR-CALUX, SH-SY5Y, AREc32, PPARγ-BLA). The mean chemical recoveries were 38% for PES + SPE, 27% for SPE, and 61% for SolvPrec. PES + SPE enhanced the mean chemical recovery compared to SPE, especially for neutral hydrophobic chemicals. PES + SPE and SolvPrec had effect recoveries of 100-200% in all four cell lines, outperforming SPE, which had 30-100% effect recovery. Although SolvPrec has the best chemical recoveries, it does not remove matrix like inorganics or lipids, which might pose problems for some (bio)analytical methods. PES + SPE is the most promising method for sample preparation in human biomonitoring as it combines good recoveries with cleanup, enrichment, and potential for high throughput.

Research on low temperature properties and physical hardening effect of asphalt components

It is generally recognized in current research that asphalt binder is composed of four components, i.e., saturates, aromatics, resins and asphaltenes, and the physicochemical properties of asphalt binder are closely related to the properties of the components. In this paper, solvent precipitation and chromatographic column method were used to extract and separate a sufficient amount of four components, and different components were recombinant according to the original ratio to form components recombinant materials. Using Fourier Transform Infrared, dynamic shear rheometer and differential scanning calorimetry to characterize the chemical composition and low temperature rheological properties of single component and components recombinant materials, including amplitude sweeping, temperature sweeping, time sweeping temperature-frequency sweeping and relaxation test. The response of the material to the physical hardening effect at low-temperature isothermal storage was also explored. The test results show that, within the test temperature range, the aromatics does not produce physical hardening effect, while the saturates and resins produced a certain degree of physical hardening effect. The free volume, phase angle, and complex shear modulus have different response times to the physical hardening effect, so the free volume theory alone is not sufficient to explain the physical hardening effect. This paper proposes to use the method of area integral to evaluate the degree of response of materials to physical hardening, and to rank the materials.

Sub-micron spherical carbon particles with hollow cores from lignin-based hybrid precursors: preparation, characterization, and electrostatic dissipative application

Novel sub-micron, spherical, bio-based carbon materials with hollow-core characteristics were synthesized from spherical lignin particle (SLP) hybrid precursors via thermo-stabilization and carbonization. Primarily, the mixture of bagasse lignin (BG-L) and palm kernel shell lignin (PKS-L) with an addition of dicumyl peroxide (DCP) at different BG-L:PKS-L:DCP ratios was utilized to prepare SLPs through anti solvent precipitation. Interestingly, as-prepared SLPs having a 250–331 nm diameter contained hollow cores of 41–223 nm inside the spherical particles. A mechanism of hollow-core formation was also proposed. Effects of BG-L:PKS-L:DCP ratio, heating rate (HR), oxygen flow rate (O2 FR), and stabilization time (SBT) on spherical shape retention of SLPs after thermo-stabilization were systematically investigated, and a cross-link pathway was suggested. The spherical aspect of SLPs having hollow cores was successfully maintained at optimal conditions of 250 °C for 1 h with a HR of 0.3 °C/min under O2 FR of 3 L/min using a BG-L:PKS-L:DCP ratio of 1:1:1 by wt. After carbonization at 900–1200 °C, spherical carbon particles (SCPs) with hollow cores were obtained, possessing a high carbon (C) element of ≅ 93–96%, a high specific surface area of ≅ 308–593 m2/g, and a high order of graphitic structure (ID/IG ratio ≅ 1). The average particle size of SCPs and hollow-core dimensions were ≅ 171–224 and 80–107 nm, respectively. The polylactic acid (PLA)/SCP composite films were prepared using SCPs at different carbonization temperatures and loadings via a solution casting technique. The composite film containing 20 wt% of SCPs carbonized at 900 °C (SCPs-900) provided a surface resistance of ≅ 3 × 105 Ω and a tribo-charge voltage of 0 V, appropriate for electrostatic dissipative (ED) applications. The Young's modulus and elongation at break of the PLA/SCP-900 (20 wt%) composite film were ≅ 3.4 MPa and 2.0%, respectively. These findings demonstrate a feasible and effective approach to utilize biomass-based lignin for producing carbon particles with unique features as renewable and sustainable conductive fillers in polymer composites.

A Review of Opportunities and Methods for Recovery of Rhodium from Spent Nuclear Fuel during Reprocessing

Rhodium is one of the scarcest, most valuable, and useful platinum group metals, a strategically important material relied on heavily by automotive and electronics industries. The limited finite natural sources of Rh and exponentially increasing demands on these supplies mean that new sources are being sought to stabilise supplies and prices. Spent nuclear fuel (SNF) contains a significant quantity of Rh, though methods to recover this are purely conceptual at this point, due to the differing chemistry between SNF reprocessing and the methods used to recycle natural Rh. During SNF reprocessing, Rh partitions between aqueous nitric acid streams, where its speciation is complex, and insoluble fission product waste streams. Various techniques have been investigated for Rh recovery during SNF reprocessing for over 50 years, including solvent extraction, ion exchange, precipitation, and electrochemical methods, with tuneable approaches such as impregnated composites and ionic liquids receiving the most attention recently, assisted by more the comprehensive understanding of Rh speciation in nitric acid developed recently. The quantitative recovery of Rh within the SNF reprocessing ecosystem has remained elusive thus far, and as such, this review discusses the recent developments within the field, and strategies that could be applied to maximise the recovery of Rh from SNF.

Density-oriented deep eutectic solvent-based system for the selective separation of polysaccharides from Astragalus membranaceus var. Mongholicus under ultrasound-assisted conditions

The water extraction and ethanol precipitation method is an extraction method based on the solubility characteristics of polysaccharides that offers wide applicability in the extraction and separation of plant polysaccharides. However, this method leads to large amounts of proteins, nucleic acids, pigments, and other impurities in the polysaccharides products, which makes downstream purification complicated and time-consuming. In this study, a green, high-density natural deep eutectic solvents was used for the high-purity extraction and separation of polysaccharides from Astragalus membranaceus (Fisch) Bge. var. Mongholicus (Bge.) Hsiao roots under ultrasound-assisted conditions. In this study, 16 different natural deep eutectic solvents were designed to screen the best solvent for extracting Astragalus polysaccharides (APSs). Based on the yield and recovery of APSs, a natural deep eutectic solvents composed of choline chloride and oxalic acid with a molar ratio of 1:2 was selected. The related factors affecting polysaccharides extraction and solvent precipitation were investigated. To improve the operating methodology, single-factor trials, a Plackett-Burman design, and a Box-Behnken design were used. The optimal extraction process conditions were obtained as follows: water content of 55%, liquid–solid ratio of 24 mL/g, ultrasonic irradiation time of 54 min, ultrasonic irradiation temperature of 50 °C, ultrasonic irradiation power of 480 W, ethanol precipitation time of 24 h, and ethanol concentration of 75%. Under optimal extraction conditions, the recovery of APSs was 61.4 ± 0.6 mg/g. Considering the special matrix characteristics of A. membranaceus var. Mongholicus roots, physical-technology-based ultrasonic waves promote penetration, and the mass transfer function also solves the bottleneck of high-viscosity deep eutectic solvents in the extraction stage. In comparison with the conventional method, the proposed method based on deep eutectic solvents isolation can significantly increase APSs recovery, which is beneficial to simplifying the process of polysaccharides purification by using solvent properties to separate extracts and reduce impurities in APSs.

Precipitation solvents effect on the extraction of mucilaginous polysaccharides from Opuntia ficus-indica (Cactaceae): Structural, functional and rheological properties

This paper discusses mucilage extracted from Opuntia ficus-indica (Cactaceae) cladodes, also known as Barbary fig. Mucilaginous polysaccharides were extracted in hot water and purified with two distinct organic solvents, ethanol and isopropanol. The mucilaginous extract yield precipitated in isopropanol "MUIS″ (i.e. 23.2%) is higher than that of ethanol "MUET″ (i.e. 19%). The biochemical composition of mucilaginous extracts shows that the change in precipitation solvents has no significant effect. In addition, the microstructure of mucilaginous extracts exhibits amorphous and porous structures, which favor their capacity to retain moisture. The mucilaginous extracts analysis by ion chromatography reveals that after acid hydrolysis, MUIS has a higher total of sugars (46.9%) than MUET (37.6%). Mucilaginous extracts vary in their main content of monomers such as arabinose, galactose, glucose, and xylose as well as in the uronic acid fraction. The contact angle measurements were also established in order to investigate mucilaginous extracts’ hydrophilic or hydrophobic surfaces. Three tested liquids were used namely: distilled water, diiodomethane, and ethylene glycol. The X-ray diffraction analysis displayed that the precipitation solvent does not affect the amorphous structure. The TGA analyses of extracts under an oxidative atmosphere reveal that the oxygen flow accelerates the kinetics of degradation. Under nitrogen flow, mucilaginous extracts have intrinsic thermal resistance in specific temperature ranges. The DSC results show that the polysaccharide purification technique influences the glass temperature (Tg), which is around 53 °C and 61 °C for MUET and MUIS, respectively. In an aqueous solution, the mucilaginous extracts are highly heterogeneous, and the precipitation solvents and temperature affect their particle size. Mucilaginous extracts were concentration-dependent and reduced the surface tension of water to 43.5 mN/m and 30 mN/m for MUET and MUIS at 7 w/v%, respectively. The rheological analyses show that a non-Newtonian shear-thinning behavior was observed. The Ostwald-de Waele model successfully predicted the viscosity-shear rate relationship. The consistency coefficient (k) of MUIS at 7 w/v% (0.117 Pa.s) is higher than MUET at 7 w/v% (0.081 Pa.s). The critical concentrations (C*) of MUET and MUIS are 1.75% and 3.45 w/v%, respectively.

Validation of a method for itraconazole and major metabolite hydroxyitraconazole for LC-MS/MS analysis with application in a formulation clinical study

A high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for the analysis of itraconazole (ITZ) and hydroxyitraconazole (ITZ-OH) as part of a human pharmacokinetic study of novel tablet formulations. We demonstrated that 100 µL of plasma sample can be used with a protein precipitation extraction by optimizing different composition of acid in organic solvent for the precipitation solvent, giving comparable recovery to more time-consuming liquid-liquid or solid phase extractions. Additionally, we have shown that by monitoring the halogen isotopic peak for ITZ as well as optimizing chromatographic conditions, we are able to avoid carryover and endogenous interferences, allowing for a lower limit of quantification for our study. We validated the method to quantify ITZ and ITZ-OH from 1 to 250 ng/mL in human plasma and applied this to a formulation research clinical study (NCT04035187). This is the first itraconazole study to demonstrate robustness of the assay by performing interference testing of over-the-counter and common co-administered medications. We are also the first publication to perform incurred sample reanalysis (ISR) at the conclusion of a 672 sample clinical study to show reproducibility of assay performance.

Comparative mass transfer performance of CO2 absorption using highly-concentrated AMP-PZ-MEA ternary amines solvent

Mass transfer performance of CO2 absorption is based on selecting an effective amine solvent, hence, an examination of the overall mass transfer coefficient (KGav) and CO2 removal efficiency, is significant for obtaining the most favorable CO2 capture performance. This study compared KGav and CO2 removal efficiency of the highly concentrated ternary amines solvent at various concentrations with the benchmark monoethanolamine (MEA) in a laboratory scale CO2 absorption packed-column. The six blends of 2-amino-2-methyl-1-propanol (AMP), piperazine (PZ), and MEA are formulated as ternary solvents at high PZ/AMP molar ratio (1.25–3.75) and total amine concentration (6M and 7M). Be noted that the solvent precipitation was not observed in this study. The absorption experiment was operated at 303 K temperature, 12% CO2 by volume, and CO2 loading of 0.25 mol CO2/mol amine. The experimental results showed that KGav and CO2 removal efficiency for AMP-PZ-MEA and MEA solvents increased as total amine concentration increased. Also, KGav and CO2 removal efficiency of the PZ-AMP-MEA solvent are greater than those of 5M MEA. An increase of PZ/AMP molar ratio had a positive influence on the absorption performance for ternary amines. In comparison with the benchmark 5M MEA, all the studied AMP-PZ-MEA solvents showed an outperformance. The two suggested formulae, which are 0.95:3.55:1.5 (6M) and 0.95:3.55:2.5 (7M), possessed approximately 1.5 and 2.5 times higher KGav and 17.34% and 17.63% greater CO2 removal efficiency compared with the benchmark 5M MEA.

In Vitro Evaluation of the Antibacterial Activity of the Peptide Fractions Extracted from the Hemolymph of Hermetia illucens (Diptera: Stratiomyidae)

Antimicrobial peptides (AMPs) are a chemically and structurally heterogeneous family of molecules produced by a large variety of living organisms, whose expression is predominant in the sites most exposed to microbial invasion. One of the richest natural sources of AMPs is insects which, over the course of their very long evolutionary history, have adapted to numerous and different habitats by developing a powerful innate immune system that has allowed them to survive but also to assert themselves in the new environment. Recently, due to the increase in antibiotic-resistant bacterial strains, interest in AMPs has risen. In this work, we detected AMPs in the hemolymph of Hermetia illucens (Diptera, Stratiomyidae) larvae, following infection with Escherichia coli (Gram negative) or Micrococcus flavus (Gram positive) and from uninfected larvae. Peptide component, isolated via organic solvent precipitation, was analyzed by microbiological techniques. Subsequent mass spectrometry analysis allowed us to specifically identify peptides expressed in basal condition and peptides differentially expressed after bacterial challenge. We identified 33 AMPs in all the analyzed samples, of which 13 are specifically stimulated by Gram negative and/or Gram positive bacterial challenge. AMPs mostly expressed after bacterial challenge could be responsible for a more specific activity.

88 Microplastic References for Inhalation Studies

Abstract Microplastic research has been increasing due to the uncertainty of potential effects on the environment and human health. However, microplastic references are currently missing. Not only is there a lack of references there is also a lack of diversity in polymer type for references, especially in toxicological studies. In specific, inhalation studies must rely on microplastics that are respirable and/or inhalable (< 10 µm) to result in toxicological outcomes. Therefore, in this project, we focus on using solvent precipitation to produce microplastic references from TPU, PA-6, PET, and LDPE for microplastic inhalation toxicity studies. Particle size distribution of the dispersion is used to verify that the desired size range is achieved. To demonstrate that the produced microplastic references are representative from its original material, molecular and particle descriptors are characterized. Chemical composition, molecular weight, crystallinity, solidity, density, are among the descriptors tested for both the produced microplastic references and its corresponding commercial counterpart. Preliminary results have shown that quantities needed for in-vitro testing and particle size range desired is achieved with successful production of sub-100 nm constituent particle counts and all-respirable mass-based diameters. SEM images confirm the size distribution and show distribution of particle shapes. Chemical composition via spontaneous Raman Scattering illustrates clear polymer spectra signals from the microplastic dispersions. These microplastic reference materials are complemented by toxicology controls. In addition, the in-vitro screening uses both submersed and air-liquid interface cultures to expose cells. This study will thus provide information on microplastic material descriptors relevant for inhalation toxicity.

Simplified regular solution model for asphaltenes precipitation in crude oil blends

The regular solution model is used with Hankinson-Brobst-Thomson (HBT) molar volume correlation for saturates, aromatics, resins and asphaltenes (SARA) fractions for pure crude oils and blends to predict the precipitation of asphaltenes. The parameters of the HBT correlation were tuned with experimental data for SARA fractions densities. At the same temperature and pressure conditions, the precipitation of asphaltenes is greatly influenced by the presence of other compounds. SARA fractions were obtained according with ASTM D2007 using n-heptane as precipitant solvent. The use of average properties for saturates, aromatics and resins and the assumptions made in the model could reproduce precipitation curves for all study cases. Calculations of asphaltene precipitation prediction for pure oils showed an average absolute deviation between 0.12 and 0.69% for oil of Gulf of Mexico and Cold Lake oil, respectively. For blends it showed values between 0.08 and 0.65% for Cold Lake/Lloydminster-Asphaltene free blend and Cold Lake/Lloydminster-Gulf of Mexico blend respectively. The proposed model maintains its simplicity and can predict the asphaltene precipitation accurately.

Ion suppression, reduced long-term robustness and leakage current of the spray voltage during the ionization of trichloroacetic acid; a case study with a methylmalonic acid assay

Sample clean-up with the protein precipitation solvent trichloroacetic acid (TCA), combined with a stable isotope labeled internal standard, is widely used for the analysis of endogenous and exogenous compounds in serum and plasma with liquid chromatography-tandem mass spectrometry (LC–MS/MS). During the application of an assay for methylmalonic acid (MMA), used for routine analysis in patient care, negative long-term side effects of TCA on assay performance were observed. Step-by-step extensive troubleshooting disclosed the limitations of using TCA in MS. After running over 2000 samples with the MMA assay over a course of one year, a black coating formed between the probe and the heater that was traced to the use of TCA. The MMA assay used a C18 column with an isocratic eluent of 95% water (0.1% formic acid) as starting condition, on which TCA was more retained than MMA. Next, concentrations of 2.2% TCA in the prepared serum or plasma sample caused a drop in spray voltage during ionization into the MS. This was caused by the strong acid properties of TCA, resulting in current loss of the spray voltage between the heated electrospray ionization (HESI) needle and the union holder, which had also a grounding function. Replacing the original metal HESI needle with a custom made fussed silica HESI needle or detaching the union from the union holder, eliminated the effect of the drop in spray voltage. In conclusion, TCA can seriously affect the long-term robustness by affecting the source of the MS. We recommend the use of a very low sample injection volume, and/or shifting the mobile phase to waste when TCA is eluting, when using TCA in LC-MS/MS analysis.

Multiscale structure and precipitation mechanism of debranched starch precipitated by different alcohols

Alcohol solution is a cheap, simple, and effective precipitating solvent frequently used for separating debranched starch (DBS), yet little is known about the precipitation mechanism of DBS by different alcohols. This study precipitated DBS from pullulanase-hydrolyzed starch using ethanol, n-butanol, and isopentanol. The multiscale structures of DBS were characterized, including chain length, single/double helix, and crystalline. The chain conformation and precipitation mechanism of DBS in different alcohols was investigated using molecular dynamics (MD) simulation. DBS precipitated by n-butanol contained the largest proportion of short chain (DP6–24, 83.2 %), the highest V-type crystallinity (21.1 %), and the largest single-helix content (24.7 %). A single helix conformation of DBS chain was determined in alcohols, where alcohol molecules entered the helix cavity. Intra/inter-molecular hydrogen bonds stabilized the helix, with a large number of hydrogen bonds leading to strong molecular interaction and stable helical structure. The solvent accessible surface area of DBS chain decreased by 7.88–19.32 % in alcohols, and the radial distribution function revealed that the first solvent layer of DBS chain at 0.29 nm was closely related to hydrogen bonding. This study provides a basis for the choice of precipitation solvent for preparing DBS with different chain lengths and physicochemical properties.

Why proanthocyanidins elute at increasing order of molecular masses when analysed by normal phase high performance liquid chromatography? Considerations of use

Although it is widely known that proanthocyanidins elute at an increasing order of molecular masses when analysed by normal phase high performance liquid chromatography (NP-HPLC), there is no a consistent explanation of the mechanisms of their separation until now. Therefore, the aim of the present study was to give a reliable response to this question, using a complex procyanidin-rich grape seed extract. For this, an off-column static simulation of extract injection and a fragmented-column dynamic procyanidin location tests were studied to show their precipitation in an aprotic solvent, besides another off-column static simulation and multiple contact dynamic solubilisation tests to confirm procyanidin redissolution in an aprotic/protic solvent system. The results showed that separation of procyanidins in the aprotic/protic solvent system of Diol-NP-HPLC was governed by precipitation/redissolution mechanism, that could be extended to all known plant proanthocyanidin homopolymers, including hydrolysable tannins, if they are able to accomplish this condition. However, separation of monomer species, namely catechins and some hydroxybenzoic acids, was based on classic adsorption/partition mechanism. Other factors, such as analyte solubility, chromatographic conditions and sample preparation, that affect the viability of proanthocyanidin analysis by NP-HPLC were stand out and guidelines for its durable and reproducible use were defined.

From Nickel Ore to Ni Nanoparticles in the Extraction Process: Properties and Application

Laterite nickel ore is a mineral rock, which contains iron–nickel oxide compounds. One processing technology proposed to treat the ore is the Caron process. In general, the Caron process combines pyrometallurgical and hydrometallurgical stages. In the pyrometallurgical step, the ore mixed with reductant is heated up to 1800 °C in a rotary kiln-electric furnace to transform iron–nickel oxide into iron–nickel alloy. In the hydrometallurgical stage, nickel has to be dissolved selectively using ammonia solution (alkaline). The further process is aimed to separate and purify the nickel in ammonia solution using solvent extraction and precipitation. The disadvantages of the pyrometallurgical stage in the Caron process include high-energy consumption, low economic value, and technical problems such as partially melted material, which hinders the further process. While in the hydrometallurgical stage, the extensive use of ammonia causes an environmental impact. Selective reduction is proposed to solve problems in the pyrometallurgical stage. Selective reduction is a process favouring the formation of iron oxide to obtain high nickel content in an intermediate product with less energy consumption. An additive is added to the ore to reduce selectively the nickel and decrease the reaction temperature. To solve the environmental impact of ammonia, a novel and safer chemical is proposed as a substitute — the monosodium glutamate (MSG). Selective reduction combined with alkaline leaching using MSG is proposed as an alternative to the Caron method. Precipitation is employed further to purify the nickel that results in nickel nanoparticles with 90–95 wt.% purity.

Comparison of the Determination of Some Antihypertensive Drugs in Clinical Human Plasma Samples by Solvent Front Position Extraction and Precipitation Modes.

The determination of the selected antihypertensive drugs in human plasma samples with the novel solvent front position extraction (SFPE) technique is presented. The SFPE procedure combined with LC-MS/MS analysis was used for the first time to prepare a clinical sample containing the drugs mentioned above from different therapeutic groups. The effectiveness of our approach was compared with the precipitation method. The latter technique is usually used to prepare biological samples in routine laboratories. During the experiments, the substances of interest and the internal standard were separated from other matrix components using a prototype horizontal chamber for thin-layer chromatography/high-performance thin-layer chromatography (TLC/HPTLC) with a moving pipette powered by a 3D mechanism, which distributed the solvent on the adsorbent layer. Detection of the six antihypertensive drugs was performed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) in multiple reaction monitoring (MRM) mode. Results obtained by SFPE were very satisfactory (linearity R2 ≥ 0.981; %RSD ≤ 6%; LOD and LOQ were in the range of 0.06-9.78 ng/mL and 0.17-29.64 ng/mL, respectively). The recovery was in the range of 79.88-120.36%. Intra-day and inter-day precision had a percentage coefficient of variation (CV) in the range of 1.10-9.74%. The procedure is simple and highly effective. It includes the automation of TLC chromatogram development, which significantly reduced the number of manual operations performed, the time of sample preparation and solvent consumption.

Bioleaching of indium from spent light-emitting diode monitors and selective recovery followed by solvent extraction

The spent light emitting diode (LED) monitors are one of the fastest-growing waste streams that could provide indium, an essential element for the industry. This study presents a comprehensive strategy for indium extraction from spent LED monitors, including bioleaching followed by solvent extraction, stripping, and precipitation. Effects of A. thiooxidans and A. ferrooxidans inoculum percentage in mixed culture, pulp density, and time on indium, aluminum, and strontium bioleaching were investigated. In this regard, at optimized inoculum percentages (1.5 and 0.5% (v/v) of A. ferrooxidans and A. thiooxidans, respectively) and pulp density (60 g/L) at initial pH of 2, approximately 100% indium recovery was obtained in 18 days. The solubilized indium in the bioleaching solution has been extracted by the organic solvent of 20% (v/v) D2EHPA in kerosene. Following extraction, the stripping step was carried out to recover indium rather than iron selectively. The effect of two-phase contact time and aqueous to organic phase volume ratio in the extraction step and the acid type and concentration in the stripping step on indium and iron recovery percentages have been evaluated. For indium extraction, the optimum ratio of aqueous to organic phase volume and time were determined as 1 and 30 min, respectively, recovering 91.5% of indium. Using 5 M sulfuric acid has also resulted in an efficient stripping process. Finally, sodium hydroxide performed indium precipitation and a final precipitate of 94% (w/w) indium was obtained.

Non-regulated LC-MS/MS bioanalysis in support of early drug development: a Novartis perspective.

Scientifically qualified LC-MS/MS methods are essential for the determination of small molecule drug candidates and/or their metabolite(s) in support of various non-regulated safety assessment and in vivo absorption, distribution, metabolism and excretion studies in preclinical development. This articleoutlines an effective method development workflow to fit for this purpose. The workflow features a 'universal' protein precipitation solvent for efficient sample extraction, a mobile phase additive for managing chromatographic resolution and addressing carryoverand an internal standard cocktail to select the best analogue internal standard to track the analyte of interest in LC-MS/MS. In addition, good practices arerecommended to prevent bioanalytical pitfalls due to instability, non-specific bindingand dosing vehicle-induced matrix effect. Proper handling of non-liquid matrix isalso discussed.

Poly(ε-caprolactones) Initiated by Chiral Compounds: A New Protocol to Support Organocatalysts

This work investigates the support of organocatalysts in polyesters, a class of polymers seldom used for this purpose. The proposal is to use the hydroxyl groups present in the structure of the chosen chiral compounds to promote the polymerization of ε-caprolactone, generating the support and anchoring the organocatalyst in a single step. A very simple method, with acid catalysis, was employed, that showed versatility in generating supported catalysts with different structures and functional groups and modulating the mass of the materials to generate specific solubility characteristics. In this way, the catalysts can be solubilized in some organic solvents, such as dichloromethane, but at the end of the reaction, they can be recovered in a heterogeneous way, through precipitation in more apolar solvents. The materials were applied as organocatalysts on an aldol addition test reaction and the product could be obtained in excellent yields and good stereoselectivity. The polymer did not show signs of degradation after the reaction, proving to be robust and suitable for use in catalysis; however, a recycling process appears to be necessary for its reuse.

Tunable Magneto-Plasmonic Nanosensor for Sensitive Detection of Foodborne Pathogens.

Frequent outbreaks of food-borne pathogens, particularly E. coli O157:H7, continue to impact human health and the agricultural economy tremendously. The required cell count for this pathogenic strain of E. coli O157:H7 is relatively low and hence it is vital to detect at low colony forming unit (CFU) counts. Available detection methods, though sensitive, fall short in terms of timeliness and often require extensive sample processing. To overcome these limitations, we propose a novel magneto-plasmonic nanosensor (MPnS) by integrating surface plasmon resonance (SPR) properties with spin-spin magnetic relaxation (T2 MR) technology. We engineered MPnS by encapsulating several gold nanoparticles (GNPs) within the polymer-coating of iron oxide nanoparticles (IONPs). First, the polyacrylic acid (PAA)-coated IONPs were synthesized using a solvent precipitation method, then gold chloride solution was used to synthesize GNPs and encapsulate them within the PAA-coatings of IONPs in one step. A magnetic separation technique was used to purify the MPnS and the presence of GNPs within IONPs was characterized using transmission electron microscopy (TEM), energy dispersive x-ray spectroscopy (EDS), and other spectroscopic methods. The synthesized MPnS exhibits MR relaxation properties while possessing amplified optical properties than conventional GNPs. This allows for rapid and ultrasensitive detection of E. coli O157:H7 by SPR, T2 MR, and colorimetric readout. Experiments conducted in simple buffer and in milk as a complex media demonstrated that our MPnS-based assay could detect as low as 10 CFUs of this pathogenic strain of E. coli O157:H7 in minutes with no cross-reactivity. Overall, the formulated MPnS is robust and holds great potential for the ultrasensitive detection of E. coli O157:H7 in a simple and timely fashion. Moreover, this platform is highly customizable and can be used for the detection of other foodborne pathogens.