Precipitation Step Research Articles

In Vitro and In Vivo Hydrolytic Degradation Behaviors of a Drug-Delivery System Based on the Blend of PEG and PLA Copolymers.

This paper presents the in vitro and in vivo degradation of BEPO, a marketed in situ forming depot technology used for the formulation of long-acting injectables. BEPO is composed of a solution of a blend of poly(ethylene glycol)-block-poly(lactic acid) (PEG-PLA) triblock and diblock in an organic solvent, where a therapeutic agent may be dissolved or suspended. Upon contact with an aqueous environment, the solvent diffuses and the polymers precipitate, entrapping the drug and forming a reservoir. Two representative BEPO compositions were subjected to a 3-month degradation study in vitro by immersion in phosphate-buffered saline at 37 °C and in vivo after subcutaneous injection in minipig. The material erosion rate, as a surrogate of the bioresorption, determined via the depot weight loss, changed substantially, depending on the composition and content of polymers within the test item. The swelling properties and internal morphology of depots were shown to be highly dependent on the solvent exchange rate during the precipitation step. Thermal analyses displayed an increase of the depot glass transition temperature over the degradation process, with no crystallinity observed at any stage. The chemical composition of degraded depots was determined by 1H NMR and gel permeation chromatography and demonstrated an enrichment in homopolymers, i.e., free PLA and (m)PEG, to the detriment of (m)PEG-PLA copolymers in both formulations. It was observed that the relative ratio of the degradants within the depot is driven by the initial polymer composition. Interestingly, in vitro and in vivo results showed very good qualitative consistency. Taken together, the outcomes from this study demonstrate that the different hydrolytic degradation behaviors of the BEPO compositions can be tuned by adjusting the polymer composition of the formulation.

Direct Lithium Extraction Using Intercalation Materials.

Worldwide lithium demand has surged in recent years due to increased production of Li-ion batteries for electric vehicles and stationary storage. Li supply and production will need to increase such that the transition towards increased electrification in the energy sector does not become cost prohibitive. Many countries have taken policy steps such as listing Li as a critical mineral. Current commercial Li mining is mostly from dedicated mine sources, including ores, clays, and brines. The conventional ways to extract Li+ from those resources are through chemical processing and includes steps of calcination, leaching, precipitation, and purification. The environmental and economic sustainability of conventional Li processing has recently received increased scrutiny. Routes such as direct Li+ extraction may provide advantages relative to conventional Li+ extraction technologies, and one possible route to direct Li+ extraction includes leveraging intercalation materials. Intercalation material processing has recently demonstrated high selectivity towards Li+ as opposed to other cations. Reviews and reports of direct Li+ extraction with intercalation materials are limited, even as this technology has started to show promise in smaller-scale demonstrations. This paper will review selective Li+ extraction via intercalation materials, including both electrochemical and chemical methods to drive Li+ in and out, and efforts to characterize the Li+ insertion/deinsertion processes.

Resynthesis of cathode active material from heterogenous leachate composition produced by electric vehicle (EV) battery recycling stream

Massive growth of electric vehicle (EV) sales in recent years triggers the huge demands of certain elements for lithium-ion battery (LIB) production. To sustain the supply of the elements and contribute to its circularity, LIB recycling is one of the justified routes. Although hydrometallurgy is considered as the most common process in battery recycling, improvements are still required to make the recycling process cleaner by reducing the steps and minimizing the chemical use. To achieve this goal, co-precipitation method is proposed to produce cathode active metals (CAM) of Li, Ni, Mn and Co from the leach solution. As battery chemistry is evolving fast, in near future, the dominant LiNi1/3Mn1/3Co1/3O2 (LNMC 111) type will be replaced by other types with different NMC ratios. Hence, in this study, co-precipitation was tested to recover Li, Ni, Mn and Co from various leachates with different metal compositions, simulating leachates from different battery chemistries. A hydrometallurgy flowsheet comprising four precipitation steps for metal recoveries from leach solutions was developed. In the first stage, aluminium was removed as Al(OH)3 by increasing the pH of the leachate to 5.5. Cu was removed in the next stage as sulfide by adding sodium sulfide to the supernatant obtained in the first stage. In the third stage, Ni, Mn and Co were co-precipitated as hydroxide precursor by increasing pH of supernatant to 11. The results showed that >95% of Ni, >83% Co, and >42% of Mn could be precipitated from the leaching liquor. Finally, Li is recovered from the supernatant as carbonate precipitate by adding sodium carbonate. Ni,Mn,Co(OH)2 precursor was finally mixed with Li2CO3 precipitated and calcined to resynthesize CAM showing the potential of this process to close the loop of recycling.

Precipitation Using Organic Solvents for Purifying Lipase from Preussia africana

Aims: The present study aimed to purify a new lipase from the endophytic fungus Preussia africana (P. africana).
 Study Design: Lipases were produced through fermentation and precipitation using different organic solvents and characterized at optimal temperature and pH conditions.
 Place and Duration of Study: Assays were carried out at the Laboratory of Bioprocess at the Federal University of Alfenas between January and August, 2023.
 Methodology: Enzymes were produced via submerged fermentation. After fermentation, the broth was filtered and lyophilized so that enzymes were concentrated. Organic solvents (methanol, ethanol, isopropanol and acetone) were used at 10 and 25°C for lipase precipitation. A second precipitation step was investigated in a supernatant: solvent ration ranging from 1:3 to 1:2 (v/v) and temperatures between 10°C and 25°C. Optimal temperature and pH conditions for the hydrolytic activity of precipitated lipase were also found.
 Results: Acetone and isopropanol were more efficient in precipitating lipase while maintaining its catalytic activity, as specific activities of 211.34 ± 0.05 and 179.50 ± 0.08 U/mg were achieved, respectively. For the second precipitation step, acetone in a supernatant: solvent ratio of 1:2 (v/v) at 10°C achieved optimal performance, as purification factor of 1.89 ± 0.01 and recovered activity of 93.45% were found. Maximum hydrolytic activity of 72.80 ± 1.29 U/mL was observed using olive oil as substrate at pH between 7 and 8 and 37°C.
 Conclusion: The use of acetone at 10°C in two precipitation steps proved to be a more robust strategy for P. africana lipase precipitation in the purification process.

The role of chitosan in enhancing the solubility and antibacterial activity of emodin against drug-resistant bacteria

Similar to most anthraquinone compounds, the pharmacological properties of emodin are limited because of its low water solubility. In this study, the formulation of chitosan and emodin (EMD/CS) was prepared by a bottom-up method with precipitation and sonication steps in order to enhance the solubility of emodin. Thanks to the interactions of oxygen-and nitrogen-containing groups in chitosan with emodin molecules, the solubility of emodin in the formulation was remarkably increased to 0.5 mg/mL. The EMD/CS particles were well dispersed and distributed in a range of sub-micrometer with an average particle size of 342 nm. The EMD/CS formulation exhibited synergic antibacterial activity of emodin and chitosan, against drug-resistant bacterial strains, namely Methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli O157:H7 (E. coli O157:H7). When the compositions of emodin and chitosan increased, the antibacterial effectiveness of the EMD/CS formulation increased. The EMD/CS formulation with compositions of 0.5 mg/mL of emodin and 9.0 mg/mL of chitosan could significantly inhibit the proliferation of E. coli O157:H7. Meanwhile, the EMD/CS formulation with a lower concentration of emodin (0.4 mg/mL) and chitosan (7.2 mg/mL) could cause an extermination effect on MRSA. The enhanced solubility of EMD/CS formulation suggests that this formulation can be a potential candidate for the treatment of infectious diseases caused by drug-resistant bacterial pathogens.

Evaluation of a novel chlorine dioxide-based packaging technology to reduce human enteric virus contamination on refrigerated tomatoes and blueberries

IntroductionChlorine dioxide (ClO2) is a promising antimicrobial with various food applications, one of those being inclusion in packaging. The purpose of this study was to evaluate a novel ClO2-based antimicrobial packaging system (InvisiShield™) for its efficacy against human norovirus (hNoV) and hepatitis A virus (HAV) in refrigerated fresh produce.MethodsGrape tomatoes or blueberries were placed in polypropylene trays and selectively inoculated with 6.0 log10 hNoV Genome Equivalent Copies (GEC; 20% stool suspension) or 6.2 log10 HAV GEC (cell culture lysate). Trays were heat sealed with a three-phase polymer film consisting of a base, channeling agent, and the ClO2 active (treatment); or control (no active) film and stored at 7°C for 24, 48 h, and 7 days. At each timepoint, the product was collected and processed for virus concentration using the sequential steps of elution and polyethylene glycol precipitation. Viruses in extracts were quantified using RNase-RT-qPCR.Results and discussionLog10 reductions (LR) in hNoV GEC for tomatoes were 2.2 ± 1.3, 2.9 ± 0.7, and 3.6 ± 0.3, after 24, 48 h and 7 days, respectively. For blueberries, hNoV LR were 1.4 ± 0.7, 1.7 ± 0.5, and 2.7 ± 0.2 GEC, respectively. Hepatitis A virus GEC LR were 0.4 ± 0.2, 1.0 ± 0.1, and 2.1 ± 0.7 for tomatoes, and 0.1 ± 0.2, 1.2 ± 0.4, and 3.2 ± 0.2 for blueberries, after 24, 48 h and 7 days, respectively. Position of the fruit in the tray did not affect inactivation (p > 0.05). Sensory analysis on the treated tomato products revealed no statistically significant difference in appearance, flavor and texture attributes compared to the control. This novel ClO2-based antimicrobial packaging system effectively reduced concentrations of hNoV and HAV, as evaluated using reduction in GEC as proxy for infectivity, on grape tomatoes and blueberries after one day, with efficacy improving over 7 days of refrigerated storage. This technology shows promise as an antiviral treatment as applied to refrigerated fresh produce items.

The CombE-IDMS Assay as an Alternate Potency Method for Adjuvanted Quadrivalent Influenza Vaccines.

The potency of all currently licensed inactivated influenza viral vaccines is assayed by the single radial immunodiffusion (SRID) method. SRID relies upon antisera and reference antigen reagents which are produced, standardized, and distributed in the mass quantities needed for vaccine manufacturers only after a significant amount of time has elapsed from the seasonal strain recommendations issued by the WHO; this time delay is exacerbated under conditions of an emerging pandemic. Previously, the limited trypsin digestion isotope dilution mass spectrometry (LTD-IDMS) method, which does not require antisera or reference antigens, demonstrated comparable quantitation of immunologically active hemagglutinin, the primary viral antigen, to SRID in stressed vaccine materials. Here, we demonstrate a streamlined improvement to the LTD-IDMS method by eliminating the need for its precipitation and washing steps, saving time and labor in the sample preparation process while paving the way for plate-based high-throughput analysis. This is accomplished using dissimilar proteases in the pretreatment (a combination of chymotrypsin and elastase) and analytical (trypsin) digestion steps so that any pretreatment digests will not cause interference while monitoring analytical tryptic digests by IDMS. The combination of enzymes (CombE)-IDMS method is tested alongside LTD-IDMS and SRID for the first time on MF59 adjuvanted seasonal cell-based quadrivalent influenza vaccines (aQIVc) under stressed conditions of heating, oxidation, lowered and elevated pH, and freeze-thaw. Overall, a correlation in the degradation trend is observed between CombE-IDMS and SRID in the four strains of the quadrivalent formulation, highlighting the method's stability indicating capability as a rapid alternate potency assay in a highly complex formulation of aQIVc.

A new phosphate purification method for igneous weathering profiles.

The oxygen isotope composition of phosphate (δ18 OPO4 ) is widely employed for reconstructing paleotemperature and tracing biogeochemical phosphorus cycling. However, existing phosphate purification protocols do not work well for igneous rocks and igneous weathering profiles (IWPs). A reliable purification method is needed for measuring δ18 OPO4 in these materials. Our phosphate purification method includes two steps of cation exchange resin treatment separated by a step of calcium phosphate precipitation (R-Ca-R method). In addition, the silver phosphate precipitation in our procedure is featured by slow evaporation to crystallization until the appearance of ammonium nitrate or silver nitrate crystals. We evaluated our methods on weathered and pristine igneous rocks, phosphorite rocks, KH2 PO4 , and (NH4 )2 HPO4 solutions. Our purification method converted over 99.9% phosphate in solution to calcium phosphate, which can be easily decalcified by cation resin. The improved silver phosphate precipitation method produced high phosphate yields (97.1%-99.5%) and retained original δ18 OPO4 within analytical uncertainty (2σ = 0.6‰). We applied the purification and precipitation method on five igneous rocks and IWPs, and obtained δ18 OPO4 values ranging from 6.4‰ to 8.0‰. Duplicate phosphate extractions yielded δ18 OPO4 values differing by less than 0.3‰. We developed a new phosphate purification method that is applicable to phosphate extraction in igneous rocks and IWPs. We also proposed a reliable indicator for the termination of silver phosphate precipitation. Our method can achieve high phosphate yield and reproducible δ18 OPO4 value.

Comparing organic solvents in a combined water precipitation and liquid–liquid extraction process to recover lignin and furanics from a lactic acid: choline chloride deep eutectic solvent used as cooking liquor for cooking of spruce

Extracting and purifying lignin from wood without compromising cellulose quality is a challenging process. Lactic acid: choline chloride is a deep eutectic solvent (DES) that has been identified as acceptable delignification solvent, producing lignin and hemicellulose as byproducts to the cellulose. Hemicellulose is partly transformed into furanic compounds (such as furfural and 5-HMF). While the larger lignin can be obtained by water precipitation from DES, smaller lignin molecules and furanics can be recovered by liquid–liquid extraction (LLX), either directly or after precipitation of the larger lignin molecules. The presence of water in the DES after water precipitation reduced the mutual miscibility with the solvents, allowing the use of a wider range of solvents in the LLX process. In the precipitation step, all the larger molecular weight lignin (Mw > 5000 Da) can be recovered when adding at least 3.5:1 [g/g] water to DES-black liquor. For the LLX step, guaiacol was found as suitable alternative to the previously published 2-methyltetrahedrofuran (2-MTHF). In addition, here we report the use of 2,2,5,5-Tetramethyl oxolane (TMO), a recent addition to the palette of (potentially) bio-based solvents. The distribution coefficients of smaller lignin molecules and furanics in LLX with guaiacol, TMO and 2-MTHF were compared, revealing that smaller lignin molecules (500–5000 Da) can be recovered with a reasonable distribution coefficient by 2-MTHF and guaiacol. Furfural showed distribution coefficients of at least 1.27 in all three solvents. Guaiacol and TMO both showed a significantly lower lactic acid leaching than 2-MTHF. This makes them potential alternatives for 2-MTHF in this technique.Graphical abstract

Preliminary Flowsheet Development for Mixed Rare Earth Elements Production from Apatite Leaching Aqueous Solution Using Biosorption and Precipitation

A flowsheet was developed to extract mixed Rare Earth Elements (REEs) from an aqueous solution generated by nitric acid leaching of apatite concentrate. In this study, Platanus orientalis (P. orientalis) leaf powder was employed in the biosorption process to purify the pregnant leach solution. The sorption and desorption processes were investigated and optimized. The results demonstrated the successful extraction of REEs from the pregnant leach solution using the biosorbent. Hydrochloric acid effectively desorbed REEs from the loaded P. orientalis leaf powder. Thermodynamic studies indicated that REEs’ sorption on P. orientalis leaf powder was an endothermic and spontaneous process. Precipitation and calcination steps yielded mixed rare earth oxides (REOs) with an assay of approximately 87%. The final product, mixed REOs, can be further refined through releaching and a secondary impurity removal stage prior to entering the individual REE separation process. Alternatively, it can be fed directly into the solvent extraction process or alternative technologies to obtain individual heavy and light REEs.

Preparation of restricted-access boronate affinity adsorbent with excellent anti-protein adsorption property for directly extracting small cis-diol molecules from biological matrices

Boronate affinity adsorbents are of great promise in the enrichment of small cis-diol-containing molecules (cis-diols) from biological matrices. This work develops a restricted-access boronate affinity mesoporous adsorbent, in which boronate sites are only distributed on the internal surface of mesopores and the external surface is a strongly hydrophilic layer. The adsorbent has high binding capacities (30.3 mg g−1, 22.9 mg g−1 and 14.9 mg g−1 for dopamine, catechol and adenosine, respectively) in spite of removal of the boronate sites on the external surface of adsorbent. The adsorption specific of adsorbent towards cis-diols was assessed by dispersive solid-phase extraction (d-SPE) method, and the results show that the adsorbent can selectively extract small cis-diols in the biosamples while exclude proteins completely. Under the optimal d-SPE, the nucleosides and cis-diol drugs in human serum were successfully analyzed by coupling d-SPE with high-performance liquid chromatography. Where, the detection limits are between 6.1 and 13.4 ng mL−1 for four nucleosides, and 24.9 and 34.3 ng mL−1 for two cis-diol drugs; the relative recoveries of all the analytes vary from 84.1% to 110.1% (RSDs <13.4%, n = 6). The results indicate that the adsorbent can directly treat the real biosamples without the necessary protein precipitation steps in advance, thus simplifying the analysis process.

Determination of cannabinoids in 50 μL whole blood samples by online extraction using turbulent flow chromatography and LC-HRAM-Orbitrap-MS: Application on driving under the influence of drugs cases.

The analysis of cannabinoids in whole blood is usually done by traditional mass spectrometry (MS) techniques, after offline cleanup or derivatization steps which can be lengthy, laborious, and expensive. We present a simple, fast, highly specific, and sensitive method for the determination of Δ9 -tetrahydrocannabinol (THC), cannabidiol (CBD), cannabinol (CBN), 11-hydroxy-Δ9 -tetrahydrocannabinol (11-OH-THC), and 11-nor-9-carboxy-Δ9 -tetrahydrocannabinol (THC-COOH) in 50 μL whole blood samples. After the addition of deuterated internal standards (IS) and a simple protein precipitation step, an online extraction of sample supernatants using turbulent flow chromatography (TurboFlow-Thermo Scientific) was carried out. Analytes were separated on a C18 analytical column and detected by LC-HRAM-Orbitrap-MS using a Thermo Scientific Q Exactive Focus MS system. MS detection was performed in polarity switching and selected ion monitoring (SIM) modes using five specific acquisition windows, at a resolution of 70,000 (FWHM). Total run time was about 10min including preanalytical steps. Method validation was carried out by determining limit of detection (LOD), lower limit of quantitation (LLOQ), linearity range, analytical accuracy, intra-assay and interassay precision, carry-over, matrix effect, extraction recovery, and selectivity, for all analytes. Measurement uncertainties were also evaluated, and a decision rule was set with confidence for forensic purposes. The method may become suitable for clinical and forensic toxicology applications, taking advantage of the small matrix volume required, the simple and cost-effective sample preparation procedure, and the fast analytical run time. Performances were monitored over a long-term period and tested on 7620 driving under the influence of drugs (DUID) samples, including 641 positive samples.

An LC–MS/MS Analytical Method for Quantifying Tepotinib in Human Liver Microsomes: Application to In Vitro and In Silico Metabolic Stability Estimation

Tepotinib (MSC2156119) is a potent mesenchymal–epithelial transition (MET) factor inhibitor, a receptor tyrosine kinase that plays a crucial role in promoting cancer cell malignant progression. Adverse effects of tepotinib (TEP), such as peripheral edema, interstitial lung disease, nausea and diarrhea, occur due to drug accumulation and lead to termination of therapy. Therefore, the in silico and experimental metabolic susceptibility of TEP was investigated. In the current work, an LC-MS/MS analytical method was developed for TEP estimation with metabolic stability assessment. TEP and lapatinib (LTP) used as internal standards (ISs) were separated on a reversed-phase C18 column using the isocratic mobile phase. Protein precipitation steps were used to extract TEP from the human liver microsome (HLM) matrix. An electrospray ionization multi-reaction monitoring (MRM) acquisition was conducted at m/z 493→112 for TEP, at m/z 581→350, and 581→365 for the IS. Calibration was in the range of 5 to 500 ng/mL (R2 = 0.999). The limit of detection (LOD) was 0.4759 ng/mL, whereas the limit of quantification (LOQ) was 1.4421 ng/mL. The reproducibility of the developed analytical method (inter- and intra-day precision and accuracy) was within 4.39%. The metabolic stability of TEP in HLM was successfully assessed using the LC-MS/MS method. The metabolic stability assessment of TEP showed intermediate Clint (35.79 mL/min/kg) and a moderate in vitro t1/2 (22.65 min), proposing the good bioavailability and moderate extraction ratio of TEP. The in silico results revealed that the N-methyl piperidine group is the main reason of TEP metabolic lability. The in silico Star Drop software program could be used in an effective protocol to confirm and propose the practical in vitro metabolic experiments to spare resources and time, especially during the first stages for designing new drugs. The established analytical method is considered the first LC-MS/MS method for TEP estimation in the HLM matrix with its application to metabolic stability assessment.

Rapid high performance liquid chromatography method for erlotinib quantification in vitro: Application to study the effect of resveratrol on metabolism and cellular uptake of erlotinib.

Erlotinib is a selective epidermal growth factor receptor inhibitor that is used for the treatment of non-small cell lung cancer and pancreatic cancer. Its metabolism is mainly mediated by cytochrome P450 3A (CYP 3A). Resveratrol, a natural compound found in many plants and supplements, is known to inhibit CYP3A enzyme, therefore, it may act as an inhibitor for the metabolism of erlotinib. Development of a rapid high performance liquid chromatography with photodiode array detection (HPLC-PDA) method for the quantification of erlotinib in liver microsomes and cancer cells and its application to study resveratrol effect on metabolism and cellular uptake of erlotinib. HPLC-PDA was used to develop an efficient bioanalytical method with a 2.5-min runtime preceded by a simple protein precipitation step. The method was validated according to the European Medicines Agency guidelines. Erlotinib metabolic stability and resveratrol effect on erlotinib metabolite formation were evaluated in rat liver microsomes. Furthermore, the method was used to measure the intracellular concentrations of erlotinib in cancer colorectal cells and investigating resveratrol effect on the cellular uptake of erlotinib. A rapid HPLC-PDA method was developed and validated for the first time to address potential drug interaction of erlotinib with resveratrol. Resveratrol was a strong inhibitor of erlotinib metabolism in vitro with IC50 = 4.03 μM. Resveratrol, however, had no effect on erlotinib cellular uptake after 1h incubation in human colorectal cancer cells. The study suggests that resveratrol may produce a potential herb-drug interaction with erlotinib at the metabolism level and should be investigated in patients in the clinic.

Chromatography-free purification of (+)-dihydromyricetin through three-step tandem cavitation fractional precipitation

In this study, a chromatography-free purification process through a three-step tandem cavitation fractional precipitation (CFP) was developed to obtain high-purity (+)-dihydromyricetin. Ultrasound and negative pressure were introduced simultaneously into three types of precipitation solutions (acetone-water, methanol-water, and ethanol-water) and precipitation was performed for 30 min. The purity of (+)-dihydromyricetin after the three-step tandem CFP was >98 % and the overall yield was >90 %. In addition, the impurity removal patterns at each precipitation step were observed through reverse phase-high performance liquid chromatography analysis, and the chemical structure of (+)-dihydromyricetin finally purified through the three-step tandem CFP was confirmed through Fourier-transform infrared spectroscopy analysis.

Recovery of Lithium from Simulated Nanofiltration-Treated Seawater Desalination Brine Using Solvent Extraction and Selective Precipitation

ABSTRACT The world's seas and oceans contain vast amounts of lithium, but the low concentration hereof renders solvent extraction impractical for its recovery. By contrast, seawater desalination brine, after treatment by nanofiltration, contains a roughly tenfold greater concentration of lithium than raw seawater. Hence, lithium can be effectively recovered from such streams using solvent extaction. Compared with other techniques to sequester lithium from dilute solutions, solvent extraction offers the advantages of simple operations, robust and well-established technology and high recovery yields. Thus, we propose a solvent-extraction based process to recover lithium from seawater desalination brine, treated by nanofiltration. The first step comprises the removal of magnesium and calcium using methyltrioctylammonium neodecanoate in p-cymene. This is followed by a lithium extraction step using the extractants Mextral 54–100 and Cyanex 923 in Shellsol D70 diluent. The lithium extract is then scrubbed with water and stripped with hydrochloric acid. Subsequently, residual alkaline earth metals are removed with sodium hydroxide in ethanol and finally lithium is precipitated using sodium carbonate. The solvent extraction, scrubbing and stripping steps were demonstrated on mini-pilot scale in continuous countercurrent mode (in mixer-settlers), while the precipitation steps were demonstrated in batch. The process was found to have an overall yield of 74%, affording a lithium carbonate product with a purity of 97 wt%.

Standard addition method (SAM) in LC-MS/MS to quantify gluten-derived metabolites in urine samples

A tight adherence to a gluten-free diet (GFD), the most effective treatment currently available for celiac disease, is important to reduce symptoms, avoid nutritional deficiencies and improve quality of life in celiac patients. The development of analytical methods allowing detecting gluten exposure due to occasional or involuntary food transgressions could represent a useful tool to monitor patient habits and conditions and prevent long-term complications. The aim of this work was to develop and validate an approach based on the standard addition methodology (SAM) for the detection and quantification of two main metabolites of alkylresorcinols, 3,5-dihydroxybenzoic acid (DHBA) and 3-(3,5-dihydroxyphenyl)-propanoic acid (DHPPA), whose presence in urine samples is related to the intake of gluten-containing foods. Analytically, the method consisted of a protein precipitation step followed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analysis. The chromatographic method involved the use of a hydrophilic interaction liquid chromatography (HILIC) in a direct phase approach; LC-MS/MS analyses were performed in selected reaction monitoring (SRM) mode. Manipulation and instrumental errors were normalised using stable isotopic standards (ISs). The SAM approach here described requires less than 1 mL of urine per sample, thus greatly reducing the sample volume needed. Noteworthy, despite the small cohort of samples analysed, our data allowed to identify a potential “threshold” value, around 200 ng/mL for DHBA and 400 ng/mL for DHPPA, to discriminate between a GFD and a gluten rich diet (GRD).

Chemical separation and measurement of platinum activation products

A method has been developed to purify and measure platinum radioisotopes in the presence of fission products and environmental constituents. The method uses a combination of cation exchange and anion exchange chromatography and selective precipitation steps to remove other radioisotopes from the sample. The addition of stable platinum carrier allows for a gravimetric determination of the chemical yield of the procedure. Overall, the method is fast, simple, and potentially applicable for rapid turnaround of unknown samples. Using this method, multiple platinum radioisotopes were measured in two different irradiation experiments. The measured ratios of the platinum radioisotopes clearly reflect the neutron spectrum of the irradiation, suggesting that platinum radioisotopes could be valuable signatures in nuclear forensic analyses.

Fractionation of κ-casein from caprine micellar caseins using differential precipitation

The effects of potentially important processing conditions at each step of differential precipitation on the yield and purity of κ-casein fractionated from caprine micellar casein concentrate (MCC) were investigated. The optimal conditions were: rehydrating (3% casein) MCC using homogenisation followed by dissociating micelles at pH 11.0; complexing caseins using 45 mm added Ca at 25 °C for 60 min, followed by precipitating β-/αS-caseins using 2 m acetic acid at pH 7.0 again at 25 °C for 60 min. Two fractionation cycles were used with 50 mm added Ca for the second cycle, followed by precipitating κ-casein at pH 3.8 and 50 °C. To increase processing capacity for scale-up, increased casein concentrations of 4–7% along with 60 mm added Ca resulted in comparable yields and purity of the κ-casein. Maximum yield and purity of 84.6% and 84.4%, respectively, were achieved for κ-casein from the MCC dispersions at 4% casein.

Recovery of battery-grade products from mixed spent LiFePO4/LiMn2O4 cathodes via slurry electrolysis

A facile and efficient of two-stage slurry electrolysis process comprising of precipitation and separation steps was proposed to recover different metals from the mixed spent LFP and LMO cathodes simultaneously. Benefitting from the presence of LFP, the leaching efficiency of LMO was enhanced in the first-stage slurry electrolysis. Fe and Li in the lixivium can then be easily recovered as pure FePO4 and battery-grade Li2CO3 in the precipitation and separation steps, respectively. Finally, the battery-grade MnO2 is produced in the second-stage slurry electrolysis. The total recovery rates of Li, Mn, and Fe are as high as 89.83 %, 88.69 % and 94.42 %, respectively. In addition, the integrated process of the two-stage slurry electrolysis is simple and easy to perform on industrial scale and introduces remarkable economic and environmental benefits.