Preparative chromatography behavior of palmitoleic acid on octadecyl stationary phases with different densities

The availability of various high-purity unsaturated fatty acids has a wide range of needs due to their different activities. The nonlinear preparative chromatography behavior and principle for purification of palmitoleic acid with octadecyl bonded stationary phases were studied. The peak broadening and the concentration distribution of the target compounds were used to compare different C18 stationary phases. In preparative liquid chromatography, the C18 stationary phases with low, medium, and high bonding density showed different peak broadening and concentration distribution results. Medium bonding density C18 was suitable for the purification of ethyl palmitoleic acid. The forward broadening was much greater than the backward broadening on medium bonding density C18 column. And the highest concentration distribution of impurities and the main peak was not crossed in this column. Due to the low content of crude ethyl palmitoleic acid sample, a two-step purified method yields an oily product with purity of 96.57% in the GC method. This method would be universal and extensible for constructing purification method for other unsaturated fatty acids.     

石柱黄连及根际土壤中矿质元素特征分析

研究石柱黄连不同器官及其根际土壤中矿质元素特征,探究黄连根茎矿质元素间及其与土壤环境的相关性。采用电感耦合等离子体质谱法(ICP-MS)、电感耦合等离子体发射光谱法(ICP-OES)及原子荧光光谱法(AFS)测定了15组石柱黄连植株和根际土壤中18种矿质元素含量,所得数据运用SPSS 22.0统计软件分析。石柱黄连根际土壤中锰、磷、镁、镉、汞等元素含量的变异性较大,部分采样点土壤中镉含量超过农用地土壤污染风险筛选值。在检测的18种元素中,黄连植株中钙、镁、磷、钾含量最高,其次是铁、锰、锌,再次是锶、铜、镍,最后是铅、钒、钴、镉、钼、铬、砷、汞。须根对大部分矿质元素的富集能力强于根茎或地上部;黄连根茎对锌的富集能力强于须根或地上部;地上部对钙、磷、钾、铬的富集能力强于须根或根茎。Spearman分析表明黄连根茎矿质元素间、黄连根茎与土壤中矿质元素有一定相关性,部分具有统计学意义(P＜0.05)。石柱黄连不同器官中矿质元素含量有明显差异,以此建立的指纹图谱可用于区分黄连根茎及须根的粉末样品;黄连根茎中矿质元素间主要表现为协同作用,黄连根茎与土壤中矿质元素既有协同作用又有拮抗作用。     

Effects and Economic Sustainability of Biochar Application on Corn Production in a Mediterranean Climate

The effects of two types of biochar on corn production in the Mediterranean climate during the growing season were analyzed. The two types of biochar were obtained from pyrolysis of Pinus pinaster. B1 was fully pyrolyzed with 55.90% organic carbon, and B2 was medium pyrolyzed with 23.50% organic carbon. B1 and B2 were supplemented in the soil of 20 plots (1 m²) at a dose of 4 kg/m². C1 and C2 (10 plots each) served as control plots. The plots were automatically irrigated and fertilizer was not applied. The B1-supplemented plots exhibited a significant 84.58% increase in dry corn production per square meter and a 93.16% increase in corn wet weight (p << 0.001). Corn production was no different between B2-supplemented, C1, and C2 plots (p > 0.01). The weight of cobs from B1-supplemented plots was 62.3%, which was significantly higher than that of cobs from C1 and C2 plots (p < 0.01). The grain weight increased significantly by 23% in B1-supplemented plots (p < 0.01) and there were no differences between B2-supplemented, C1, and C2 plots. At the end of the treatment, the soil of the B1-supplemented plots exhibited increased levels of sulfate, nitrate, magnesium, conductivity, and saturation percentage. Based on these results, the economic sustainability of this application in agriculture was studied at a standard price of €190 per ton of biochar. Amortization of this investment can be achieved in 5.52 years according to this cost. Considering the fertilizer cost savings of 50% and the water cost savings of 25%, the amortization can be achieved in 4.15 years. If the price of biochar could be reduced through the CO₂ emission market at €30 per ton of non-emitted CO₂, the amortization can be achieved in 2.80 years. Biochar markedly improves corn production in the Mediterranean climate. However, the amortization time must be further reduced, and enhanced production must be guaranteed over the years with long term field trials so that the product is marketable or other high value-added crops must be identified.     

水为载流-原子荧光光谱法同时测定土壤中痕量砷、汞

改变原子荧光光谱法以稀酸为载流的进样方式,以水为载流在新型双道原子荧光光谱仪上同时测定了土壤中的痕量砷(As)、汞(Hg)。方法采用王水水浴加热溶解样品,用50 g/L硫脲-抗坏血酸混合溶液预先将砷还原为+3价,保持10%(体积分数)以上盐酸浓度,不转移直接定容静置后测定。优化了仪器工作条件,详细考察了以水为载流测定的可行性,选择了同时测定As、Hg所需的硼氢化钾浓度和盐酸浓度。方法节省了酸试剂用量,操作快速,单个样品测定仅需20s左右。方法检出限As为0.005 mg/kg,Hg为0.0008 mg/kg,相对标准偏差(RSD%,n=7)在1.0%～7.4%,经土壤国家标准物质和实际样品验证,适合土壤中痕量As、Hg的同时快速测定。     

土壤微塑料污染及生态环境效应研究进展

微塑料作为一种新的污染物,具有粒径小、疏水性强、性质稳定、可以吸附多种污染物等特点,近年来受到了广泛的关注。目前关于微塑料的研究主要集中在水环境中,土壤环境中的微塑料研究相对滞后。土壤与人类生活息息相关,但土壤微塑料污染的现状却不容乐观,土壤微塑料的环境效应需要重视。本文综述了土壤微塑料的来源、分离和鉴定方法、微塑料在土壤环境中的行为和生态效应,并对土壤微塑料的研究前景进行了展望。     

光催化降解土壤中多环芳烃

多环芳烃(PAHs)是一类广泛分布于土壤中的持久性有机污染物,其化学结构稳定,具有高疏水性、难降解性和三致毒性,多产生于交通运输、工业生产、垃圾焚烧等人为活动中。近年来,日益严峻的PAHs污染给土壤生态、食品安全和民众健康带来严重威胁。因此,对土壤PAHs污染的治理具有重要意义且亟待解决。在众多PAHs处理技术中,光催化技术凭借能耗低、操作简便、环境友好等优势,受到了研究者们的广泛关注。本文概述了PAHs的光催化降解机理与途径,综述了光催化修复土壤PAHs领域的研究进展,讨论了不同环境因素对催化剂降解效果的影响,并总结了当前光催化技术应用于土壤PAHs污染修复所面临的挑战。     

Dimethyl sulfoxide/oxalyl chloride: A useful reagent for sulfenyletherification

A facile method for the sulfenyletherification of unsaturated alcohols using dimethyl sulfoxide/oxalyl chloride has been described in this article. Methanesulfenyl chloride is supposed to be the compound responsible for the sulfenyletherification, which is generated by the reaction of oxalyl chloride with 2 equivalents of dimethyl sulfoxide. The formation pathway of methanesulfenyl chloride is discussed based on the formation of cyclic acetals.     

Amberlyst 15–Catalyzed Efficient Synthesis of 2,3‐Unsaturated Glycosides via Ferrier Rearrangement for Glycal

Amberlyst 15 serves as an inexpensive, effective, and environmentally friendly catalyst in converting 3,4,6‐tri‐O‐acetyl‐D‐glucal (1) into 2,3‐unsaturated O‐ and S‐glycosides via Ferrier rearrangement in moderate to excellent yields with high α selectivity.     

土壤样品中低浓度滴滴涕分析方法的前处理研究

为准确灵敏地分析土壤中低浓度滴滴涕及其衍生物（DDTs）,以正己烷-丙酮（1:1,体积比）作为提取剂超声提取土壤中的DDTs,采用自主研发的四通道色谱分离仪对提取液进行分离,利用装有电子捕获检测器的气相色谱（GC/ECD）进行分析,探讨了不同层析柱填料和洗脱剂对6种DDTs目标物回收率的影响。结果表明,采用新型混合层析柱填料,以二氯甲烷-正己烷（4:1）作为洗脱剂,各目标物的超声提取回收率为83.5%⁹0.3%,方法的检出限为2.0⁵.4 ng·g^-1。并对超声提取和索氏提取法的加标回收率进行了比较。     

土壤无机元素与中药品质关系研究进展

综述了近几年土壤无机元素与中药品质关系的最新研究进展,主要包括土壤无机元素影响中药品质的机制研究、土壤无机元素影响中药化学成分的研究、土壤无机元素与中药道地性关系的研究,以及土壤无机元素与中药毒性关系的研究,并指出了目前研究中存在的主要问题和今后研究的主要方向。