Levels and distributions of polychlorinated naphthalenes in sewage sludge of urban wastewater treatment plants

Over seventy congeners of polychlorinated naphthalenes （PCNs） in sewage sludge of 8 urban waste- water treatment plants （WWTPs） in Beijing were analyzed by isotope dilution, and high resolution gas chromatography/high resolution mass spectrometry （HRGC/HRMS） method, The total PCN concentrations determined in the samples range from 1.48 to 28.21 ng/g dw （dry weight） with TEQ concentrations of 0.11--2.45 pg/g dw. These levels were lower than those found in other regions, DiCNs and TrCNs were the most dominant homologues of PCNs, The similar congener profiles in all the samples suggest the similarity in certain sources, Contamination from industrial input might be the most significant source of PCNs in the sludges in this study, and thermal processes such as waste incineration and coal combustion may be another source of the PCNs contamination.     

反相离子对HPLC法同时测定盐酸二甲双胍中双氰胺和三聚氰胺的含量

建立一种简单的反相离子对HPLC方法测定盐酸二甲双胍中的双氰胺和三聚氰胺的含量.使用Hypersil ODS C18反相色谱柱(5μm;250×4.6 mm),乙腈-离子对试剂水溶液(10 mmol/L戊烷磺酸钠+10 mmol/L柠檬酸,pH为3.0,体积比10∶90)为流动相,流速1.0 mL/min,检测波长217 nm,柱温25℃.结果表明:双氰胺在0.02²0μg/mL浓度范围内线性关系良好,相关系数R=0.999 9,平均回收率为97.6%,RSD=0.29%;三聚氰胺在0.0220μg/mL浓度范围内线性关系良好,相关系数R=0.999 9,平均回收率为97.6%,RSD=0.29%;三聚氰胺在0.02⁵0μg/mL浓度范围内线性关系良好,相关系数R=0.999 9,平均回收率96.5%,RSD=0.32%.双氰胺和三聚氰胺的检出限分别为4.0 ng/mL和6.0 ng/mL.该方法简单、快速、准确、灵敏,适于同时测定盐酸二甲双胍制剂中的双氰胺和三聚氰胺的含量.     

液相色谱-质谱法测定Beagle犬血浆中利培酮及9-羟基利培酮的浓度

建立了一种LC／MS方法测定犬血浆中利培酮及其代谢产物9-羟基利培酮浓度的方法、以氯氮平为内标,使用液液萃取的方法提取待测物,经液相梯度洗脱后在质谱进行检测．液相使用Agilent eclipse XDB C18（150mm×4．6mmI．D．,5μm）色谱柱,流动相为乙睁水（10mmol·L^-1醋酸铵＋醋酸调pH至4．6）．质谱使用正离子扫描,检测离子对为利培酮的411．4→191．0和9-羟基利培酮的427．2→207．2．利培酮和9-羟基利培酮线性范围均为0．05—100ng·mL^-1,最低定量限均为0．05ng·mL^-1。日内和日间精密度均小于7．8％;方法的准确度在±8．7％．此方法可满足肌肉注射利培酮微球后犬血浆中药物浓度的测定研究的需要．     

On-line catalytic upgrading of biomass fast pyrolysis products

Pyrolysis-gas chromatography/mass spectrometry （Py-GC/MS） was employed to achieve fast pyrolysis of biomass and on-line analysis of the pyrolysis vapors. Four biomass materials （poplar wood, fir wood, cotton straw and rice husk） were pyrolyzed to reveal the difference among their products. Moreover, catalytic cracking of the pyrolysis vapors from cotton straw was performed by using five catalysts, including two microporous zeolites （HZSM-5 and HY） and three mesoporous catalysts （ZrO2＆TiO2, SBA-15 and AI/SBA-15）. The results showed that the distribution of the pyrolytic products from the four materials differed a little from each other, while catalytic cracking could significantly alter the pyrolytic products. Those important primary pyrolytic products such as levoglucosan, hydroxyacetaldehyde and 1-hydroxy-2-propanone were decreased greatly after catalysis. The two microporous zeolites were ef- fective to generate high yields of hydrocarbons, while the three mesoporous materials favored the formation of furan, furfural and other furan compounds, as well as acetic acid.     

同位素内标法对水产品中硝基呋喃代谢物液相色谱-串联质谱法测定

建立了水产品中硝基呋喃类代谢物残留量的同位素内标定量液相色谱-串联质谱法测定。样品经稀盐酸水解,邻硝基苯甲醛衍生,乙酸乙酯提取净化后,用液相色谱-串联质谱法通过正离子扫描多反应监测模式检测,稳定同位素内标定量。本方法的线性范围为1.25～10μg/kg,4种硝基呋喃代谢物的线性相关系数均在0.993 2以上,4种化合物...     

基于新型固相萃取-高效液相色谱法灵敏测定牛奶中的药物残留

利用水热法制备了还原氧化石墨烯-硅胶复合物,将其用于固相萃取柱制备,并与高效液相色谱相结合,建立了牛奶中磺胺类药物测定的新方法.对萃取条件进行了优化,优化条件为:0.1 mL的甲醇-乙酸(V∶V′=1∶1.5)混合液为洗脱剂,75mL的样品溶液.在优化条件下,目标物的线性范围为0.1~100μg/L,检出限为0.027~0.078μg/L(RSN=3).新方法用于牛奶样品分析,加标回收率为88.3%~113.6%.     

An Automatic Solid Phase Extraction and Ultra-Performance Liquid Chromatography Tandem Mass Spectrometry for Determination of Seven Microcystins at Ultra-Trace Levels in Surface Water

A method was developed for the detection of seven microcystins(microcystin-LR, RR, YR, LA, LY, LW and LF) in surface water using automatic solid-phase extraction(A-SPE) coupled with ultra-performance liquid chromatography tandem mass spectrometry(UPLC-MS/MS). The automated solid-phase extraction system was used to extract microcystins(MCs) from water samples. UPLC-MS/MS was used to determine MCs concentrations in just 5 min. Method detection limits were from 0.3 to 0.9 ng/L, microcystin recoveries ranged from 83.8% to 114%, and the relative standard deviation(RSD) varied from 5.6% to 12.5%. This analytical approach was found to be simple, highly sensitive, accurate, which required little manual operation. Additionally, to validate this analytical method, A-SPE+UPLC-MS/MS was applied to characterize the concentration of MCs in Taihu Lake, Wuxi, China.     

液相色谱-串联质谱法测定大鼠血浆中莪术醇的浓度

建立了一个快速、 准确、 灵敏的液相色谱 串联质谱测定鼠血浆中莪术醇的分析方法. 血浆样品经乙腈沉淀蛋白后, 以甲醇-乙腈-10 mmol/L乙酸铵溶液（体积比： 42.5 ∶42.5 ∶15）为流动相, 采用反相色谱柱Nucleosil C¹⁸分离, 通过电喷雾离子化源的四极杆串联质谱仪, 以多反应监测方式检测. 线性范围为2.5~500.0 μg／L, 日间和日内精密度< 4.79%,平均提取回收率为100.7%.     

基于萃取和超高效液相色谱-串联质谱法的贝类抗生素快速测定方法

建立一种简单、快速的超声波萃取–固相萃取净化–超高效液相色谱串联质谱分析方法, 可以同时测定淡水贝类软组织中磺胺类、喹诺酮类、大环内酯类、β-内酰胺类和氨基糖苷类中15种抗生素。采取超声波萃取法, 对贝类体内的抗生素进行萃取, 用固相萃取方法净化提取液, 最后用超高效液相色谱–三重四级杆质谱对目标物进行分析检测。主要比较两种固相萃取柱Oasis HLB和Oasis PRiME HLB对污染物的净化效率, 后者展现出较好的结果。15种抗生素加标回收率实验结果表明: 当加标浓度为50 ng/g时, 回收率为64%~121%, 相对标准偏差为0.5%~19% (n=3); 添加高浓度(100 ng/g)样品时, 回收率为67%~117%, 相对标准偏差为1%~9%(n=3)。方法检测限(LOD)为0.004~0.5 ng/g (干重), 定量限(LOQ)为0.013~1.67 ng/g (干重)。该方法具有回收率高、检测限低的特点。使用该方法对鄱阳湖3个采样点三角帆蚌中的抗生素进行分析, 结果显示, 在15种抗生素中, 有9种均不同程度地检出, 检出频率和浓度最高的是甲氧苄胺嘧啶, 最高浓度达到78.8 ng/g, 其次是奇霉素(41.2 ng/g)和环丙沙星(39.8 ng/g)。     

Near-infrared spectroscopy-based quantification of substrate and aqueous products in wastewater anaerobic fermentation processes

In this study, a Fourier transform near-infrared （FT-NIR） technique was used for process monitoring of anaerobic fermentation. Orthogonal signal correction （OSC） method was used as NIR spectral pre- processing options. Calibration models were established and the validation of the method was per- formed with the sucrose, ethanol and volatile fatty acids （VFAs） contents determined by the anthrone and gas chromatography methods, respectively. Spectral range and the number of internal latent variables were optimized for the best correlation coefficient. Test set validation of sucrose resulted in excellent measurement of prediction performance and the correlation coefficient of determination is 0.930. Similar prediction statistics for individual VFA and total VFA contents were obtained. These re- sults proved that the NIR spectroscopy technology is able to quantify the contents of both volatile fatty acids and sucrose in wastewater anaerobic fermentation process.     

Photodegradation of <Emphasis Type="Italic">N</Emphasis>-nitrosodiethylamine in water with UV irradiation

The direct photolysis of N-nitrosodiethylamine （NDEA） in water with ultraviolet （UV） irradiation was investigated. Results showed that NDEA could be completely degraded under the direct UV irradiation. The effects of the experimental conditions, including the initial concentration of NDEA, humic acid and solution pH, were studied. The degradation products of NDEA were identified and quantified with gas chromatography-mass spectrometry （GC-MS） and high performance liquid chromatography （HPLC）. It was confirmed that methylamine （MA）, dimethylamine （DMA）, ethylamine （EA）, diethylamine （DEA）, NO2^- and NO3^- were the main degradation products. The photolysis degradation mechanism of NDEA was also discussed. As a result of N-N bond fission, NDEA was degraded by direct UV irradiation.     

Detection of infrared photons with a superconductor

A superconductor single photon detector based on NbN nanowire was fabricated using electron beam lithography （EBL） and reactive ion etching （RIE） for infrared photon detection. When biased well below its critical current at 4.2 K, NbN nanowire is very sensitive to the incident photons. Typical telecommunication photons with a wavelength of 1550 nm were detected by this detector. Data analysis indicates the repeating rate of the device with 200 nm NbN nanowire may be up to 100 MHz, and the quantum efficiency is about 0,01% when biased at 0.95/c.     

水样中5种氟喹诺酮的UPLC-QTOF法测定

建立了环丙沙星、恩诺沙星、诺氟沙星、氧氟沙星和培氟沙星等5种氟喹诺酮类抗生素(FQs)的超高效液相色谱-四极杆飞行时间质谱(UPLC-QTOF)定量分析方法.样品经Waters ACUITY UPLC BEH C18色谱柱分离,含0.1％甲酸(体积分数)的水溶液-甲醇为流动相进行梯度洗脱,电喷雾串联飞行时间质谱正离子模...     

液-质联用测定鱼体内甲基磺草酮的残留量

为了检测鱼体内甲基磺草酮的残留量,建立液相色谱串联质谱的方法测定甲基磺草酮。结果表明:在0.5~100μg/L浓度范围内,线性相关系数(r)为0.998 6。当添加质量分数为0.1~10μg/g时,甲基磺草酮在鱼体内的平均回收率为80.0%~99.3%,RSD为3.4%~8.4%。该方法的最小检出量为5.0×10-12g,鱼体内的最低检测质量分数(LOQ)为0.1μg/g。该方法操作简单可靠,准确度、精密度及其灵敏度均满足农药残留分析的要求,可用于鱼体内甲基磺草酮残留量的测定。     

基质固相分散-牛奶、蜂蜜中喹诺酮的多残留分析

以C18为基质固相分散剂,采用基质固相分散技术进行样品前处理,建立了基质固相萃取-液相色谱法分析牛奶和蜂蜜中4种氟喹诺酮的方法,并对基质固相萃取条件和色谱分离条件进行了探讨和优化.在2.5 ng/g和10.0 ng/g 添加水平,4种氟喹诺酮类药物的平均加标回收率为81.9%～111.6%,相对标准偏差<7%.检出限为 0.05 μg/L.     

头发中内源性氢化可的松的高效液相色谱/串联质谱检测

基于高效液相色谱/串联质谱(HPLC/MS/MS)建立了一种检测头发中内源性氢化可的松含量的方法,并与高效液相色谱/荧光法(HPLC/FLU)的测定结果进行比较.头发样品(50 mg)经过清洗与研磨、甲醇提取和C18固相萃取后,在电喷雾(ESI)负离子模式和多反应监测(MRM)方式下进行定性,以外标法进行定量.方法的定...     

A novel heteroseneous reaction for generating gaseous nitrous acid

The short-lived reactive specimen nitrous acid HONO was generated in the gas phase by the heterogeneous reaction of gaseous HCl with AgNO2 which can generate higher concentration of HONO than other methods. We investigated the process from generation to dissociation in the gas phase under different controlled temperatures, and discussed the ionization and reaction on the solid surface by combination of the photoelectron spectroscopy and photoionization mass spectroscopy （PES-PIMS） and in situ diffuse reflectance infrared Fourier transform spectroscopy （DRIFTS）.     

Male panda （Ailuropoda melanoleuca） urine contains kinship information

Chemical communication plays an important role in kin selection and mate choice in mammals. The covariance of odor-genes of rodents has been documented and kinship odor has been proposed and termed, yet little is known of the relationship between genetic relatedness and chemical composition of kinship odors. Giant pandas （Ailuropoda melanoleuca） rely substantially on chemical communication to mediate their social interactions. To examine the relationship between genetic relatedness and compounds in the urine/anogenital gland secretions, we compared the similarities between genetic relatedness and the chemical profiles of anogenital gland secretions and urine via lineage construction and GC-MS （gas chromatography and mass spectrometry）. We found that information about kinship odors was present only in the urine of male adults in the mating season but absent in the non-mating season. Adult females and all sub-adults did not have such kinship odors in either mating or non-mating season. Therefore, kinship odor in the panda was contingent on age, sex, and season. This is the first report about the condition-dependent expression of kinship odor, which may have a significant implication in the practice of panda conservation in relation to chemical communication and sexual selection.     

高效液相色谱法测定饲料及乳制品中的三聚氰胺

高效液相色谱法作为一种快速、高效的分离分析技术,已应用于许多领域。分析了12种液相色谱法在测定饲料及乳制品中三聚氰胺各项指标,并对不同方法的提取溶剂、沉淀剂、色谱柱和流动相进行归纳总结。     

Arctic dipole anomaly and summer rainfall in Northeast China

A dipole structure anomaly in summer Arctic atmospheric variability is identified in this study, which is characterized by the second mode of empirical orthogonal function （EOF） analysis of summer monthly mean sea level pressure （SLP） north of 70°N, accounting for 12.94% of the variance. The dipole anomaly shows a quasi-barotropic structure with opposite anomalous centers over the Canadian Arctic and the Beaufort Sea and between the Kara Sea and the Laptev Sea. The dipole anomaly reflects alternating variations in location of the polar vortex between the western and eastern Arctic regions. The positive phase of the dipole anomaly corresponds to the center of the polar vortex over the western Arctic, leading to an increase in summer mean rainfall in Northeast China. The dipole anomaly has a predominant 6-year periodicity, and shows interdecadal variations in recent decades.