SPE-LC-MS/MS同时测定水中9种β-内酰胺类抗生素

建立了以固相萃取-高效液相色谱串联质谱同时检测水体中9种β-内酰胺类抗生素(阿莫西林、头孢克洛、氨苄西林、头孢氨苄、头孢噻肟、头孢唑啉、青霉素G、头孢噻呋、青霉素Ⅴ)的检测方法。以Bond Elut Plexa PAX萃取小柱富集浓缩水样。对样品前处理过程中的上样p H、洗脱液进行了优化,以获得最高回收率。采用0.1%甲酸(V/V)-1 g/L甲酸铵水溶液和乙腈作为液相流动相,进行梯度洗脱。在HPLC-MS/MS多反应监测模式下进行定性定量分析。最终确定的实验条件为:上样p H为6,以4 m L 5%甲酸-甲醇(V/V)溶液进行分批洗脱。方法对9种抗生素的检出限为0.12~1.49 ng/L,加标回收率61.42%~108.08%,相对标准偏差为(n=3)2.39%~8.29%。并对大连近岸水体8个采样点水样进行了初步检测,每个采样点都有目标抗生素检出,总质量浓度在28.77~2 549 ng/L之间。除青霉素V类外各抗生素均有检出,青霉素G的检出次数与检出总质量浓度最高。结果表明,所建立的方法高效、灵敏、可靠,可用于水体中多种β-内酰胺类抗生素的分析。     

超高效液相/串联质谱法测定水中苯甲酰脲类农药残留

建立了固相萃取(SPE)-超高效液相色谱/大气压化学电离源/三重四极杆串联质谱(UPLC-MS/MS)同时测定水中7种苯甲酰脲类杀虫剂残留的方法。过滤后的样品经HLB固相萃取柱富集净化后,目标化合物经10 mL二氯甲烷洗脱并浓缩,1 mL甲醇定容后,采用BEH C18柱,以水(5 mmol/L乙酸铵)-乙腈作为流动相进行梯度洗脱,采用串联质谱作为检测器进行检测。7种苯甲酰脲类杀虫剂在相关线性范围内线性良好(r=0.999 1～0.999 5),回收率为71.8%～114%,相对标准偏差为3.3%～18.8%,方法检出限为7.0～16.0 ng/L。该方法快速,灵敏度高,适用于测定水体中7种苯甲酰脲类杀虫剂的残留。     

SPE-RRLC-MS/MS法测定制药废水中青霉素G

建立了利用固相萃取-高分离度快速液相色谱-串联质谱(SPE-RRLC-MS/MS)测定制药废水中青霉素G残留的方法。水样以30%硫酸锌+20%亚铁氰化钾作为沉淀剂沉淀蛋白质后,上清液采用Oasis HLB固相萃取柱富集和净化,以0.01 mol/L乙酸铵溶液(加0.1%甲酸)+乙腈作为流动相进行等度洗脱,经Agilent Plus C18柱分离后,在串联质谱ESI(+)源下进行MRM检测。该方法的青霉素G检出限(S/N=3)为0.02μg/L,目标物在0.0020～1.0 mg/L范围内线性关系良好,线性相关系数为0.9997。在0.20,1.0,2.0μg/L添加水平平均回收率为74.6%～101.4%,相对标准偏差为4.49%～8.17%。该方法灵敏度高、重现性好、定性定量准确,可满足制药废水中青霉素G残留检测的要求。     

液质联用法测定水中六溴环十二烷和四溴双酚A

建立了固相萃取(SPE)-超高效液相色谱/三重四极杆串联质谱(UPLC-MS/MS)同时测定水中六溴环十二烷和四溴双酚A的方法。过滤后的样品酸化后经C18固相萃取柱富集净化后,采用BEH C18柱,以水-甲醇作为流动相进行梯度洗脱,采用串联质谱进行检测。4种目标化合物在相关线性范围内线性良好(r=0.997 8~0.999 4),回收率为77.2%~91.3%,相对标准偏差为8.4%~13.8%,方法检出限为0.09~0.15 ng/L。该方法快速,灵敏度高,适用于测定水体中4种溴代阻燃剂的痕量残留。     

超快速液相色谱-串联质谱法测定制药废水中阿维菌素的研究

建立了采用固相萃取-超快速液相色谱-串联质谱（SPE-RRLC-MS/MS）测定制药废水中阿维菌素残留的方法.水样经离心、沉淀蛋白质后,上清液采用HLB固相萃取柱富集和净化;以0.1%甲酸水溶液和50%～90%甲醇为流动相,采用AgilentPlusC18柱进行RRLC分离,在串联质谱ESI（＋）模式下采用多反应监测模...     

超高效液相色谱串联质谱法同时测定叶菜中13种抗生素

建立了超高效液相色谱串联三重四极杆质谱(UPLC-MS/MS)同时检测叶菜类蔬菜中磺胺类、喹诺酮类、大环内酯类13种抗生素的分析方法.优化蔬菜基质中抗生素的提取液种类、净化方式、洗脱液种类,以及探讨环境变化和实验条件对实验结果的影响后,确定最优方案为称取500 mg的蔬菜样品,加入20 mL甲醇-Mcllvaine-Na_2EDTA溶液,超声和离心提取3次后,旋转蒸发至20 mL过HLB固相萃取柱.以6 m L甲醇洗脱,收集洗脱液,氮吹近干,用乙腈∶水(体积比2∶8)混合溶液复溶,离心、过滤后采用UPLC-MS/MS进行检测.流动相A相为1‰的甲酸水溶液,B相为乙腈,梯度洗脱.结果显示,小白菜在300ng·g~(-1)加标时,13种抗生素的加标回收率为38. 05%～96. 97%,150 ng·g~(-1)时,加标回收率为34. 52%～111. 10%,50 ng·g~(-1)时,加标回收率为41. 75%～107. 13%,相对偏差RSD值均小于8. 68%.检出限为0. 4～1 ng·g~(-1)、定量限为1. 5～3 ng·g~(-1),在不同种类的叶菜上也表现出较好的提取和回收效率,具有较好的分析应用效果.实际的样品检测发现,4种叶菜不同程度地检测出了抗生素的残留.总的含量范围(以干重计)为1. 59～32. 01 ng·g~(-1).小白菜所含抗生素含量最高,其次为白菜、生菜和芫荽.磺胺二甲基嘧啶为叶菜中含量最高的抗生素种类.各抗生素检测出的含量虽很低,但仍不能忽略长期食用带来的潜在健康风险.     

SPE-UFLC-MS/MS法测定制药废水中四环素类抗生素

文章建立了利用固相萃取-超快速液相色谱-串联质谱(SPE-UFLC-MS/MS)测定制药废水中四环素类抗生素(土霉素、四环素和金霉素)残留的方法。水样经(30%硫酸锌+20%亚铁氰化钾)溶液作为沉淀剂沉淀蛋白质后,上清液采用Oasis HLB固相萃取柱富集和净化,以(0.1%甲酸溶液+乙腈)为流动相进行梯度洗脱,经Agilent ZORBAX SB C18柱分离后,在串联质谱ES(I+)模式下进行MRM检测。该方法四环素类抗生素检出限(S/N=3时)0.02μg/L,3种目标物在0.010¹.0 mg/L范围内线性关系良好,线性相关系数在0.998 21.0 mg/L范围内线性关系良好,线性相关系数在0.998 2⁰.999 8之间。在0.20、0.40和0.60μg/L添加水平,各组分的回收率在80.8%0.999 8之间。在0.20、0.40和0.60μg/L添加水平,各组分的回收率在80.8%⁹7.2%之间,相对标准偏差在5.31%97.2%之间,相对标准偏差在5.31%⁹.92%之间。该方法可满足制药废水中四环素类抗生素残留检测的要求。     

固相萃取高效液相色谱法测定水中邻苯二甲酸酯类环境激素

建立了以HLB固相萃取柱和反相液相色谱法测定水中8种邻苯二甲酸酯类环境激素的方法,利用正交试验进行萃取条件的优化,确定固相萃取的优化条件为:洗脱剂组成为V(甲醇)∶V(乙醚)=1∶19,洗脱速率为1 0mL min,洗脱体积为9mL,清洗剂组成为V(甲醇)∶V(水)=1∶19。8种物质峰面积对浓度进行线性回归的相关系数均大于0 999,最低检出限为0 10～0 62μg L,回收率为75 1%～115 5%,相对标准偏差为0 9%～2 2%。同时将该方法应用于废水中邻苯二甲酸酯类环境激素的测定,检出DEP,BBP,DBP和DEHP4种邻苯二甲酸酯类环境激素。      

SPE-HPLC法测定城市污水中8种四环素类抗生素

建立了一种固相萃取(solid phase extraction,SPE)-高效液相色谱(high performance liquid chromatography,HPLC)法同时测定城市污水中8种四环素类抗生素的分析方法。对色谱条件进行了优化,结果表明,在350 nm的检测波长下,以甲醇-乙腈(2∶3)为流动相A,0.1%三氟乙酸(p H=2.0,含0.01 mol/L草酸铵)为流动相B,流动相之比为2∶3时,8种抗生素的分离效果最好。对固相萃取条件进行了优化,结果表明,采用HLB固相萃取柱,调节样品p H=2,以3 m L 0.1%三氟乙酸-甲醇溶液洗脱,8种四环素类抗生素的加标回收率达到了77.4%~113.3%,相对标准偏差为1.5%~9.9%。3倍信噪比下,8种四环素类抗生素的检出限为1.61~12.50 ng/L。采用此方法对北京某污水处理厂进水进行检测,8种四环素类抗生素均有检出,浓度范围为0.10~1.90μg/L。     

LC-MS/MS用于地表水中抗生素快速筛查

建立了固相萃取-反相高效液相色谱-质谱法对水体中磺胺类、四环素类、头孢类、氯霉素等20种抗生素筛查方法。采用水(含0.1%甲酸,0.5 mmol/L甲酸铵):甲醇(含0.1%甲酸,0.5 mmol/L甲酸铵)作流动相,分别使用电喷雾正离子源和负离子源进行离子化,动态多反应监测方式(DMRM)对20种抗生素的母离子及子离子进行监测。采用外标法定量时,抗生素方法的检出限为0.5~2.5 ng/L,R0.99,回收率介于79.2%~125.5%。     

Effects of two sludge application on fractionation and phytotoxicity of zinc and copper in the soil

The potential harm of heavy metals is a primary concern in application of sludge to the agricultural land. A pot experiment was conducted to evaluate the effect of two sludges on fractionation of Zn and Cu in soil and their phytotoxicity to pakchoi. The loamy soil was mixed with 0%, 20%, 40%, 60% and 80% (by weight) of digested sewage sludge (SS) and composted sludge (SC). The additions of both sludges caused a significant raise in all fractions, resulting in that exchangeable (EXCH) and organic bound (OM) became predominance of Zn and organic bound Cu occupied the largest portion. There was more available amount of Zn and Cu in SS treatments than SC treatments. During the pot experiment, the concentration of Zn in EXCH, carbonate (CAR) and OM and Cu in EXCH and OM fractions decreased in all treatments, so their bioavailability reduced. Germination rate and plant biomass decreased when the addition rate was high and the best yield appeared in 20% mixtures at the harvest of pakchoi. The two sludges increased tissue contents of Zn and Cu especially in the SS treatments. Zn in pakchoi was not only in relationship to ΔEXCH and ΔCAR forms but also in ΔOM forms in the sludge-soil mixtures. Tissue content of Cu in pakchoi grown on SC-soils could not be predicted by ΔEXCH. These correlation rates between Zn and Cu accumulation in pakchoi and variation of different fractions increased with time, which might indicate that sludges represented stronger impacts on the plant in long-term land application.     

Intraspecific differences in effects of co-contamination of cadmium and

A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium (Cd)(0-10 mg/L) and arsenate (As(V)) (0-8 mg/L) on the growth parameters and accumulation of Cd and As in six wheat varieties Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongmai-8. The endpoints of wheat seedlings, including seed germination,biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties (p ＜ 0.05). The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11,Jing-411, Jingdong-8 and Zhongmai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongmai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Degradation of metabolites accumulated of benzo[a]pyrene by coupling Penicillium Chrysogenum with KMnO4

Several main metabolites of benzo[a]pyrene （BaP） formed by Penicillium chrysogenum, Benzo[a]pyrene-1,6-quinone （BP 1,6- quinone）, trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene （BP 7,8-diol）, 3-hydroxybenzo[a]pyrene （3-OHBP）, were identified by high-performance liquid chromatography （HPLC）. The three metabolites were liable to be accumulated and were hardly further metabolized because of their toxicity to microorganisms. However, their further degradation was essential for the complete degradation of BaP. To enhance their degradation, two methods, degradation by coupling Penicillium chrysogenum with KMnO4 and degradation only by Penicillium chrysogenum, were compared; Meanwhile, the parameters of degradation in the superior method were optimized. The results showed that （1） the method of coupling Penicillium chrysogenum with KMnO4 was better and was the first method to be used in the degradation of BaP and its metabolites; （2） the metabolite, BP 1,6-quinone was the most liable to be accumulated in pure cultures; （3） the effect of degradation was the best when the concentration of KMnO4 in the cultures was 0.01% （w/v）, concentration of the three compounds was 5 mg/L and pH was 6.2. Based on the experimental results, a novel concept with regard to the bioremediation of BaP-contaminated environment was discussed, considering the influence on environmental toxicity of the accumulated metabolites.     

Impact of atrazine and nitrogen fertilizers on the sorption of chlorotoluron in soil and model sorbents

Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.