Synthesis of magnetic framework composites for the discrimination of Escherichia coli at the strain level

Rapid and efficient characterization and identification of pathogens at the strain level is of key importance for epidemiologic investigations, which still remains a challenge. In this work, solvothermically Fe₃O₄-COOH@MIL-101 composites were fabricated by in situ crystallization approach. The composites combine the excellent properties of both chromium (III) terephthalate (MIL-101) and carboxylic-functionalized magnetite (Fe₃O₄-COOH) particles and possess the efficient peptides/proteins enrichment properties and magnetic responsiveness. Fe₃O₄-COOH@MIL-101 composites as magnetic solid phase extraction materials were used to increase the discriminatory power of MALDI-TOF MS profiles. BSA tryptic peptides at a low concentration of 0.25 fmol μL⁻¹ could be detected by MALDI-TOF MS. In addition, Fe₃O₄-COOH@MIL-101 composites were successfully applied in the selective enrichment of the protein biomarkers from bacterial cell lysates and discrimination of Escherichia coli at the strain level. This work provides the possibility for wide applications of magnetic MOFs to discriminate pathogens below the species level.     

水溶性硼酸亲和富集材料的制备及基于酶联免疫吸附法检测人肝微粒体糖蛋白的应用

生物样品中的糖蛋白丰度低,且在检测中易受到其它非糖蛋白的抑制和干扰,需在分析检测前对糖蛋白进行富集,但常规的基于固相材料的糖蛋白富集方法不易与生物技术中最经典的酶联免疫吸附法(ELISA)兼容.本研究以树枝状聚合物PAMAM 4.0为载体, 结合硼酸亲和技术,制备了新型水溶性硼酸亲和富集材料(DBC),并将其应用于基于ELISA的人肝微粒体中糖蛋白的检测.采用标准糖蛋白对DBC富集条件进行优化,然后考察其灵敏度和抗干扰能力,将优化后的方法应用于复杂样品人肝微粒体糖蛋白富集.结果表明,DBC对糖蛋白的富集选择性可高达100000倍,可将糖蛋白的富集信号提高100倍.以DBC为富集材料,与ELISA分析技术相结合,只需一步简单的孵育,即可实现生物样品中糖蛋白的高灵敏度、高选择性检测,为疾病相关的糖蛋白组学研究提供了一种有效的检测手段.     

Enrichment of phenols from water with in-situ derivatization by in-tube solid phase microextraction-solvent desorption prior to off-line gas chromatographic determination with large-volume injection

Sorption of phenols from water into the stationary phase of open tubular columns (named in-tube solid phase microextraction) as an enrichment method for gas chromatographic (GC) analysis of aqueous samples was studied. The effect of operating conditions (stationary phase polarity, swelling of the stationary phase by solvents, number of sampling cycles, salting-out effect, sampling velocity, flow rate of desorption solvent) on the process efficiency was evaluated. Real water samples were also used in this study. Swelling of the stationary phase by organic solvent enables the volume of the stationary phase to be increased and its properties to be modified. The use of toluene or tetrachloromethane for the purpose results in high extraction efficiencies for most phenols. The results demonstrated a direct relationship between the extracted amount of phenols and its initial concentration in the sample. The limit of detection in off-line analyses applying large-volume injection was lower than 0.04 μg L⁻¹.These results of the use of in-tube solid phase microextraction with solvent desorption as a non-exhaustive (equilibrium sorptive) enrichment method show a great potential for on-line chromatographic analysis of micropollutants in real water samples.     

甜瓜各器官6种重金属富集及转运能力 差异的比较分析

为比较6种重金属元素在甜瓜植株各器官中富集及转运能力的差异,于果实成熟期采集土壤、根、茎、叶、果实并测定其中的Cr、Cu、As、Ni、Pb和Cd 6种重金属元素,在此基础上,通过富集系数、转运系数,评估了植株不同器官中重金属元素富集能力的差异,比较了各迁移阶段6种重金属元素转运能力的差异。结果显示,各器官中,根富集重金属元素的能力最强,较其他受试重金属元素,Cd和Cu更易在甜瓜植株中富集;迁移各阶段中,Cr、Ni、As、Pb 4种重金属元素由茎转运至果实和叶片的能力相对较强,Cd由根转运至茎的转运能力更强;重金属元素Cu由茎转运至叶片的能力相对较弱。不同重金属元素在甜瓜植株各器官中的富集、转运能力有所差异,宜根据目标调控重金属元素种类,开展对应主要转运阶段阻滞技术的研究与探讨。     

泡沫塑料富集火焰原子吸收光谱法测定有色金属矿物中低品位伴生金含量

近年来,我国的金矿资源不断减少,矿石逐渐趋向于“贫、细、杂”。随着现代选矿技术在不断向前发展,加强对低品位伴生金资源的有效开采和利用,在矿业界中逐渐引起重视。在当前我国经济技术支撑下,选矿行业对这方面做了大量的工作,使低品位伴生金的回收利用方面取得了很大的进步。本文以云南锡业某矿区有色金属矿物中低品位伴生金含量进行金的检测分析,通过对矿石矿物结构性质的了解,以及金的检测方法比对,选用分析操作快捷、经济、安全、环保,结果有保障的泡沫塑料富集火焰原子吸收光谱法,经2个国家标准物质验证,并抽取当地6个代表性样品分析结果精密度和准确度进行考察,RSD(n=11)均小于20%,样品加标回收率在95.2～109%,达到了对金含量的检测目的。     

壳聚糖富集分离原子荧光光谱法测定环境水样中无机锡

研究了壳聚糖对无机锡的富集洗脱行为,并对富集的机理进行了探讨。提出了壳聚糖富集分离氢化物发生-原子荧光光谱法测定环境水样中无机锡的方法。研究了富集分离的最佳条件,在pH 4时,壳聚糖对Sn(Ⅱ)和Sn(Ⅳ)的富集率分别为96%和99%以上,用1%~30%(体积分数)的硫酸即可定量洗脱,同时考察了共存元素的影响,方法的检出限为4.5 ng.L-1,回收率在93%以上,相对标准偏差为4.5%。     

活性炭动态富集-火焰原子吸收光谱法测定金矿石中金的影响因素探讨

金在新一轮找矿突破战略行动矿产分析中占有重要的地位,采用活性炭动态富集-火焰原子吸收光谱法测定岩石矿物样品中金的分析方法已被广泛应用。然而其分析条件的影响因素较多,在测定过程中活性炭的用量、灰分的大小、吸附层的设计以及洗涤液溶液温度等因素对测定结果的准确性具有重要影响。试验分别以活性炭用量、不同灰分值、吸附层数以及洗涤溶液的温度为变量,对金分析标准物质GBW(E)070013b、GBW07297a、GBW07299a、GBW07810进行实验对比分析。结果表明,金的回收率随着活性炭用量的增加而不断提升,在0.5g后趋于稳定;活性炭灰分值越大,金元素损失越多,当灰分值小于0.05%时,回收率趋于稳定,接近99%;活性炭吸附层设计为双层和三层时,测定值的平均值与认定值的相对偏差(RE/%)和相对标准偏差(RSD/%,ｎ=6)分别为0.14%～3.22%和0.04%～3.68%,优于混合层和单层,满足岩石矿物质控标准规范中正确度和精密度的要求;抽滤洗涤热溶液(70℃～80℃)时,金矿石标准物质金元素的平行样的准确度和相对标准标准偏差最小,均小于2.1%,通过方法验证,测定金的正确度精密度(RSD,n=6)分别小于0.76%和3.78%,满足DZ/T 0130.3-2006《地质矿产实验室测试质量管理规范》中岩石矿物样品化学成分分析的质量要求。该方法优化了活性炭吸附测金的试验条件,试验方法的正确度和精密度均满足要求,能满足金矿石中金的准确测定。     

A new anionic exchange stir bar sorptive extraction coating based on monolithic material for the extraction of inorganic anion

A novel anionic exchange stir bar sorptive extraction (SBSE) coating based on poly(2-(methacryloyloxy)ethyltrimethylammonium chloride-co-divinylbenzene) monolithic material for the extraction of inorganic anion was prepared. The effect of preparation conditions such as ratio of functional monomer to cross-linker, content of porogenic solvent on the extraction efficiencies were investigated in detailed. The monolithic material was characterized by elemental analysis, scanning electron microscopy and infrared spectroscopy. In order to investigate the extraction capacity of the new coating for inorganic anion, the new SBSE was combined with ionic chromatography with conductivity detection, Br⁻, NO₃⁻, PO₄³⁻ and SO₄²⁻ were selected as detected solutes. Several extractive parameters, including pH value and ionic strength in sample matrix, desorption solvent, extraction and desorption time were optimized. The results showed that strongly ionic strength did not favor the extraction of anlaytes. Under the optimum experimental conditions, low detection limits (S/N = 3) and quantification limits (S/N = 10) of the proposed method for the target anions were achieved within the range of 0.92–2.62 and 3.03–9.25 μg/L, respectively. The method also showed good linearity, simplicity, practicality and low cost for the extraction inorganic anions. Finally, the proposed method was successfully used to detect the two different trademarks of commercial purified water with satisfactory recovery in the range of 70.0–92.6%. To the best of our knowledge, this is the first to use SBSE to enrich inorganic anions.     

活性炭富集电感耦合等离子体原子发射光谱测定铋系超导粉中痕量铁

建立了电感耦合等离子体原子发射光谱(ICP-AES)测定超导粉中痕量铁的新方法。优化了仪器工作参数,对痕量铁测定时的基体干扰及消除干扰的方法进行了系统研究,结果表明:大量存在的基体元素产生一定基体效应,并使重现性变差,且由于铁含量甚微,仪器灵敏度不能满足测定的要求,需采用分离富集方法以提高测定结果的准确度和精密度。以三乙醇胺掩蔽基体元素铋和铜,在适宜的酸度条件下,铁与邻二氮菲生成配合物,以活性炭定量吸附,用1∶1硝酸解吸,并对分离富集条件进行了优化。对模拟标准样品进行测定,分析结果与理论值一致,相对标准偏差为2.4%,方法检出限为0.033μg.g-1。该方法已用于超导前驱粉样品中痕量铁的分析,结果令人满意,并进行了回收实验,回收率为95.6%～98.0%。