饮用水中卤代乙酸分析方法研究

本文在研究了分析饮用水中的三种卤代乙酸(HAA3)[一氯乙酸(MCCAA)、二氯乙酸(DCAA)、三氯乙酸(TCAA)]液-液萃取衍生气相色谱法的多种条件影响后,提出了在酸性条件下,以含1,2-二溴丙烷(1,2-DBP)内标的甲基叔丁基醚(MtBE)萃取,萃取液用10%硫酸甲醇溶液衍生2h,再用饱和碳酸钠中和,然后通过气相色谱(常用柱HP-5,电子捕获检测器ECD)分离检测.本法检出限为MCAA10μg/L,S/N＞10;DCAA12μg/L,S/N＞80;TCAA4μg/L,S/N＞100;自来水样加标回收率为86%～110%.     

液液萃取-甲醇衍生-气相色谱-质谱法测定饮用水中卤乙酸

目的建立液液萃取、酸化甲醇衍生、气相色谱-质谱法测定饮用水中的3种卤乙酸(一氯乙酸Mc AA、二氯乙酸Dc AA、三氯乙酸Tc AA)的方法,为饮用水中卤乙酸检测提供参考。方法样品酸化后只加入无水硫酸钠以促使水相和有机相分离,采用含内标1,2-二溴丙烷(1,2-DBP)的甲基叔丁基醚(Mt BE)萃取卤乙酸后,用新配制的硫酸酸化甲醇溶液衍生成卤乙酸甲酯,再用气相色谱-质谱仪测定,内标法定量。结果 3种卤乙酸在5.0μg/L~100μg/L时保持良好线性关系,检出限(3S/N)为0.06μg/L~0.21μg/L,加标回收率为78.8%~103.9%,相对标准偏差(RSD)为4.8%~5.1%(n=6)。结论该方法操作简便、试剂消耗少、回收率稳定、结果准确,适合饮用水中3种卤乙酸的检测。     

吹扫捕集-气相色谱/质谱法测定饮用水中的10种三卤甲烷

目的建立饮用水中10种三卤甲烷的吹扫捕集-气相色谱/质谱检测方法。方法通过吹扫捕集,将目标化合物从水中吹脱,并用捕集阱同时吸附,热解吸后利用气相色谱分离,质谱检测,内标法定量。结果该方法三氯甲烷、二氯一溴甲烷、一氯二溴甲烷、三溴甲烷的线性范围为0.50μg/L~25μg/L,一氯一溴一碘甲烷、二氯一碘甲烷、二溴一碘甲烷、一氯二碘甲烷、一溴二碘甲烷、三碘甲烷的线性范围为0.050μg/L~2.5μg/L,线性相关系数均0.998,检出限为0.5 ng/L~9.2 ng/L,加标回收率为89%~113%,相对标准偏差5%。结论本文建立的方法简便、灵敏、准确,适合饮用水中常见三卤甲烷及含碘三卤甲烷的检测。     

固相萃取-超高效液相色谱-串联质谱法测定水中4种大环内酯类抗生素

目的 建立水中4种大环内酯类抗生素(MALs)：即罗红霉素(roxithromycin,ROX)、克拉霉素(clarithromycin,CLAR)、阿奇霉素(azithromycin,AZI)、红霉素(erythromycin,ERM)的固相萃取-超高效液相色谱-串联质谱测定方法。方法 用HLB小柱富集目标分析物,甲醇洗脱,氮吹近干后用5%甲醇水定容,采用UPLC-MS/MS分离检测,内标法定量。结果 本法在5μg/L～150μg/L浓度内,线性关系良好,方法检出限为2.36×10^-4μg/L～8.87×10^-4μg/L,定量限为7.86×10^-4μg/L～2.96×10^-3μg/L,平均加标回收率为95.0%～106.9%,RSD为2.02%～8.21%。结论 本法简便、快速、灵敏,能满足末梢水中4种痕量大环内酯抗生素的检测。     

超高效液相色谱-大气压化学电离-三重四极杆质谱联用法快速测定水中苯并[a]芘

目的建立超高效液相色谱-大气压化学电离-三重四极杆质谱联用法快速检测水中苯并[a]芘。方法优化样品前处理方法、超高效液相色谱分离条件和质谱测定条件,20.0 mL水样先经环己烷2次萃取富集,萃取液氮气吹干,残渣溶于甲醇。以甲醇和水作为流动相进行梯度洗脱,在XBridge BEH C_(18)色谱柱上实现分离,正离子大气压化学电离多反应监测方式检测,采用稳定同位素稀释法定量检测水中苯并[a]芘含量。结果该方法线性范围为0.000 3～0.50μg/L,检出限为0.000 1μg/L,定量限为0.000 3μg/L,平均加标回收率在92%～100%之间,相对标准偏差在4.0%～13.0%之间。5份自来水样品中检出苯并[a]芘2份,浓度分别为0.000 11μg/L和0.000 13μg/L,但均低于方法定量限;5份河水样品均检出了苯并[a]芘,浓度为0.001 0～0.001 8μg/L。结论本方法操作简单、灵敏、准确,可适用于水中苯并[a]芘的快速测定。     

超高效液相色谱三重四极杆质谱法快速测定蜂蜜中12种大环内酯和林可酰胺类药物残留

目的:应用超高效液相色谱串联质谱联用技术,建立了蜂蜜中12种大环内酯和林可酰胺类抗生素的多残留检测方法。方法:样品用2 mol/L乙酸铵水溶液调节pH值至中性,然后用20%甲醇水超声溶解、高速离心、ACQUITY UP-LC HSS T3色谱柱分离后串联质谱电喷雾正离子多反应监测模式检测,基质匹配标准内标法定量。结果:大环内酯和林可酰胺类抗生素残留的检测限为0.1μg/kg～1.0μg/kg(S/N=3),定量限为0.3μg/kg～3.0μg/kg。平均加标回收率在94%～115%之间,相对标准偏差1.3%～14.7%(n=6)。结论:本法简便、灵敏、准确,能够快速确证检测蜂蜜中12种大环内酯和林可酰胺类抗生素的残留。     

QuEChERS结合三重四级杆气质联用法测定茶叶中15种有机氯和拟除虫菊酯类农药残留

目的建立QuEChERS结合气相色谱-串联质谱法测定茶叶中15种农药残留。方法称取茶叶粉碎样,加乙腈(1%乙酸)超声提取,经N-丙基乙二胺(PSA粉)、石墨化碳粉、中性氧化铝混合分散固相萃取后离心,上清液直接进入三重串联四级杆气质联用仪检测,基质标准曲线外标法定量。结果各种农药在10μg/L～500μg/L时线性关系良好,相关系数(r)均0.998;定量限为1μg/kg～6μg/kg;茶叶空白基质加标浓度为20μg/kg、50.0μg/kg和200.0μg/kg时,15种农药的加标回收率为76.5%～118.8%,相对标准偏差为2.35%～7.56%。结论该方法检测灵敏度高、准确性好、操作简便快速,具有良好的回收率和稳定性。较好的解决了茶叶样品本底成分复杂的基质干扰,可满足茶叶中多种常见农药残留的日常检测需求。     

饮用水中6种卤乙酸的离子色谱-电导检测法

目的建立生活饮用水中6种卤乙酸(HAAS)的离子色谱-电导检测法。方法选用离子色谱仪,Dionex IonPac AS19阴离子色谱柱;以KOH溶液梯度淋洗,可同时检测一氯乙酸(MCAA)、二氯乙酸(DCAA)、三氯乙酸(TCAA)、一溴乙酸(MBAA)、二溴乙酸(DBAA)、三溴乙酸(TBAA)以及水中多种常规阴离子。结果 6种卤乙酸在0.01~1.0mg/L的浓度范围内相关系数均可达0.9996以上,DCAA和TCAA的最小检出限分别为0.97μg/L和1.0μg/L。RSD为1.9%~3.9%之间,回收率为75%~103%。结论本方法简单、安全,且快速易行,适用于水中多种卤乙酸的同时检测。     

淋洗液在线发生离子色谱法同时测定饮用水中二氯乙酸、三氯乙酸和草甘膦

目的建立饮用水中二氯乙酸、三氯乙酸和草甘膦的淋洗液在线发生离子色谱测定方法。方法水样经Ion PAC AS19型分析柱(250 mm×4 mm)分离,以KOH为淋洗液,流速为1.00 ml/min,梯度洗脱后抑制型电导检测器检测。结果二氯乙酸、三氯乙酸和草甘膦的线性范围分别为20.0~800μg/L、20.0~800μg/L和20.0~1 000μg/L,相关系数均大于0.999,方法检出限分别为3.2μg/L、3.0μg/L和3.0μg/L,加标回收率为94.0%~110.0%,相对标准偏差为2.49%~6.98%(n=6)。结论本方法操作简便快捷,灵敏度高,结果准确可靠,适用于饮用水中二氯乙酸、三氯乙酸和草甘膦的同时测定。     

顶空固相微萃取-气相色谱法同时测定饮用水中2,4-二氯酚、2,4,6三氯酚、五氯酚

目的建立同时测定生活饮用水中2,4-二氯酚、2,4,6-三氯酚、五氯酚的简单、快速、有效、灵敏方法。方法取水样5 ml,经盐酸酸化和氯化钠饱和,60℃搅拌平衡20 min,聚丙烯酸酯萃取头(PA,85μm)萃取12 min后280℃下解吸2.5 min,用HP-5毛细管色谱柱分离,ECD检测器检测,工作曲线法定量。结果本法线性范围为0.2~10μg/L,线性回归方程相关系数为0.998 3~0.999 3,方法检出限为0.05~0.13μg/L,方法定量限为0.17~0.43μg/L。通过高、中、低个3个浓度水平的加标实验测回收率98.7%~110.5%之间,相对标准差小于1.82%~5.54%。结论本法操作简单、灵敏、环保,适合于生活饮用水中三种酚的测定。     

Gamma-linolenic acid, arachidonic acid, and eicosapentaenoic acid as potential anticancer drugs

Several in vitro studies and limited in vivo investigations showed that some cis-unsaturated fatty acids (c-UFAs) such as gamma-linolenic acid, arachidonic acid, and eicosapentaenoic acid have selective tumoricidal actions. This cytotoxic action of c-UFAs is produced by augmentation of free-radical generation and lipid peroxidation in tumor cells but not in normal cells. Moreover, lymphokines such as interferon and tumor necrosis factor seem to produce their antitumor effects by inducing the release of c-UFAs from the cell-membrane lipid pool and free-radical generation, and several anticancer drugs, especially doxorubicin and vincristine, have the capacity to augment free-radical generation and promote lipid peroxidation. Tumor cells are known to contain low amounts of c-UFAs, have decreased capacity to generate free radicals and lipid peroxides, and are highly susceptible to free radical-induced cytotoxicity compared with normal cells. In addition, c-UFAs and their products can modulate the immune response, augment the respiratory burst of neutrophils and free-radical generation by macrophages, and modify genetic damage induced by mutagens and carcinogens. These evidences, coupled with the observation that the cancer incidence is low in Eskimos on traditionally high-c-UFA diets, suggests that c-UFAs can be exploited as possible anticancer agents either alone or in combination with lymphokines and cancer chemotherapy.     

复方苯甲酸酊剂中苯甲酸及水杨酸的含量检测

目的:探索复方苯甲酸酊剂两种主要成分稳定有效的含量测定方法.方法:用中和法测定两酸的总量,用紫外分光光度法测定水杨酸的含量,从总量中减去水杨酸的含量即为苯甲酸的含量.结果:回收实验苯甲酸平均回收率为100.13%,RSD为0.73%;水杨酸平均回收率为99.95%,RSD为0.23%.结论:结合使用中和法和紫外分光光度法能较好地同时检测复方苯甲酸酊剂中两种主要成分的准确含量.     

Docosahexaenoic acid and arachidonic acid prevent essential fatty acid deficiency and hepatic steatosis

Objectives: Essential fatty acids are important for growth, development, and physiologic function. α‐Linolenic acid and linoleic acid are the precursors of docosahexaenoic and arachidonic acid, respectively, and have traditionally been considered the essential fatty acids. However, the authors hypothesized that docosahexaenoic acid and arachidonic acid can function as the essential fatty acids. Methods: Using a murine model of essential fatty acid deficiency and consequent hepatic steatosis, the authors provided mice with varying amounts of docosahexaenoic and arachidonic acids to determine whether exclusive supplementation of docosahexaenoic and arachidonic acids could prevent essential fatty acid deficiency and inhibit or attenuate hepatic steatosis. Results: Mice supplemented with docosahexaenoic and arachidonic acids at 2.1% or 4.2% of their calories for 19 days had normal liver histology and no biochemical evidence of essential fatty acid deficiency, which persisted when observed after 9 weeks. Conclusion: Supplementation of sufficient amounts of docosahexaenoic and arachidonic acids alone without α‐linolenic and linoleic acids meets essential fatty acid requirements and prevents hepatic steatosis in a murine model.     

Docosahexaenoic acid and n-6 docosapentaenoic acid supplementation alter rat skeletal muscle fatty acid composition

Background  

Docosahexaenoic acid (22:6n-3, DHA) and n-6 docosapentaenoic acid (22:5n-6, DPAn-6) are highly unsaturated fatty acids (HUFA, ≥ 20 carbons, ≥ 3 double bonds) that differ by a single carbon-carbon double bond at the Δ19 position. Membrane 22:6n-3 may support skeletal muscle function through optimal ion pump activity of sarcoplasmic reticulum and electron transport in the mitochondria. Typically n-3 fatty acid deficient feeding trials utilize linoleic acid (18:2n-6, LA) as a comparison group, possibly introducing a lower level of HUFA in addition to n-3 fatty acid deficiency. The use of 22:5n-6 as a dietary control is ideal for determining specific requirements for 22:6n-3 in various physiological processes. The incorporation of dietary 22:5n-6 into rat skeletal muscles has not been demonstrated previously. A one generation, artificial rearing model was utilized to supply 22:6n-3 and/or 22:5n-6 to rats from d2 after birth to adulthood. An n-3 fatty acid deficient, artificial milk with 18:2n-6 was supplemented with 22:6n-3 and/or 22:5n-6 resulting in four artificially reared (AR) dietary groups; AR-LA, AR-DHA, AR-DPAn-6, AR-DHA+DPAn-6. A dam reared group (DAM) was included as an additional control. Animals were sacrificed at 15 wks and soleus, white gastrocnemius and red gastrocnemius muscles were collected for fatty acid analyses.