Simultaneous analysis of ten phytohormones in Sargassum horneri by high‐performance liquid chromatography with electrospray ionization tandem mass spectrometry

Phytohormones have attracted wide attention due to their important biological functions. However, their detection is still a challenge because of their complex composition, low abundance and diverse sources. In this study, a novel method of high‐performance liquid chromatography with electrospray ionization tandem mass spectrometry was developed and validated for the simultaneous determination of ten phytohormones including indole‐3‐acetic acid, isopentenyladenine, isopentenyl adenosine, trans‐zeatin riboside, zeatin, strigolactones, abscisic acid, salicylic acid, gibberellin A3, and jasmonic acid in Sargassum horneri (S. horneri). The phytohormones were extracted from freeze‐dried S. horneri with methanol/water/methanoic acid (15:4:1, v/v/v) analyzed on a Hypersil Gold C₁₈ column and detected by electrospray ionization tandem triple quadrupole mass spectrometry in the multiple reaction monitoring mode. The experimental conditions for the extraction and analysis of phytohormones were optimized and validated in terms of reproducibility, linearity, sensitivity, recovery, accuracy, and stability. Distributions of the phytohormones in the stems, blades, and gas bladder of the S. horneri in drift, fixed, and semi‐fixed growing states were investigated for the first time. The observed contents of the phytohormones in S. horneri range from not detected to 5066.67 ng/g (fresh weight). Most phytohormones are distributed mainly in the stems of S. horneri in drift and semi‐fixed states.     

Identification of chemical constituents in traditional Chinese medicine formula using HPLC coupled with linear ion trap‐Orbitrap MS from high doses of medicinal materials to equivalent doses of formula: Study on Xiang‐Sha‐Liu‐Jun‐Zi‐Jia‐Jian granules

High‐resolution mass spectrometry has been a powerful tool for the research of chemical constituents in traditional Chinese medicine (TCM) formulas. However, the chromatographic peaks were difficult to discriminate clearly in data collection or analysis because of the complexity and the greatly different content of the constituents in TCM formula, which increased the difficulty of identification. In this study, a high‐performance liquid chromatography coupled with linear ion trap‐Orbitrap mass spectrometry based strategy focused on the comprehensive identification of TCM formula constituents was developed. Identification was carried out from a high dose of medicinal materials to equivalent dose of formula. Meanwhile, combined with mass spectrometry data, chromatographic behaviors, reference standards and previous reports, the identification of constituents in Xiang‐Sha‐Liu‐Jun‐Zi‐Jia‐Jian granules was described. 169 compounds were unambiguously or tentatively characterized, mainly including flavonoids, alkaloids, triterpenic acids, triterpene saponins, lactones, sesquiterpenoids and some other compounds. Among them, 11 compounds were unambiguously confirmed by comparing with reference standards. These results demonstrated that the method was effective and reliable for comprehensive identification of constituents of Xiang‐Sha‐Liu‐Jun‐Zi‐Jia‐Jian granules extracts and reveal the material basis of its therapeutic effects. This strategy might propose a research idea for the characterization of multi‐constituents in TCM formula.     

Extraction of quinolones from milk samples using bentonite/magnetite nanoparticles before determination by high‐performance liquid chromatography with fluorimetric detection

In this work, bentonite magnetic nanoparticles synthesized by a typical coprecipitation method were used as the adsorbent for the magnetic solid‐phase extraction of six quinolones (ciprofloxacin, difloxacin, enrofloxacin, norfloxacin, sarafloxacin, and lomefloxacin) from milk samples followed by high‐performance liquid chromatography with fluorimetric detection. Under the optimized conditions, the linear quantitation range for the six quinolones was 0.3–200 ng/mL, and the correlation coefficients of the calibration curves ranged from 0.9994 to 0.9999. The detection limit of the method was 0.1 ng/mL. Recoveries of quinolones from pure and low‐fat spiked milk samples varied from 80.4 to 92.7% and from 81.3 to 93.5%, respectively. These results demonstrated that the proposed method for the determination of six quinolones in milk samples was rapid, reliable, and efficient.     

Pipette vial dispersive liquid–liquid microextraction combined with high‐performance liquid chromatography for the determination of benzoylurea insecticide in fruit juice

A simple, sensitive, and efficient method of using a pipette vial to perform dispersive liquid–liquid microextraction based on the solidification of floating organic droplets was coupled with high‐performance liquid chromatography (HPLC) and a diode array detector for the preconcentration and analysis of four benzoylurea insecticides in fruit juice. In this method, 1‐dodecanol was used as an extractant, and a snipped pipette was used as an experimental vial to simplify the procedure of collecting and separating solidified extractant. The experimental parameters were optimized using a Plackett–Burman design and one‐factor‐at‐a‐time method. Under the optimal conditions in the water model, the limits of detection for analytes varied from 0.03 to 0.28 μg/L, and the enrichment factors ranged from 147 to 206. Linearity was achieved for diflubenzuron and flufenoxuron in a range of 0.5–500 μg/L, for hexaflumuron in a range of 1–500 μg/L, and for triflumuron in a range of 5–500 μg/L. The correlation coefficients for the analytes ranged from 0.9986 to 0.9994 with recoveries of 91.4–110.9%. Finally, the developed technique was successfully applied to fruit juice samples with acceptable results. The relative standard deviations of the analytes at two spiking levels (50 and 200 μg/L) varied between 0.2 and 4.5%.     

Computational design and fabrication of core–shell magnetic molecularly imprinted polymer for dispersive micro‐solid‐phase extraction coupled with high‐performance liquid chromatography for the determination of rhodamine 6G

A novel core–shell magnetic nano‐adsorbent with surface molecularly imprinted polymer coating was fabricated and then applied to dispersive micro‐solid‐phase extraction followed by determination of rhodamine 6G using high‐performance liquid chromatography. The molecularly imprinted polymer coating was prepared by copolymerization of dopamine and m‐aminophenylboronic acid (functional monomers), in the presence of rhodamine 6G (template). The selection of the suitable functional monomers was based on the interaction between different monomers and the template using the density functional theory. The ratios of the monomers to template were further optimized by an OA₉ (3⁴) orthogonal array design. The binding performances of the adsorbent were evaluated by static, kinetic, and selective adsorption experiments. The results reveal that the adsorbent possesses remarkable affinity and binding specificity for rhodamine 6G because of the enhanced Lewis acid‐base interaction between the B(Ш) embedded in the imprinted cavities and the template. The nano‐adsorbent was successfully applied to dispersive micro‐solid‐phase extraction coupled to high‐performance liquid chromatography for the trace determination of rhodamine 6G in samples with a detection limit of 2.7 nmol/L. Spiked recoveries ranged from 93.0–99.1, 89.5–92.7, and 86.9–105% in river water, matrimony vine and paprika samples, respectively, with relative standard deviations of less than 4.3%.     

雷公藤内酯醇和缬沙坦对高糖诱导小鼠足细胞活性的影响

目的观察不同浓度高糖对小鼠足细胞活性的抑制作用,以及不同浓度雷公藤内酯醇（TP）和缬沙坦（Val）对高糖抑制后小鼠足细胞活性的影响,探讨高糖对足细胞的损伤作用,以及有效的药物干预浓度范围。方法将培养成熟的小鼠足细胞随机分为对照组（11.1mmol/L葡萄糖）和不同浓度高糖组（16.1、21.1、26.1、31.1、36.1mmol/L）,以上述浓度培养48h后采用CCK-8检测足细胞活性的变化。取活性变化最大的浓度为高糖诱导浓度,在此基础上随机分为不同浓度的TP组（4、8、16、32、64ng/ml）和Val组（2×10-8、2×10-7、2×10-6、2×10-5、2×10-4mol/L）,以上述浓度干预48h后,采用CCK-8检测足细胞活性的变化。结果（1）与对照组相比,除16.1mmol/L高糖组外,其余各高糖组的足细胞活性显著减少,其中以26.1mmol/L葡萄糖组减少最为明显（P＜0.01）。（2）与26.1mmol/L葡萄糖组相比,TP组（除4ng/ml组外）和Val组（除2×10-8mol/L组外）足细胞活性部分恢复,其中以16ng/mlTP组和2×10-5mol/LVal组足细胞活性恢复最为明显（P＜0.01）。结论一定浓度范围的TP和Val可部分恢复受高糖抑制的小鼠足细胞活性。     

直接竞争酶联免疫吸附法测定饲料中沙丁胺醇

应用本实验室制备的对沙丁胺醇(SAL)具有高亲和力的多克隆抗体和酶标半抗原,采用包被抗体-酶标半抗原直接竞争模式建立沙丁胺醇的酶联免疫吸附分析(ELISA)法。在优化实验条件下,ELISA法检测沙丁胺醇的线性浓度范围为0.1~1.0×10~3μg/L,沙丁胺醇对抗体-酶标半抗原结合反应的抑制中浓度(Ic50)为14μg/L,相对标准偏差(RSD)为8.6%(n=5),定量检测下限(Ic_(10))为0.29μg/L。在猪饲料中分别添加沙丁胺醇标样10、50、250μg/kg,ELISA法检测的回收率分别为85%~108%、81%~92%和81%~102%,RSD(n=5)分别为9.1%、5.6%和8.9%,对饲料中沙丁胺醇的最低定量检测浓度为4.23μg/kg。利用高效液相色谱-紫外检测(HPLC-UV)法同步测定饲料中添加250μg/kg沙丁胺醇的平均回收率为89%(n=3),相对标准偏差为3.9%。     

高效液相色谱-串联质谱法同时检测水中17种抗生素

建立了高效液相色谱-串联质谱(HPLC-MS/MS)同时检测水中大环内酯类、磺胺类、甲氧苄啶、四环素类、氟喹诺酮类五类共17种抗生素含量的分析方法。水样经Oasis HLB固相萃取小柱富集净化后,以CORTECSTM C18色谱柱(100×4.6mm,2.7μm)分离,2%甲酸+2mmol/L乙酸铵溶液-乙腈为流动相,在电喷雾离子源正离子模式下采用质谱多反应监测模式(MRM)检测。结果表明,各目标化合物在0.50~250ng/mL范围内,线性关系良好(R20.990),检测限为0.01~2.50ng/L;在10和100ng/L添加水平下,17种抗生素的加标回收率为60.6%~125%,相对标准偏差(RSDs,n=4)为0.311%~14.8%。应用该方法测定广州市某河流的水样,除三乙酸竹桃霉素、氯四环素、洛美沙星、恩氟沙星上游未被检出,下游微量检出外,其余13种抗生素均有检出,其中氧四环素的浓度最高,最大值达560ng/L,四环素次之,为540ng/L。     

高浓度体系制备ZSM-5分子筛及碱处理后甲醇制丙烯性能

在高浓度体系下,以粗孔硅胶和偏铝酸钠为原料,TPABr为模板剂,水热晶化法制备了ZSM-5分子筛,单釜产率23％.用不同浓度的氢氧化钠溶液对ZSM-5分子筛进行改性,采用XRD、FT-IR、SEM、NH3-TPD、XRF、N2物理吸附等方法对改性前后的样品进行了表征,并考察了改性后ZSM-5分子筛甲醇催化转化制丙烯(MTP)反应性能.结果表明,氢氧化钠改性未破坏分子筛的骨架结构,改性后样品的酸量、介孔孔容和BET比表面积均有增加,从而改善了催化剂的抗积碳性能和反应性能.在MTP反应中,增产丙烯的效果不明显,但表现出了更好的催化稳定性(催化剂使用寿命从85 h提升至110 h),并且有利于提高副产物汽油组分(∑C5+)的产量.     

Separation of three anthraquinone glycosides including two isomers by preparative high‐performance liquid chromatography and high‐speed countercurrent chromatography from Rheum tanguticum Maxim. ex Balf

Anthraquinone glycosides, such as chrysophanol 1‐O‐β‐d‐ glucoside, chrysophanol 8‐O‐β‐d‐ glucoside, and physion 8‐O‐β‐d‐ glucoside, are the accepted important active components of Rheum tanguticum Maxim. ex Balf. due to their pharmacological properties: antifungal, antimicrobial, cytotoxic, and antioxidant activities. However, an effective method for the separation of the above‐mentioned anthraquinone glycosides from this herb is not currently available. Especially, greater difficulty existed in the separation of the two isomers chrysophanol 1‐O‐β‐d‐ glucoside and chrysophanol 8‐O‐β‐d‐ glucoside. This study demonstrated an efficient strategy based on preparative high‐performance liquid chromatography and high‐speed countercurrent chromatography for the separation of the above‐mentioned anthraquinone glycosides from Rheum tanguticum Maxim.ex Balf.