Development and Validation of a High-Performance Liquid Chromatography-Tandem Mass Spectrometry Method to Determine Promethazine and Its Metabolites in Edible Tissues of Swine.

This study aimed to determine promethazine (PMZ) and its metabolites, promethazine sulfoxide (PMZSO) and monodesmethyl-promethazine (Nor1PMZ), in swine muscle, liver, kidney, and fat. A sample preparation method and high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis were established and validated. The samples were extracted using 0.1% formic acid-acetonitrile and purified with acetonitrile-saturated n-hexane. After concentration by rotary evaporation, the extract was re-dissolved in a mixture of 0.1% formic acid-water and acetonitrile (80:20, v/v). Analysis was performed using a Waters Symmetry C18 column (100 mm × 2.1 mm i.d., 3.5 µm) with 0.1% formic acid-water and acetonitrile as the mobile phase. The target compounds were determined using positive ion scan and multiple reaction monitoring. PMZ and Nor1PMZ were quantified with deuterated promethazine (PMZ-d6) as the internal standard, while PMZSO was quantified using the external standard method. In spiked muscle, liver, and kidney samples, the limits of detection (LOD) and limits of quantification (LOQ) for PMZ and PMZSO were 0.05 µg/kg and 0.1 µg/kg, respectively, while for Nor1PMZ, these values were 0.1 µg/kg and 0.5 µg/kg, respectively. For spiked fat samples, the LOD and LOQ for all three analytes were found to be 0.05 µg/kg and 0.1 µg/kg, respectively. The sensitivity of this proposed method reaches or exceeds that presented in previous reports. The analytes PMZ and PMZSO exhibited good linearity within the range of 0.1 µg/kg to 50 µg/kg, while Nor1PMZ showed good linearity within the range of 0.5 µg/kg to 50 µg/kg, with correlation coefficients (r) greater than 0.99. The average recoveries of the target analytes in the samples varied from 77% to 111%, with the precision fluctuating between 1.8% and 11%. This study developed, for the first time, an HPLC-MS/MS method for the determination of PMZ, PMZSO, and Nor1PMZ in four swine edible tissues, comprehensively covering the target tissues of monitoring object. The method is applicable for monitoring veterinary drug residues in animal-derived foods, ensuring food safety.

Correction: Adsorption of polycyclic aromatic hydrocarbons over CuZnFeAl-LDH modified by sodium dodecyl sulfate.

[This corrects the article DOI: 10.1039/D2RA03968K.].

Adsorption of polycyclic aromatic hydrocarbons over CuZnFeAl-LDH modified by sodium dodecyl sulfate.

Polycyclic aromatic hydrocarbons (PAHs) have received extensive attention due to being highly toxic, mutagenic, and carcinogenic organic pollutants. As a result, a series of adsorbents have been designed and developed to solve the problem. In this paper, CuZnFeAl-S has been explored as a highly efficient adsorbent for PAHs. First, CuZnFeAl-LDH was prepared using a coprecipitation method and then calcined at 500 °C to obtain CuZnFeAlO. Finally, CuZnFeAl-S was prepared by modifying CuZnFeAlO with sodium dodecyl sulfate (SDS). The physical and chemical properties of the adsorbents were characterized by XRD, N2 adsorption-desorption, SEM, ICP, FT-IR, TG-DSC, and IGC; subsequently their adsorption performance was investigated. The results show that the surface properties of CuZnFeAl-S changed from hydrophilic to hydrophobic after SDS modification, which enhanced the adsorption of PAHs obviously. The removal of naphthalene and phenanthrene on CuZnFeAl-S reached 97.3% and 90.3%, respectively. And the adsorption process of naphthalene and phenanthrene conforms to Langmuir adsorption and Freundlich adsorption, respectively. Besides, the adsorption thermodynamics indicate that the adsorption of PAHs was a spontaneous exothermic reaction. The highly efficient PAH adsorption performance of CuZnFeAl-S is the synergistic result of various molecule interactions, such as hydrogen bonding, π-π interactions, and electrostatic attraction.

Theoretical Studies on the Oligomerization of Silicate Species in Basic Solution.

The possible reaction pathways of silicate species to linear- and ring-structure oligomers up to silicate hexamers in the basic medium have been studied using the density functional theory. The calculations were performed at the ωB97XD/6-31+G(d,p) level, and the integral equation formalism polarizable continuum model was employed to simulate the solvent effects, and it was found that they are appropriate in exploring the reaction mechanism of silicate species condensation. There are two steps in the anionic silicate condensation reactions: the SiO-Si bond formation step and the dehydration step. Moreover, the latter is the rate-limiting step for most of the reaction pathways except for the cyclization reaction of the linear pentamer to the 5-ring. The short linear oligomers would be likely formed from the reaction between monomers and oligomers, while the longer ones are easily formed through the reactions between short oligomers. The 4-ring and branched 5-ring oligomers are found to be formed very favorable both in kinetic and thermodynamic and could have great influences on the initial stage of zeolite synthesis. The intramolecular and intermolecular hydrogen bond effect of silicate species is an important factor affecting the reaction mechanism.

A REPORT OF RADIATION RISKS DURING AND AFTER PROCESSING MINERAL PLACER FROM SOUTHEAST AFRICA.

Recently, high levels of radioactivity were found in products from Chinese mineral processing industries that handle mineral placer from Southeast Africa. The findings led to public panic. The aim of this work is to provide radiological data for the government, workers and the public. In this work, activity concentrations of 238U,232Th,226Ra and40 K in raw ore from Southeast Africa were analysed in the laboratory. Products like monazite and building material were analysed. High concentrations of 238U,232 Th and 226Ra in products were found to be at a level of 104  Bq/kg. Around the South China Mineral Processing Industry, radioactivity in soil and groundwater was analysed. Absorbed dose rates in air and indoor radon concentrations at workplaces were monitored. Annual effective dose to workers and the public was calculated and found to exceed Chinese dose criterion. This report might be an alert for mining and mineral processing in Southeast Africa.

[Effects of Moxibustion at "Feishu"(BL 13) and "Shenshu"(BL 23) on Peripheral Blood T Cells and Serum Interleukin in Asthmatic Rats].

OBJECTIVE: To observe the effect of moxibustion at "Feishu" (BL 13) and "Shenshu"(BL 23) on peripheral blood T cells and serum interleukin in rats with asthma, so as to explore its immunological mechanisms in relieving asthma. METHODS: Thirty SD rats were randomly divided into normal, model and moxibustion groups(10 rats/group). Asthma model was established by intraperitoneal injection of ovalbumin and aluminum hydroxide, and ovalbumin inhalation. Moxibustion was applied to bilateral "Feishu" (BL 13) and "Shenshu"(BL 23) for 30 min, once daily for 14 d. The pathologic changes of the lung tissue were detected by H.E. staining. The levels of CD 3+, CD 4+, CD 8+ T cells in whole blood were detected by flow cytometry. Serum IgE, IL-1 ß, IL-1 Ra contents were assayed by ELISA (enzyme-linked immunosorbent assay). RESULTS: The thickened muscle of bronchial wall, mucosal edema, infiltration of inflammatory cells and partial destruction of the alveolar structure were found in the model group. While in the moxibustion group, the structure of the alveolar wall was complete, the morphology of the bronchioles was regular, and there were no mucus plug formation and epithelial cell shedding in the lumen. The contents of blood CD 8+ and CD 3+ T cells, and serum IgE and IL-1 ß in the model group were obviously higher than those in the normal group (P<0.01). Compared with the model group, the levels of blood CD 8+ T cell, serum IgE and IL-1 ß in the moxibustion group were all decreased (P<0.05,P<0.01), meanwhile the levels of blood CD 4+ T cell and serum IL-1 Ra were increased (P<0.01,P<0.05). CONCLUSIONS: Moxibustion can reduce the levels of serum IgE and IL-1 ß, and increase the level of serum IL-1 Ra, which may play an important role in the treatment of asthma.

Simultaneous desulfurization and denitrification by microwave reactor with ammonium bicarbonate and zeolite.

Microwave reactor with ammonium bicarbonate (NH(4)HCO(3)) and zeolite was set up to study the simultaneous removal of sulfur dioxide (SO(2)) and nitrogen oxides (NO(x)) from flue gas. The results showed that the microwave reactor filled with NH(4)HCO(3) and zeolite could reduce SO(2) to sulfur with the best desulfurization efficiency of 99.1% and reduce NO(x) to nitrogen with the best NO(x) purifying efficiency of 86.5%. Microwave desulfurization and denitrification effect of the experiment using ammonium bicarbonate and zeolite together is much higher than that using ammonium bicarbonate or zeolite only. NO(x) concentration has little effect on denitrification but has no influence on desulfurization, SO(2) concentration has no effect on denitrification. The optimal microwave power and empty bed residence time (EBRT) on simultaneous desulfurization and dentrification are 211-280 W and 0.315 s, respectively. The mechanism for microwave reduced desulfurization and denitrification can be described as the microwave-induced catalytic reduction reaction between SO(2), NO(x) and ammonium bicarbonate with zeolite being the catalyst and microwave absorbent.