气相色谱-质谱法分析化妆品中16种香精香料

建立了用毛细管气相色谱质谱测定化妆品中16种香精香料的方法.样品用甲醇超声提取,经高速冷冻离心,清液经干燥脱水过0.5 μm滤膜过滤,直接注入气相色谱质谱进行分析.经过GC-MS分析,用选择离子和保留时间定性,外标法定量.16种香精香料的回收率为：82.3%～108.2%,精密度为（以相对标准偏差表示）：1.6%～4.7%,检出限均为10 mg/kg.该方法准确度和灵敏度高,样品用量少,前处理简单,可同时测定化妆品中16种香精香料.     

冻融法提取猪血纤维蛋白原

利用纤维蛋白原在低温下可形成絮状沉淀的性质,以样品中纤维蛋白原含量及提取率为考查指标,采用冻融法从猪血中提取纤维蛋白原.确定提取条件为:将抗凝血浆在-20 ℃温度下冷冻12 h,经4 ℃解冻,低温离心收集纤维蛋白原样品.样品中纤维蛋白原含量达82.6%,提取率达91.0%,符合静脉注射纤维蛋白原要求.     

食物或食物原材料中特定属的植物的定量PCR检测方法

一种根据PCR技术测定食物或食物原材料中的特定属的植物量的方法，包括：（1）提供修正样品，其中来自作为检测靶的特定属的植物样品和标准植物样品的混合比率预先确定，并从该样品中提取基因组DNA；（2）通过向作为试验受试者的食物或食物原材料中添加已知量的标准植物样品来制成测试样品，并从该样品提取基因组DNA；（3）用引物和这些基因组DNA实施定量。     

一种瘦肉精类检测方法

公开(公告)号:CN106546545A公开(公告)日:2017.03.29申请(专利权)人:无锡艾科瑞思产品设计与研究有限公司摘要本发明公开了一种瘦肉精类检测方法,取5~12 g待测样品,绞碎至粒径0.18~0.28 mm(60~80目),加入15~30mL高氯酸溶液,在70~80℃的温度下超声提取20~30 min,冷却至室温,离心,取上清液,沉淀加4~8 mL高氯酸溶液洗     

纳米TiO_2对PCR体系中DNA合成的影响及其机理研究

研究纳米TiO2对PCR体系中DNA合成的影响及其作用的分子机制.方法是把不同浓度的纳米TiO2直接加入PCR体系中,观察其对DNA合成量的影响;把与纳米TiO2预先混合的聚合酶、引物或模板的上层清液及沉淀分别加入到PCR体系中,观察预先相互作用对DNA合成量的影响;并用聚丙烯酰胺凝胶电泳和紫外可见光谱方法分析其作用的分子机制.结果表明锐钛矿型纳米TiO2对PCR体系中的DNA合成有浓度依赖性的抑制作用,且抑制作用强于微米级;聚合酶的上层清液、引物的沉淀、模板的上层清液与沉淀均有DNA的合成,但合成量均小于纳米TiO2直接加入PCR时的DNA的合成量;综合紫外可见光谱和电泳实验,认为避光条件下,锐钛矿型纳米TiO2抑制DNA合成的主要原因是对聚合酶、引物和模板的吸附作用,其中包括化学吸附和物理吸附,作用强度以引物最强,模板居中,聚合酶最弱,为进一步研究纳米TiO2对DNA的损伤及其生物毒性提供了理论基础.     

高效液相色谱-串联质谱法测定食品中的尿素、缩二脲与双氰胺

建立了高效液相色谱-串联质谱法同时检测食品中尿素、缩二脲和双氰胺的方法。样品经水浸泡并混匀,加入乙腈沉淀蛋白,通过冷冻离心去除脂肪,取清液挥干后用1.0 mL 70%乙腈水溶液复溶、过膜。采用电喷雾负离子电离（ESI+）模式和多反应监控（MRM）扫描模式,外标法定量。该方法在0.1~20.0 mg/L范围内线性关系良好,相关系数（r2）大于0.995。尿素、缩二脲和双氰胺的检出限分别为0.03、0.05、0.01 mg/L,定量下限分别为0.08、0.10、0.03 mg/L。加标水平为5.0、10.0、20.0 mg/kg时,尿素、缩二脲和双氰胺的平均回收率为70%~99%,相对标准偏差为0.42%~8.0%。该方法简便、灵敏、精确,适用于食品中尿素、缩二脲和双氰胺的检测。     

索氏提取-全二维气相色谱法测定化工区江滩沉积物中20种有机氯农药和7种多氯联苯的含量

取污染区沉积物,除去其中的异杂物后充分混匀。称取混匀样品10.00g,加入适量经过在400℃烘烤4h的无水硫酸钠并充分混合拌匀,研磨成细粒状。将此样品全部装入滤纸套筒中,并置于索氏提取器中,加入体积比为1∶1的正己烷-丙酮混合溶液250 mL,在回流速率为10次·h^-1条件下提取8~12h(一般可采取多个样品同时提取过夜的操作方式)。收集所有提取液,混匀后将经活化处理的铜片置于此提取液中4~6h除去硫化物。过滤除去沉淀,滤液浓缩后经以硅酸镁为载体的固相萃取柱净化。用体积比为9∶1的正己烷-丙酮混合溶液15mL洗脱固相萃取柱,收集洗脱液经浓缩至1.0mL后,供色谱分离及测定。在此测定溶液中存在20种有机氯农药(OCPs)及7种多氯联苯(PCBs)共27种化合物。待测物在非极性一维TG-35MS色谱柱上按其沸点规律分离后,流出液经调制器聚焦后迅速升温(调制周期为4s)并送入极性二维DB-1色谱柱按被测物的极性差异分离。两柱的组合达到上述27种化合物的良好分离。采用电子捕获检测器对27种化合物进行检测。上述27种化合物的质量浓度均在1.0~200.0μg·L^-1内与其对应的峰面积之间呈线性关系,其检出限(3.14s)为0.017~0.087μg·kg^-1。按标准加入法进行回收试验,测得回收率为72.0%~96.3%,测定值的相对标准偏差(n=6)为2.1%~11%。     

反相高效液相色谱法测定烤烟叶片发育过程中的类胡萝卜素类物质

建立了采用反相高效液相色谱测定烤烟叶片中类胡萝卜素的方法。烤烟叶片先用含0.1%丁基羟基甲苯（BHT）的90%丙酮水溶液萃取,然后加入0.1 g醋酸铅,于4 ℃下以10000 r/min离心5 min以去除蛋白质。色谱柱为 C18反相柱(3.9 mm i.d.×150 mm, 5 μm)。流动相:A,甲醇-异丙醇(体积比为1∶1）;B,超纯水。洗脱程序:0~10 min,70%A+30%B;10~17 min,100%A;17~30 min(90%A+10%B)。流速：0.5 mL/min。进样量:10 μL。检测波长:450 nm。该方法简化了样品的前处理过程,4种类胡萝卜素物质的加标回收率为91.77%~97.42%,相对标准偏差为 3.46%~0.98%。用该方法研究了烤烟发育过程中类胡萝卜素含量的变化规律,获得了与文献较为一致的结果。     

酶解-高效液相色谱法检测麦片和啤酒中β-葡聚糖的含量

用纤维素酶将样品提取液中的β-葡聚糖酶解为葡萄糖,高效液相色谱-示差折光检测葡萄糖,从而确定样品中β-葡聚糖的含量.0.1g粉碎后的麦片用1mL80%乙醇洗涤,5mL 水提取,检测提取液中β-葡聚糖的含量.用该方法检测标准物质大麦,回收率大于72.0%,相对标准偏差为2.5%,检出限为2%.10mL 啤酒样品用40mL95%乙醇沉淀,离心,沉淀物于80℃烘干,用1.8mL水溶解,测定溶液中β-葡聚糖的含量.啤酒中β-葡聚糖的检出限为40mg/L.方法可对大麦和啤酒中β-葡聚糖含量进行检测.     

三氯乙酸法测定烟叶中蛋白质含量

烟叶中蛋白质的含量与烟草的品质息息相关.如何快速、准确地测定烟叶中蛋白质含量则显得尤为重要.本实验通过对烟叶蛋白质抽提液的最佳浓度、蛋白质沉淀剂的最佳浓度及加入量进行确定,探索出了一种适合于测定烟叶中蛋白质含量的方法:室温条件下,用浓度为8 mol·L-1的尿素溶液充分抽提烟叶中的蛋白质(抽提时间大于6 h),12 000 r/min离心20 min后仅留上清液,将所得上清液稀释4倍后加入3%三氯乙酸,静置10 min,充分沉淀上清液中的蛋白质,之后再次12 000 r/min离心20 min后弃上清,留沉淀,将沉淀加入丙酮清洗后烘干至恒重,达到恒重的沉淀质量即为该烟叶中蛋白质的质量.     

Pressurized liquid extraction of lipids for the determination of oxysterols in egg-containing food

Pressurized liquid extraction (PLE, ASE) was compared with the Folch procedure (a solid-liquid extraction with chloroform/methanol 2:1, v/v) for the lipid extraction of egg-containing food; the accuracy of PLE for the quantitative determination of oxysterols in whole egg powder was evaluated. Samples of spray-dried whole egg, an Italian vanilla cake (Pandoro) and egg noodles were used. Two different extraction solvents (chloroform/methanol 2:1, v/v, and hexane/isopropanol 3:2, v/v) were tested at different extraction temperatures and pressures (60 degrees C at 15 MPa, 100 degrees C at 15 MPa, 120 degrees C at 20 MPa). No significant differences in the lipid recovery of the egg powder sample using PLE were found. However, PLE of the vanilla cake and egg noodles with the chloroform/methanol mixture was not selective enough and led to the extraction of a non-lipid fraction, including nitrogen-containing compounds. In the same samples, the pressurized hexane/isopropanol mixture gave a better recovery result, comparable to that obtained using the Folch method. Cholesterol oxidation products of the Folch extract and the pressurized liquid extract of spray dried egg powder (obtained with hexane/isopropanol 3:2, v/v, at 60 degrees C and 15 MPa) were determined by gas chromatography. PLE performed under these conditions is suitable to replace the Folch extraction, because the differences between the two methods tested were not statistically significant. Moreover, PLE shows important advantages, since the analysis time was shortened by a factor of 10, the solvent costs were reduced by 80% and the use of chlorinated solvents was avoided.     

冻干粉针用溴化丁基胶塞中溴化物的迁移及安全性评价

建立了对溴化丁基胶塞中溴化物的提取方法,考察了胶塞中溴化物在冻干粉中的浸出水平. 采用IonPac AS 11-HC色谱柱(4.0 mm×250 mm)和IonPac AS 11-HC保护柱(4.0 mm×50 mm),24 mmol/L KOH淋洗液等度洗脱,AERS 500(4 mm)阴离子抑制器及电导检测器,抑制器电流60 mA,柱温30 ℃,流速1.0 mL/min. 溴化物在0.2~10.0 mg/L浓度范围内线性关系良好(r＝0.999 9),检出限(LOD)为0.007 mg/L. 冻干粉针用溴化丁基胶塞以30%异丙醇水溶液为提取溶剂,80 ℃下保持7 h后测定提取液中溴化物含量. 冻干粉采用超纯水复溶后直接测定溴化物迁移量,迁移试验平均回收率为98.1%~104.3%,相对标准偏差(RSD,n=6)为2.9%~4.3%. 方法可用于包材相容性研究中实际样品的检测.     

原子吸收法在有机分析中的应用(Ⅰ)——油菜籽中硫代葡萄糖苷的测定

本文研究了用原子吸收法间接测定油菜籽中硫代葡萄糖苷的方法,本法可测定μmol/g量的硫代葡萄糖苷。对于含量为35.9至98.2μmol/g的样品。方法的标准偏差为2.72～7.83μmol/g,变异系数为0.0354～0.174。     

固相萃取技术-HPLC测定复方甘草片中吗啡的含量

报道了用ＳＥＰ－ＰＡＫＣ１８小预柱固相萃取技术和反相高效液相色谱法测定复方甘草片中微量吗啡含量的方法。对固相萃取条件进行了研究,最终选择１０％甲醇溶液为清洗溶液,７０％甲醇溶液为洗脱溶液,基本消除了干扰组分对测定的影响,色谱图背景吸收小,基线平稳。色谱柱为μ－ＢｏｎｄａｐａｋＣ１８柱,流动相为０．１ｍｏｌ／ＬＮａＨ２ＰＯ４溶液－甲醇（５１）,检测波长为２８６ｎｍ。平均回收率为（１０１．２±１．５）％,ＲＳＤ为１．５％。     

Density-gradient separations and analyses of macromolecules

A density gradient in a high-speed centrifuge can separate molecules, with apparent molecular weights greater than 12,000, on the basis of differences in density. The density-gradient technique was also used to identify tentatively the molecular class of an unknown precipitate from human serum.     

全自动流动注射-分光光度法测定土壤中氨氮

传统的氯化钾溶液提取分光光度法测定土壤中氨氮时,需要加入硝普钠-苯酚显色剂混匀后一定时间再加入二氯异氰尿酸钠显色剂,这个过程中人为接触苯酚等有机试剂的时间较长,对人体和环境有一定的危害;且传统的比色法显色时间至少需要5h,显色时间较长,分析效率较低.应用全自动流动注射-分光光度法测定土壤中氨氮,考察了提取试剂的厂家、浓...     

气相色谱法测定硫酸阿扎那韦中残留溶剂的含量

采用甲醇-正丁醇(体积比1:1)为稀释液配制样品, 消除乙醇、异丙醇与阿扎那韦形成的溶剂合物, 建立了气相色谱测定硫酸阿扎那韦中残留溶剂的方法.试验条件:FID检测器, 其温度为240℃; 进样口温度200℃, 分流比20:1;载体为氮气, 流速1 mL/min; 色谱柱初始温度35℃, 保持3 min, 以2℃/min的升温速率上升到70℃, 再以20℃/min的升温速率上升到220℃, 维持2 min.试验结果表明空白溶剂及样品不干扰测定, 各残留溶剂峰之间分离度良好.乙醇、丙酮、异丙醇、二氯甲烷、甲基叔丁基醚和正庚烷的检测限分别为2.063、0.575、2.001、4.379、0.875、0.504 μg/mL, 方法专属、灵敏.且上述溶剂分别在5.16~751.23、1.74~722.29、5.00~754.03、13.27~89.79、2.65~750.12、1.53~749.43 μg/mL范围内, 其质量浓度与峰面积的线性关系良好(r为0.999 0~1.000 0).方法的RSD均低于5.0%, 回收率结果均介于90%~110%之间, 方法重复性及准确度较好.可适用于硫酸阿扎那韦中的残留溶剂的测定.     

Mixing characteristics of a bubble mixing microfluidic chip for genomic DNA extraction based on magnetophoresis: CFD simulation and experiment

Mixing a small amount of magnetic beads and regents with large volume samples evenly in microcavities of a microfluidic chip is always the key step for the application of microfluidic technology in the field of magnetophoresis analysis. This article proposes a microfluidic chip for DNA extraction by magnetophoresis, which relies on bubble rising to generate turbulence and microvortices of various sizes to mix magnetic beads with samples uniformly. The construction and working principle of the microfluidic chip are introduced. CFD simulations are conducted when magnetic beads and samples are irritated by the generation of gas bubbles with the variation of supply pressures. The whole mixing process in the microfluidic chip is observed through a high-speed camera and a microfluidic system when the gas bubbles are generated continuously. The influence of supply pressure on the mixing characteristics of the microfluidic chip is investigated and discussed with both simulation and experiments. Compared with magnetic mixing, bubble mixing can avoid the magnetic beads gather phenomenon caused by magnetic forces and provide a rapid and high efficient solution to realize mixing small amount of regents in large volume samples in a certain order without complex moving structures and operations in a chip. Two applications of mixing with the proposed microfluidic chip are also carried out and discussed.     

Counter-current extraction and separation of U(VI) from a mixture of U(VI)–Th(IV)–Y(III) using tris-2-ethyl hexyl phosphate (TEHP)

Evaluation of tris-2-ethyl hexyl phosphate (TEHP) for counter-current extraction and separation of U(VI) from a mixture of U(VI)–Th(IV)–Y(III) from nitric acid medium was carried out under wide experimental conditions. Batch extraction studies were carried out to investigate the effect of nitric acid concentration in feed solution, U(VI)/Th(IV) ratio and extractant concentration and the results were compared with established solvent such as tri-n-butyl phosphate (TBP) for separation of U(VI) from nitric acid medium. McCabe–Thiele diagrams for extraction as well as stripping of U(VI) were constructed under simulated conditions. Based on batch experiments, six stage counter-current extraction studies were conducted under various TEHP concentration and it was observed that 0.1 M TEHP/n-paraffin was most suitable for selective recovery of U(VI) from a mixture of U(VI)–Th(IV). An optimized condition, 0.1 M TEHP/n-paraffin, 2 M HNO₃ in feed and six number of stages was evaluated for selective extraction and stripping of U(VI) from a solution containing mixture of U(VI)–Th(IV)–Y(III) in nitric acid medium. The U(VI) in strip solution was precipitated using 30 % H₂O₂ at pH ~3. Average particle size of the final precipitate was found to be ~33 μm.     

Determination of spices in food samples by ionic liquid aqueous solution extraction and ion chromatography

In the present work, a novel method to extract three kinds of spices, namely vanillin, ethyl vanillin and ethyl maltol from food products such as biscuit, chocolate and milk powder was developed. 1-Octyl-3-methylimidazolium chloride([Omim]Cl) aqueous solution was selected as the extracting medium. A 0.5 g powder of food product was extracted by 5.0 mL of [Omim]Cl aqueous solution(0.3 mol/L, pH 6.0) under ultrasonication at 50 8C, and then the extract was centrifuged for 10 min at 4000 rpm. The extract was filtered through a syringe filter and injected into ion chromatography system for analysis. The separation of the three spices was carried out on an anion exchange column. The detection wavelength was set at 280 nm. Compared with traditional extraction solvents, [Omim]Cl aqueous solution displayed particular advantages. The applicability of the proposed method to real sample was confirmed. Under the optimal conditions, good reproducibility of extraction performance was obtained, with the relative standard deviation(RSD) values ranging from 1.9% to 6.3%. The recoveries of spiked samples were between 79.8% and 95.8%. The detection limits(LOD, S/N = 3) of vanillin, ethyl vanillin and ethyl maltol were in the range of 20–45 mg/kg. The use of ionic liquid aqueous solution as extraction solvent was operationally easy and environmental-friendly.