Multivariate optimization and comparison between conventional extraction (CE) and ultrasonic-assisted extraction (UAE) of carotenoid extraction from cashew apple

Carotenoids are an essential component of cashew and can be used in pharmaceuticals, cosmetics, natural pigment, food additives, among other applications. The present work focuses on optimizing and comparing conventional and ultrasound-assisted extraction methods. Every optimization step took place with a 1:1 (w:w) mixture of yellow and red cashew apples lyophilized and ground in a cryogenic mill. A Simplex-centroid design was applied for both methods, and the solvents acetone, methanol, ethanol, and petroleum ether were evaluated. After choosing the extractor solvent, a central composite design was applied to optimize the sample mass (59–201 mg) and extraction time (6–34 min). The optimum conditions for the extractor solvent were 38% acetone, 30% ethanol, and 32% petroleum ether for CE and a mixture of 44% acetone and 56% methanol for UAE. The best experimental conditions for UAE were a sonication time of 19 min and a sample mass of 153 mg, while the CE was 23 min and 136 mg. Comparing red and yellow cashews, red cashews showed a higher carotenoid content in both methodologies. The UAE methodology was ca. 21% faster, presented a more straightforward composition of extracting solution, showed an average yield of superior carotenoid content in all samples compared to CE. Therefore, UAE has demonstrated a simple, efficient, fast, low-cost adjustment methodology and a reliable alternative for other applications involving these bioactive compounds in the studied or similar matrix.     

Rapid qualitative profiling and quantitative analysis of Juglandis Mandshuricae Cortex and seven flavonoids by ultra-high performance liquid chromatography–quadrupole/orbitrap high-resolution mass spectrometry

Juglandis Mandshuricae Cortex is the bark of Juglans mandshurica Maxim., which has been used as a folk medicine plant in China and India. In this study, an ultra-high performance liquid chromatography–quadrupole/orbitrap high-resolution mass spectrometry method was developed to clarify and quantify the chemical profiling of Juglandis Mandshuricae Cortex rapidly. A total of 113 compounds were characterized. Among them, seven flavonoids were simultaneously quantified in 15 min, including myricetin, myricetrin, taxifolin, kaempferol, quercetin, quercitrin, and naringenin. The method was validated for accuracy, precision, and the limits of detection and quantification. All calibration curves showed a good linear relationship (r > 0.9990) within test ranges. The intra- and inter-day relative standard deviations were less than 2.16%. Accuracy validation showed that the recovery was between 95.6 and 101.3% with relative standard deviation values below 2.85%. The validated method was successfully applied to determine the contents of seven flavones in Juglandis Mandshuricae Cortex from seven sources and the contents of these places were calculated respectively. This method provides a theoretical basis for further developing the medicinal value of Juglandis Mandshuricae Cortex.     

Enhanced thermoelectric performance of PEDOT:PSS films via ionic liquid post-treatment

Thermoelectric(TE)energy harvesting can effectively convert waste heat into electricity,which is a crucial technology to solve energy concerns.As a promising candidate for energy conversion,poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)has gained significant attention owing to its easy doping,high transparency,and solution processability.However,the TE performance of PEDOT:PSS still needs to be further enhanced.Herein,different approaches have been applied for tuning the TE properties:(i)direct dipping PEDOT:PSS thin films in ionic liquid;(ii)post-treatment of the films with concentrated sulfuric acid(H₂SO₄),and then dipping in ionic liquid.Besides,the same bis(trifluoromethanesulfonyl)amide(TFSI)anion and different cation salts,including 1-ethyl-3-methylimidazolium(EMIM+)and lithium(Li+),are selected to study the influence of varying cation types on the TE properties of PEDOT:PSS.The Seebeck coefficient and electrical conductivity of the PEDOT:PSS film treated with H2SO4EMIM:TFSI increase simultaneously,and the resulting maximum power factor is 46.7μW·m^-1·K^-2,which may be attributed to the ionic liquid facilitating the rearrangement of the molecular chain of PEDOT.The work provides a reference for the development of organic films with high TE properties.     

A combination of dispersive liquid–liquid microextraction and surface plasmon resonance sensing of gold nanoparticles for the determination of ziram pesticide

We have developed a reliable, fast, and highly sensitive analytical method utilizing dispersive liquid–liquid microextraction and gold nanoparticles probes for ziram (zinc bis(dimethyldithiocarbamate)) determination. The method is based on the in situ formation of gold nanoparticles in carbon tetrachloride as an organic phase. It was found that the trace levels of ziram influenced the formation of gold nanoparticles, leading to absorbance change of a sedimented phase. The results of the colorimetric ziram determination were in the concentration range of 0.12–2.52 ng/mL with a limit of detection of 0.06 ng/mL. The formation of the stable and dispersed gold nanoparticles in the organic phase provides a good precision for dispersive liquid–liquid microextraction method, resulting in the relative standard deviation of 3.8 and 1.2% for 0.56 and 1.58 ng/mL of ziram, respectively. This method has been successfully used for the ziram determination in samples of well and river water, soil, potato, carrot, wheat, and paddy soil.     

Coupling nanoliter high‐performance liquid chromatography to inductively coupled plasma mass spectrometry for arsenic speciation

Nanoliter high‐performance liquid chromatography shows low consumption of solvents and samples, offering one of the best choices for arsenic speciation in precious samples in combination with inuctively coupled plasma mass spectrometry. A systematic investigation on coupling nanoliter high‐performance liquid chromatography to inductively coupled plasma mass spectrometry from instrument design to injected sample volume and mobile phase was performed in this study. Nanoflow mobile phase was delivered by flow splitting using a conventional high‐pressure pump with reuse of mobile phase waste. Dead volume was minimized to 60 nL for the sheathless interface based on the previously developed nanonebulizer. Capillary columns for nanoliter high‐performance liquid chromatography were found to be sensitive to sample loading volume. An apparent difference was also found between the mobile phases for nanoliter and conventional high‐performance liquid chromatography. Baseline separation of arsenite, arsenate, monomethylarsenic, and dimethylarsenic was achieved within 11 min on a 15 cm C₁₈ capillary column and within 12 min on a 25 cm strong anion exchange column. Detection limits of 0.9–1.8 μg/L were obtained with precisions variable in the range of 1.6–4.2%. A good agreement between determined and certified values of a certified reference material of human urine (GBW 09115) validated its accuracy along with good recoveries (87–102%).     

One‐pot synthesis of a multi‐template molecularly imprinted polymer for the extraction of six sulfonamide residues from milk before high‐performance liquid chromatography with diode array detection

A highly selective molecularly imprinted polymer sorbent was synthesized and employed for the simultaneous determination of six sulfonamide antibiotic residues (sulfanilamide, sulfacetamide, sulfadiazine, sulfathiazole, sulfamerazine, and sulfamethizole) in milk samples. Multi‐analyte imprinted particles were used as a sorbent in solid‐phase extraction. Sulfonamides were separated on a high‐performance liquid chromatography column (Merck–Lichrospher RP18e, 5 μm 250 × 4 mm) and further identified and quantified by diode array detection. Several parameters including required loading of the molecularly imprinted polymer sorbent, mass of milk, volume, and type of elution solvent, as well as time for absorption and elution were investigated to obtain optimal experimental conditions. For comparison purpose, a non‐imprinted polymer was applied under the optimum conditions. The validation study according to the European Union Decision 2002/657/EC was based on the investigation of linearity, selectivity, stability, limits of detection and quantitation, decision limit, detection capability, trueness, precision, and ruggedness according to Youden's approach. The decision limit and detection capability values in the milk were achieved from 101.9 to 113.5 μg/kg and from 114.4 to 135.4 μg/kg, respectively, depending on the target sulfonamide drug. Finally, the optimized protocol was successfully applied to commercial milk samples and human breast milk.     

Simultaneous quantification of five biogenic amines based on LC–MS/MS and its application in honeybee venom from different subspecies

The use of honeybee venom in traditional medicine is increasing due to its unexpected beneficial effects in the treatment of diseases. In this study, a simple and environmentally friendly sample preparation procedure was developed to quantify five biogenic amines—histamine, 5-hydroxytryptamine, dopamine, adrenaline, and noradrenaline—in honeybee venom using high-performance liquid chromatography tandem mass spectrometry. The instrument and sample preparation method were optimized to achieve stable, sensitive, and accurate quantification of the five biogenic amines. The peak purities of five biogenic amines in bee venom were examined using a diode array detector to ensure that endogenous impurities will not interfere with biogenic amines during the chromatographic separation procedure. The correlation coefficient of each compound was higher than 0.998 in the range of 0.5–1000 ng/mL. The limits of detection and quantification of the developed method ranged between 0.09 and 0.17, and 0.3 and 0.59 μg/g, respectively. The average recoveries of spiked biogenic amines with different concentrations were higher than 70.95%, and the intra- and intermediate-day precisions were lower than 7.51% and 10.17%, respectively. The carry-over between each injection and the stability of the target analytes were also evaluated to ensure the effectiveness of this method. The data obtained are presented in various formats, including boxplot, heat map, and principal component analysis diagram, to visualize the differences in the biogenic amine contents of the honeybee venoms from different subspecies. This method hopes to provide the opportunity to distinguish the bee venom produced by different subspecies.     

A novel LC–MS/MS method for the determination of ziritaxestat in rat plasma and its pharmacokinetic study

Ziritaxestat is a first-in-class autotoxin inhibitor. The purpose of this study was to develop a liquid chromatography/electrospray ionization tandem mass spectrometric (LC–MS/MS) method for the determination of ziritaxestat in rat plasma. The plasma sample was deproteinated using acetonitrile and then separated on an Acquity BEH C₁₈ column with water containing 0.1% formic acid and acetonitrile as mobile phase, which was delivered at 0.4 ml/min. Ziritaxestat and the internal standard (crizotinib) were quantitatively monitored with precursor-to-product transitions of m/z 589.3 > 262.2 and m/z 450.1 > 260.2, respectively. The total running time was 2.5 min. The method showed excellent linearity over the concentration range 0.5–2000 ng/ml, with correlation coefficient >0.9987. The extraction recovery was >82.09% and the matrix effect was not significant. Inter- and intra-day precisions (RSD) were <11.20% and accuracies were in the range of −8.50–7.45%. Ziritaxestat was demonstrated to be stable in rat plasma under the tested conditions. The validated LC–MS/MS method was successfully applied to study the pharmacokinetic profiles of ziritaxestat in rat plasma after intravenous and oral administration. Pharmacokinetic results demonstrated that ziritaxestat displayed a short half-life (~3 h) and low bioavailability (20.52%).     

Accurate,sensitive determination of omega-6 and omega-3 polyunsaturated fatty acids in human plasma,urine samples

Quantitative determination of omega-6 and omega-3 polyunsaturated fatty acids in human plasma and urine with high accuracy and precision provides significant information to monitor the underlying etiology of several diseases. In this regard, liquid chromatography-mass spectrometry is a good choice owing to its great selectivity and sensitivity. Additionally, the hybrid quadrupole–time of flight–mass spectrometer systems provides easy identification of target compounds with superior mass measurements. In this study, an analytical method has been developed for simple, accurate and simultaneous determination of linoleic acid, arachidonic acid, docosahexaenoic acid and eicosapentaenoic acid in a short chromatographic analysis period. The developed method is suitable for the quantitative detection of these four compounds with detection limits ranging between 1.1–3.0 ng ml⁻¹ and its applicability was assessed in human urine and plasma samples. As a result, acceptable accuracy (between 83 and 111%) and good precision (<6%) were obtained for target compounds using matrix matching calibration strategy.