积分安培离子色谱法测定地下水中碘化物的不确定度评定

本文对积分安培离子色谱法测定地下水中碘化物含量的不确定度进行了评定,标准曲线采用双误差拟合法,建立了不确定度评定模型,得出几种影响测定结果的因素。     

超声波萃取-高效液相色谱法测定土壤中邻苯二甲酸酯

邻苯二甲酸酯类(PAEs)是环境激素类物质中的一类化合物。文章对土壤中6种被美国EPA列入"优先监测污染物名单"的PAEs类物质邻苯二甲酸二甲酯(DMP)、二乙酯(DEP)、二丁酯(DBP)、邻苯二甲酸二(2-乙基己基)酯(DEHP)、二辛酯(DOP)、丁基苄基酯(BBP)邻苯二甲酸酯经超声波萃取、柱层析净化后,采用高效液相色谱法测定。对影响加标回收率的实验条件如萃取溶剂比例、萃取时间和萃取溶剂的选择等进行优化。方法回收率为94.1%～108.2%,相对标准偏差(RSD,n=7)为0.70%～2.42%,方法检出限为0.003～0.009μg/g。建立的方法样品前处理简单、快速,溶剂用量少,液相色谱法分析6种PAEs类物质仅用10 min,适用于大批量土壤样品中PAEs类物质的测定。     

在线渗析-离子色谱法测定土壤中有效氟

土壤样品经超声波超声静置,提取上清液,经渗析进入色谱柱,采用Metrohm A Supp 4-250阴离子交换柱,以1.8 mmol/L碳酸钠-1.7 mmol/L碳酸氢钠混合溶液作为流动相,用在线渗析技术与离子色谱法联用测定土壤中的有效氟。与常规方法相比,建立的方法操作简单,避免了繁琐的样品前处理。加标回收率为90.5%～95.7%,精密度(RSD,n=6)为1.60%。该方法具有高效、快速、灵敏等特点,能够用于环境土壤样品中有效氟的检测。     

冀北凹陷高于庄组与洪水庄组在岩芯、露头中多赋存态生物标志物的对比

利用气相色谱-质谱联用仪对采自燕山地区冀北凹陷的中元古界长城系高于庄组(Chg)灰岩和蓟县系洪水庄组(Jxh)泥页岩露头和岩芯中不同赋存状态生物标志物进行了分析.正构烷烃和萜类生物标志物显示从高于庄组(Chg)到洪水庄组(Jxh)生源由浮游类和底栖类为主转变为浮游类为主,而沉积水体的盐度则由高变低.露头样品和相应岩芯中...     

祁连山冻土区天然气水合物气体组分的气相色谱法测定

建立了气相色谱法测定祁连山冻土区天然气水合物C1-C5气体纽分的分析方法,对比研究了单点法与多点法校正、外标法与外标归一化法定量。以及顶空法与排水法2种气体收集方式的区别。结果表明：顶空法制备、单点法校正、外标归一化法定量计算为气相色谱法测定天然气水合物气体组分的最佳方法。方法相对标准偏差（ILSD）为0-1．06％,检出限为0．0003％-0．0127％。通过对祁连山冻土区DK一2孔10个天然气水合物样品的测定,发现C,含量为60．64％-78．76％,C：含量为8．99％-13．60％,C3含量为6．58％-21．24％,C4和C5含量较少,可见c,气体组分含量丰富,具有较低的C1／C2＋比值（1．5-3．7）,显示出明显的热解气特征。关键词：祁连山冻土区;天然气水合物：气体组成;气相色谱法     

Single Column Sequential Extraction of Ra,Nd, Th,Pa and U from a Natural Sample

A new procedure allowing the sequential extraction of Ra, Nd, Th, Pa and U from the same initial natural sample (sea or river waters, particles, sediments, rocks) is proposed. Extraction recoveries were better than 90%. Procedural blanks ranged from 80 pg (for Nd) to below 1 fg, the detection limit of the MC‐ICP‐MS used (for Pa); all were negligible compared with the amounts of elements currently determined. Based on classical anionic resins attached to a peristaltic pump allowing precise flow rate control, this procedure allowed a consequent reduction of the sample size, which improved the sampling resolution and reduced the sampling cost. It also ensured a better consistency of the samples for the five tracers.     

桑沟湾水体中有机氯农药和多氯联苯的浓度水平及分布特征

以气相色谱-电子捕获检测器(GC/ECD)分析并结合外标法,定量测定了桑沟湾海域水体中15种有机氯农药和多氯联苯类化合物的含量.结果表明:桑沟湾海域表层水体中有机氯农药浓度范围为20.34～52.86 ng/L,底层水中的浓度范围为31.7～58.68 ng/L.该海域水体中共检出有机氯农药6种,DDTs类化合物是水体...     

基于反相C8色谱柱的海洋浮游藻色素高效液相色谱分析方法有效性验证

对一种海洋浮游藻色素高效液相色谱分析方法进行了有效性验证。该方法使用反相C8色谱柱,以甲醇、乙腈和丙酮为流动相,并在流动相中添加吡啶/醋酸溶液作为修饰剂改善色素峰的分离效果。结果表明,4种色素标准在一定的浓度范围内线性关系良好,叶绿素a的线性范围为189.6~18 960μg/L,叶绿素b为89.2~8 920μg/L,β,β-胡萝卜素为7.77~777.2μg/L,叶黄素为15.28~1 528μg/L。除β,β-胡萝卜素外各色素标准的回收率在不同浓度下均在90%以上,相对标准偏差也普遍低于5%。在4个参考藻种和123个胶州湾现场样品中共检测出37种色素,一些关键的特征色素均获得了良好的分离效果。该方法操作简便,具有分离度好、灵敏度高、重复性好、回收率高等优点,适用于培养的藻种和现场样品中的海洋浮游藻色素分析。     

黑海参脂肪酸的气相色谱/质谱法分析

黑海参(Holothuria atra)体壁经Folch 法提取总脂, 用HCl-甲醇进行甲酯化处理, 以气相色谱/质谱法分析总脂中的脂肪酸组成。从黑海参中共分析出28 种化合物, 包括25 种脂肪酸甲酯和3 种脂肪醛二甲基缩醛。黑海参体壁中的饱和脂肪酸含量为22.93%, 以C_16:0(5.49%)和C_18:0(4.38%)为主; 不饱和脂肪酸含量为65.19%, 其中单不饱和脂肪酸33.86%, 主要为C_20:1(n-9)(15.90%); 多不饱和脂肪酸为31.33%, 主要为C_20:4(n-6)(19.57%)和C_20:5(n-3)(5.86%)。脂肪醛二甲基缩醛含量为7.28%, 表明黑海参体壁总脂中含有较丰富的缩醛型甘油酯。     

Purification and characterization of acetylcholinesterase from brain tissues of Oreochromis aurea and its application in environmental pesticide monitoring

Acetylcholinesterase (AChE) plays an important role in enzyme-based detection of pesticides in the environment. In this paper, AChE from the Triton X-100 extract of brain tissues of Oreochromis aurea was purified by (NH₄)₂SO₄ fractional precipitation, Sephadex G-100 gel filtration, and DEAE-cellulose ion exchange chromatography. Certain biochemical characterizations of the purified enzyme and inhibition of pesticides on the enzyme were also studied. The specific activity of this purified enzyme was 20.628 U/mg protein, fold of purification was 139, and recovery was 22.1%. The optimal temperature of this enzyme was between 35–40 °C, and optimal pH was between 7.5–8.0. The Michaelis constant (K_m) for acetylthiocholine iodide was 0.183 mmol/L. The enzyme activity was inhibited by excess substrate, and optimal substrate concentration was 6 mmol/L. Four pesticides (dichlorvos, phoxim, triazophos, and methomyl) exhibited strong inhibitions on this enzyme with IC₅₀ less than 5 μg/mL. This study suggests that Oreochromis aurea (tilapia) could be a good enzyme source for pesticide monitoring in water environments.