原子荧光光谱法测定环境空气中锑

采用过氯乙烯滤膜采集环境空气中锑,盐酸-氢氟酸混酸体系微波消解滤膜,原子荧光光谱法测定锑。方法前处理操作过程简单、省时、酸用量少、环境污染小,方法的灵敏度和准确度都有很大的提高。采样体积为300L时,空气中锑的最低检出质量浓度为0.002mg／m3。     

分散液液微萃取-气相色谱/质谱法测定水中阿特拉津

建立了简便、快速、有效的分散液液微萃取(DLLME)-气相色谱/质谱技术萃取水样中痕量阿特拉津的新方法。通过试验确定最佳萃取条件。     

固相萃取-原子荧光光谱法测定土壤中的砷

采用硝酸-氢氟酸-盐酸体系微波消解土壤并结合On-Guard ⅡH柱去除消解液中重金属,原子荧光光谱法测定土壤中的砷。本方法前处理操作过程简单、省时、省力、酸用量少,砷的加标回收率为94.4％～105.6％,能够满足环境监测分析的要求。     

均匀设计优化试验条件-原子荧光法测定污泥中总砷

通过对试验条件进行优化,建立了一种改进的氢化物发生-原子荧光光谱法测定污泥中总砷的方法。采用了均匀设计〔U10*(108)〕与单因子试验相结合以研究和优化分析参数和条件。在优化的试验条件下进行总砷含量的测定,方法检出限为0.21 mg kg-1,线性范围为0.24-100μg L-1,加标回收率在91.0%-94.5%之间。测定11份有证土壤样品(浓度值10.7±0.8 mg kg-1)的相对标准偏差(RSD,n=5)为1.6%。该方法经标准样品验证后,成功用于污泥实际样品的测定,并取得满意的结果。     

地表水体中同时分析18种糖皮质激素方法的建立

建立了一种采用固相萃取-超高效液相色谱串极质谱联用系统(UPLC-MS/MS)同时测定地表水体中18种糖皮质激素的高灵敏分析方法.样品经过HLB固相萃取柱富集净化、V(乙腈)/V(乙酸乙酯)=1∶1,洗脱后,用UPLC-MS/MS测定.流动相为甲醇和0.1%乙酸水溶液(体积比),采用梯度洗脱,实现了18种目标物质的基线分离,线性范围为1.0~1 000μg·L-1.实际水样的加标回收率为65%~108%.整个分析的方法检出限(MDL)除醋酸可的松和醋酸氢化可的松为10 ng·L-1外,其他均在0.10 ng·L-1和1.0 ng·L-1之间.应用此方法于北京地表水体5个样品,检测到8种糖皮质激素,浓度范围0.20~476ng·L-1,其中曲安西龙、曲安奈德、醋酸氢化可的松和丙酸氯倍他索在地表水中首次检出,证明了该方法的有效性.     

Isolation and Identification of Antialgal Compounds from the Leaves of Vallisneria spiralis L. by Activity-Guided Fractionation (5 pp)

Background, Aims and Scope

Vallisneria spiralis Linn., a common, submerged macrophyte, is widely available in quiet waters of lakes, ponds, marshes and streams in Southeast Asia. V. spiralis plays a significant role not only in decreasing eutrophication of water body for its productivity, but also in inhibiting the growth of blue-green algae? The aim of the paper involves the isolation and identification of allelochemicals from extracts of V. spiralis by activity-guided fractionation and column chromatography.

Methods

Leaves of V. spiralis was washed free of debris, air-dried and refluxed in 95% EtOH. The extract was isolated using column chromatography and fractionation with antialgal activity. Potential allelochemicals were analyzed by high-resolution gas chromatography-mass spectrometry (HRGC-MS).

Results

Two fractions with strong antialgal activity were isolated using column chromatography and activity-guided fractionation from the extract of V. spiralis. 2-Ethyl-3-methylmaleimide, dihydroactinidiolide and 4-oxo-β-Ionone were identified in the first fraction, and 3-hydroxy-5,6-epoxy-β-ionone, loliolide, 6-hydroxy-3-oxo-α-ionone and an unknown compound in the second fraction. They had strong inhibitory effects on Microcystis aeruginosa Kütz.

Discussion

2-Ethyl-3-methylmaleimide is a byproduct of photooxidation of chlorophyll, and five other compounds identified were derivatives of β-carotene. HRGC-MS and derivatization technology were used to identify and confirm their molecular structures. The formula of the unknown compound was C16H19NO4. Metabolites of plant pigments had strong inhibitory activities on growth of algae.

Conclusions

Six compounds had been identified in V. spiralis, among them, 2-ethyl-3-methylmaleimide was the main allelochemical, and derivatives of ionone were also potential allelochemicals.

Recommendations and Perspective

. The results of our research could help us to study further mechanisms of inhibitory effect on algae and develop new potential antialgal substances.     

甲烷煤尘耦合爆炸传播特性及伤害研究

为探究煤尘质量浓度对甲烷煤尘耦合爆炸传播特性及伤害距离的影响,自制长15 m的爆炸管道系统,用体积分数为7％甲烷分别与质量浓度为0、50、100和200 g/m3的煤尘进行耦合爆炸试验,并根据质量、动量和能量守恒理论推导出最大压力计算公式.结果 表明:不同质量浓度煤尘与甲烷耦合爆炸时,最大压力均随与爆源距离的增加呈现出...     

加压流体萃取-气相色谱质谱法测定土壤和沉积物中27种拟除虫菊酯类农药

建立了加压流体萃取-气相色谱质谱法测定土壤和沉积物中27种拟除虫菊酯类农药的方法。以丙酮/正己烷(V∶V=1∶1)为萃取溶剂,在120℃和10. 3 MPa条件下静态萃取7 min,循环3次,石墨化炭黑串接氨丙基键合硅胶固相萃取柱净化,HP-5MS UI色谱柱分离,优化了提取和分析过程的重要条件。方法检出限为0. 001~0. 012 mg/kg,土壤中低、高浓度的加标回收率范围分别为68. 3%~123%和75. 3%~115%,沉积物中低、高浓度的加标回收率范围分别为67. 1%~120%和78. 6%~110%,单一目标物的相对标准偏差(RSD)均<20%(n=6)。实验结果表明,该方法消耗溶剂少、效率高、检出限低、精密度和准确度好,适用于土壤和沉积物中拟除虫菊酯类农药残留的测定。     

非全量消解-悬浮液进样火焰原子吸收光谱法测定煤灰中的铜和铅

试验了用非全量消解—悬浮液直接进样火焰原子吸收光谱法测定煤灰中的铜和铅，结果表明：铜和铅的方法检出限(3σ)分别为0．038mg／L和0．23mg／L，测定吸光度与其浓度的线性范围均为0．5mg／L—5．0mg／L，样品加标回收率在87％—97％之间，相对标准差(n＝4)小于7％。     

悬浮液进样石墨炉原子吸收法直接测定土壤、底泥中的铅、镓、钴、镍

介绍一种悬浮液进样直接测定土壤、底泥中多种微量金属元素的快速分析方法。基体改进剂的使用，适宜的原子化温度的选择，使用水相标准溶液作校准曲线成为可能．对标准作品的测定证明了此方法的精密度和准确度较好，适合于常规环境样品分析．