叶绿素荧光技术在海草生态学研究中的应用

本文综述了近10 a来国外关于叶绿素荧光技术在海草生态学研究中应用的概况和进展,主要从以下两方面进行论述:(1)叶绿素荧光技术在海草各种环境因子胁迫(如光照、温度、盐度、藻类竞争、除草剂、重金属和毒性有机物等)测试下的应用;(2)海草叶片荧光特性的差异性对叶绿素荧光技术应用的影响以及荧光参数应用层面的拓展.最后对未来的研究提出了建议和展望,为我国在这方面的研究提供相关的依据.     

绿色荧光蛋白标记的大肠杆菌海水中稳定性研究

用绿色荧光蛋白基因( GFP) 标记大肠杆菌K12(K12GFP),检测其在海水中的存活及稳定性.研究结果表明,K12与K12GFP微生物学特性差异不显著,而且两者在高压灭菌海水中的存活曲线也基本一致,说明K12GFP可为进一步研究K12在自然海水中的生态变化提供可靠依据.在高压灭菌海水中,K12GFP存活28 d之久,该菌密度随时间缓慢下降;在过滤海水中,K12GFP存活7 ,该菌密度从107CFU/mL降到102CFU/mL.表明海水的营养成分会对其存活产生较大影响.     

Early stage toxicity of excess copper to photosystem II of Chlorella pyrenoidosa-OJIP chlorophyll a fluorescence analysis

Acute toxicity of excess Cu on the photosynthetic performance of Chlorella pyrenoidosa was examined by using chlorophyll a fluorescence transients and JIP-test after exposure to elevated Cu concentrations for a short period of time.High Cu concentration resulted in a significant suppression in photosynthesis and respiration.The absorption flux (ABS/RC) per PSⅡ reaction center increased with increasing Cu concentration,but the electron transport flux (ET_0/RC) decreased.Excess Cu had an insignificant effect on the trapping flux (TR_0/RC).The decline in the efficiency with which a trapped exciton can move an electron into the electron transport chain further than QA- (ψ_o),the maximal quantum yield of primary photochemistry (φP_o),and the quantum yield of electron transport (φE_o) were also observed.The amount of active PSⅡ reaction centers per excited cross section (RC/CS) was also in consistency with the change of photosynthesis when cells were exposed to excess Cu concentration.JIP-test parameters had a good linear relationship with photosynthetic O_2 evolution.These results suggested that the decrease of photosynthesis in exposure to excess Cu may be a result of the inactivation of PSⅡ reaction centers and inhibition of electron transport in the acceptor side.     

Application of ultrasonic to speciation analysis of heavy metals in soil

In order to reduce the operation time and improve the extraction efficiency, ultrasonic energy by means of ultrasonic bath was used to the modified Tessier sequential extraction for speciation analysis of heavy metals in soil. Extractable contents of Cu, Fe, Mn, Ni,Pb and Zn were measured by atomic absorption spectroscopy(hAS). The merit of the ultrasonic extraction (UE) applied to the modified Tessier method is not only that the operation time for the first 4 fractions was reduced from ca. 18 h to 8 h, comparing with conventional extraction(CE), but also the extraction efficiency was higher. The results for both of UE and CE were consistent. The extractable Cu, Ni and Zn in the sample No. 1 were mainly associated with the third fraction (Fe-Mn oxides fraction), and fourth fraction (organic matter fraction) in the sample No.2. The extractable Fe and Mn were all mainly associated with the third fraction, and Pb the fourth fraction in both of the samples. The effects of concentration of hydroxylamine chloride on the capability for the extraction of studied metals were also studied.     

Concentration effect of trace metals in Jordanian patients of urinary calculi

Due to the increase in the number of urinary calculi disease cases in Jordan, stone samples were collected from patients from various Jordanian hospitals (Princes Basma (PBH), King Abdullah University (KAUH), Al-Basheer (ABH) and Al-Mafraq (AMH)). This study concentrates on the effect of trace metals in patients of urinary calculi. Trace metals were detected in 110 urinary calculi samples using X-ray fluorescence (XRF) and atomic absorption spectroscopy (AAS) techniques. Of the calculi examined, 21 were pure calcium oxalate (CaOax), 29 were mixed calcium oxalate/uric acid, 23 were mixed calcium oxalate/phosphate (apatite), 25 were phosphate calculi (apatite/struvite), five were mixed calcium oxalate monohydrate/struvite, four were urate calculi (mixed ammonium acid urate/sodium acid urate) and three were pure cystine calculi. The concentration measurement of Ca and other trace metals levels has been found useful in understanding the mechanism of stone formation and in evaluating pathological factors. It has been found that Ca is the main constituent of the urinary calculi, especially those stones composed of calcium oxalate and calcium phosphate. The concentration of most of the trace metals that were analyzed was (Ca = 48.18, Na = 1.56, K = 0.9, Mg = 3.08, Fe = 1.17, Al = 0.49, Zn = 0.7, Cu = 0.19, Mn = 0.029, P = 10.35, S = 1.88, Sr = 0.306, Mo = 0.2, Cr = 0.146, Co = 0.05, Ni = 0.014)%. In conclusion, metals concentration in Jordanian patient’s urinary calculi samples was higher than its equivalents of other patients’. It has been noted that there is no concentration of toxic trace elements (like Li, V, Pb, Cd, and As). Some heavy metals, however, were detected Mo, Cr, Co and Ni as traces. P and S ions are present in few calculi stones as traces.     

氢化物发生原子荧光法测定钻井废水中的铅

目前测定铅的分析方法主要有分光光度法、阳极溶出伏安法、示波极谱法、原子吸收法等。针对比色法灵敏度低,试剂不稳定;电化学法干扰严重;而原子吸收法,线性范围窄,样品用量大等问题,江苏油田采用氢化物发生原子荧光法测定钻井废水中的铅。样品经HNO3-HClO4消解,3％～4％KBH4还原,以0.8％～1.5％的HCl为介质,加入10％K3Fe(CN)6和2％H2C2O4基体改进剂,用原子荧光法连续测定钻井废水中的铅。铅的检测限为0.61ng/mL,回收率为87.4％～146％,变异系数＜4.2％。该方法操作简单,灵敏度高。     

基于光谱技术的土壤多参数快速检测进展与展望

传统的土壤采样和实验室分析方法往往工作量大、前处理复杂、测定周期长、时效差、费用高,因此,迫切需要寻找快速、准确的土壤多参数检测方法,以实现多尺度土壤属性数据的快速获取与更新。系统梳理了便携式X射线荧光光谱(PXRF)、可见光-近红外反射光谱(Vis-NIR)、激光诱导击穿光谱(LIBS)和电弧发射光谱(AES)等光谱技术的原理、特点以及在土壤多参数快速检测中的应用及其研究进展。提出,未来在提高现有土壤多参数光谱检测精度和适用性的基础上,应结合ICP-MS等传统实验室方法,综合应用多种光谱技术以及化学计量学、现代信息技术和空间分析技术等,实现区域多种土壤属性的快速获取与实时监测,以满足我国当前土壤多参数、高精度快速检测及土壤质量精细化管理的需要。     

Validation of QuEChERS method for the determination of some pesticide residues in two apple varieties

This study was undertaken to validate the “quick, easy, cheap, effective, rugged and safe” (QuEChERS) method using Golden Delicious and Starking Delicious apple matrices spiked at 0.1 maximum residue limit (MRL), 1.0 MRL and 10 MRL levels of the four pesticides (chlorpyrifos, dimethoate, indoxacarb and imidacloprid). For the extraction and cleanup, original QuEChERS method was followed, then the samples were subjected to liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS) for chromatographic analyses. According to t test, matrix effect was not significant for chlorpyrifos in both sample matrices, but it was significant for dimethoate, indoxacarb and imidacloprid in both sample matrices. Thus, matrix-matched calibration (MC) was used to compensate matrix effect and quantifications were carried out by using MC. The overall recovery of the method was 90.15% with a relative standard deviation of 13.27% (n = 330). Estimated method detection limit of analytes blew the MRLs. Some other parameters of the method validation, such as recovery, precision, accuracy and linearity were found to be within the required ranges.     

北京市垃圾填埋场地下水中砷、汞含量分析

生活垃圾的处置一直以填埋为主,垃圾填埋承载着巨大的环境压力,尤其是垃圾填埋产生的渗滤液会对地下水造成砷、汞污染。为了解北京市生活垃圾填埋场地下水砷、汞污染水平,在北京市5座生活垃圾填埋场布设采样点,采集36个地下水样品,采用氢化物发生-原子荧光法,分析了地下水砷、汞含量特征。结果表明,36个地下水样品砷浓度范围0.41~4.82μg/L,汞浓度范围0.024~0.121μg/L,北京市典型垃圾填埋场地下水样品不存在砷、汞污染问题。     

Development,validation and application of a method to analyze phenols in water samples by solid phase micro extraction-gas chromatography-flame ionization detector

In this work the development, validation and application of method using Solid Phase Microexctration (SPME) for the analyses of five pollutants (phenol, 2-nitrophenol, 2,4-dimethylphenol, 2,4-dichlorophenol and 4-chloro, 3-methyl phenol) in supplying water, using gas chromatography (GC) with flame ionization detector (FID) is described. The optimal conditions obtained for SPME were: fiber type: Poliacrylate (PA); extraction time: 40 minutes; extraction temperature: 70°C; amount of salt added to sample (NaCl): 15%; desorption temperature: 8 minutes. The parameters studied in the method validation were: limit of detection (0.3 and 3.5 μ g.L^{? 1}); precision, measured by the variation coefficient (between 2.1 and 8.8%); calibration curve and linearity, by using the external standardization method (between 1 and 50 50 μ g.L^{? 1}). After the methodology development, samples of water collected in Atibaia River (São Paulo - Brazil) were analyzed, using the optimized methodology. Three water samples collected in the rain season showed a peak with retention time close to 4-chloro, 3 methyl phenol further analyzed by Gas Chromatography-Mass Spectrometry for the identity confirmation. In spite of the fact that none target compounds were found in the river water samples analyzed, the presence of two phenols different from those investigated (p-terc butyl phenol; butylated hydroxytoluene) were detected. These results together with the results of the limit of detection (that showed to be lower than the maximum concentration of phenols demanded by different environment control agencies), and the results of the validation, indicate the applicability of this method for the analysis of selected phenols in river water samples.