Identification,quantification and Chrastil modelling of wheat straw wax extraction using supercritical carbon dioxide

Supercritical carbon dioxide (scCO₂) can be used as a “green” selective solvent for extractions of wheat straw waxes. For the first time, the crude extraction yields of wheat straw waxes and the yields of a single high value group of components (wax esters) using various scCO₂ conditions (305.15 to 373.15 K and 7.5 to 40 MPa) have been modelled using the Chrastil equation (Chrastil, 1982). The model accurately predicts both the crude yield and percentage of valuable wax esters within the extracts enabling maximum extraction efficiency. The key compounds within the waxes (fatty acids, sterols, fatty alcohols, wax esters, β-diketones and alkanes) have been identified and quantified. This study highlighted that, 14,16 hentriacontanedione was extracted at critical temperature and pressure in concentrations of 1000 μg.g⁻¹ straw. This molecule could demonstrate significant potential as a natural chelate for metal recovery and also in the formation of super-hydrophobic coatings.     

Determination of macrolides in livestock excreta by syringe purification coupled with liquid chromatography tandem mass spectrometryEI北大核心CSCD

A method of syringe-dispersive solid-phase extraction combined with ultrahigh performance liquid chromatography with tandem mass spectrometry for the simultanous determination of 10 macrolides in manurebased fertilizers was developed. After extraction with methanol and acetonitrile,the extracts were purified by insyringe dispersion solid-phase extraction in syringes pre-filled with 60 mg PSA and 30 mg C18. The resulted extracts were further separated by a BEH C18 column,detected by multiple reaction monitoring in electrospray positive ion mode,and quantified by matrix-matched external standard method. The results showed that the recoveries of the target compounds ranged from 70% to 110% at three spiked levels（10,30,and 50 μµg/kg）with the relative standard deviations ranged from 1.4% to 12%. The limits of detection and quantification were 0.57 1.75 and 2.77-5.40 μµg/kg,respectively. This method was suitable for the simultaneous determination of residual macrolides in organic fertilizers. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

Experimental strategy of the spectrophotometric approach using freeze-drying for PO43− determination in frozen and chilled chickens in the Saudi Arabia market

Herein, an efficient analytical method based on an extraction protocol was developed and validated for the spectrophotometric detection of phosphate (PO₄^3?) in chilled and frozen chicken samples. The preparation was a very simple sample that included freeze-drying, extraction with acidified amino acids and filtration of the final extract prior to spectrophotometric analysis. FT-IR spectrum of CS1 was confirmed that the selected solvent has successfully extracted PO₄^3? from the chilled chicken sample. Analytical performances were assessed in chilled of one of the merchant species and showed good recoveries with relative standard deviations (RSD) below 2%. The analytical validation parameters of the method in terms of limit of quantification (LOQ) and detection (LOD) were calculated and found to be 0.10 and 0.032 mg/L, respectively. This protocol has been effectively applied to PO₄^3? determination in chicken samples collected from Saudi supermarkets (Northern KSA), and PO₄^3? in all frozen samples was detected at high mg/kg levels ranging from 2.11 × 10⁴ to 2.90 × 10⁴ mg/kg, while in limit levels of PO₄^3? concentration were detected in the chilled samples except chilled sample 1 (CS1), which was 2.22 × 10⁴ mg/kg. The extraction and determination protocol suggested that this developed method could be validated for routine monitoring of PO₄^3? in food quality control laboratories and safety monitoring.     

Organic pollutants adsorbed on microplastics: Analytical methodologies and occurrence in oceans

The massive use of plastics in several products has generated microplastic debris worldwide. Besides their negative effect on marine organisms by ingestion, microplastics are a contamination vector due to their capacity to transport organic pollutants around our planet. To evaluate the magnitude of this issue, it is necessary to know what kinds of contaminants are adsorbed on microplastics, as well as their concentrations. In order to assess the adsorption and desorption of pollutants from microplastics, effective and reliable extraction procedures are required. In this overview, literature reports, in which extraction, separation and determination methods have been applied to analyse the organic pollutants adsorbed on microplastics, are revised and discussed. Furthermore, the worldwide occurrence of organic compounds found on microplastics in oceans is reviewed and the results obtained from different geographical areas and their global distribution trends are compared. Priority organic pollutants, such as polycyclic aromatic hydrocarbons, hexachlorocyclohexanes, polychlorinated benzenes, perfluoroalkyl substances or bisphenol analogues, have been widely found on microplastic samples. Future research that focuses on different kinds of emerging pollutants is required.     

杂多酸离子液体催化燃油萃取氧化脱硫性能研究

本文首次将一系列含有不同酸性咪唑阳离子和不同杂多酸阴离子的杂多酸离子液体[C4mim]3PW12O40、[COOH-Cmim] 3PW12O40、[SO3H-C3mim]3PW12O40、[SO3H-C3mim]3PMo12O40和[SO3H-C3mim]4 SiW12O40作为催化剂,乙腈为萃取剂,H2O2为氧化剂,用于催化含二苯并噻吩、苯并噻吩及噻吩模型油的萃取氧化脱硫研究中.实验结果显示,杂多酸离子液体催化燃油脱硫性能不仅与阳离子的酸性强弱有关,而且与阴离子结构密切相关.阳离子的催化活性顺序为:[SO3H-C3mim]+＞[COOH-Cmim]+＞[C4mim]+;阴离子的催化活性顺序为PW12O403-＞ PMo12O403-＞ SiW12O404-.其中[SO3H-C3 mim]3 PW12O40催化活性最高,在60℃反应40min的条件下,二苯并噻吩的转化率约为100％,催化不同硫化物的转化率为:二苯并噻吩＞苯并噻吩＞噻吩.此外,该杂多酸离子液体循环使用5次催化活性仅略有下降.     

破乳诱导萃取-电感耦合等离子体质谱法测定柴油中的锰、铁和铅

采用破乳诱导萃取的前处理方法,结合电感耦合等离子体质谱技术(ICP-MS),测定了柴油中的锰、铁和铅元素。首先将样品和表面活性剂溶液(Triton X-114)混合形成稳定的油包水乳液,以硝酸作萃取剂充分萃取柴油中的锰、铁和铅,然后将乳液离心破乳分层,采用ICP-MS内标法测定酸性水相中的锰、铁和铅。3种元素的检出限(3S/N)在0.008~0.083μg·L-1之间,测定下限(10S/N)在0.027~0.28μg·L-1之间。应用该方法对柴油中金属元素进行测定,加标回收率在94.9%~106%之间,相对标准偏差(n=6)在0.66%~2.2%之间。     

Novel test method to estimate bound rubber formation of silica-filled solution styrene-butadiene rubber compounds

Bound rubber formation was investigated in detail by applying various extraction temperatures (at room temperature, 90°C, and 180°C) and novel treatment methods (ammonia bubbling and sonication). Bound rubbers could be divided into three major components of core shell, primary layer including tightly primary layer and occluded rubber, and secondary layer including connecting filament. Bound rubber content of the core shell was measured by four successive procedures of extraction at room temperature, ammonia bubbling, extraction at 180°C and sonication. Bound rubber content of the tightly primary layer was measured by three successive procedures of extraction at 90°C, ammonia bubbling and sonication. Bound rubber content of the primary layer was measured by two successive procedures of extraction at 90°C and sonication.     

Determination of weight distribution ratios of Pa(V) and Np(V) with some extraction chromatography resins and the AG1-X8 resin

Literature data on distribution ratios (D_w) of Np(V) and Pa(V) for the AG1-X8 resin are scarce whereas those related on resin capacity factors (k′) values for TEVA, TRU and U/TEVA resins are absent. Therefore, batch extraction experiments for Pa(V) and Np(V) from HCl and HNO₃ media were realized, at tracer scale, with AG1-X8 and EIChroM resins (TEVA, TRU and U/TEVA). Based on the new D_w and k′ values obtained in this study, a new protocol for Pa/Np separation has been developed leading to a better separation factor of 10⁵ and a chemical yield of 97 ± 3% and 99 ± 1% for Pa and Np, respectively. A separation of ²³¹Pa from uranium matrix was successfully tested.     

Use of Extraction Disks for Trace Enrichment of Various Pesticides from River and Sea Water Samples

Abstract

C-18 Empore extraction disks were used for the isolation and trace enrichment of different groups of pesticides from river water and artificial sea water at concentration levels of 0.2, 5 and 20 μg/l [chlorotriazines, (atrazine and simazine), their dealkylated metabolites, (deethyl- and deisopropylatrazine), organophosphorus (parathion-ethyl), phenylurea (linuron), anilide (propanil), carbamate (aldicarb and carbofuran) and carbamate transformation products (aldicarb sulfoxide, aldicarb sulfone and 3-hydroxy-7-phenol carbofuran]. The extraction disks allowed high flow rates thus 51 samples could be processed within 2h. 30 min.

For most of the pesticides the recoveries, as determined by liquid chromatography with diode array detection (LC-DAD), varied from 74 up to 125% with coefficients of variations (CV) of 5-10%, whereas for the carbamate transformation products the recoveries were in the range of 30-35% having a CV of 17-21%. At spiking level of 0.2 μg/l the dealkylated triazine metabolites and the carbamate transformation products were not detected at all.     

Some Correlations Between Chelate Extraction Distribution Ratios,Bond Types,and Solvent Physical Properties

Abstract

Correlations between extraction distribution ratios, bond types, and common solvent physical properties were determined for 19 extraction systems. Different types of bonding are involved in the water adduct formation on different types of chelates.