离子色谱-电感耦合等离子体质谱联用测定海水中的IO3^-和I^-

研究了离子色谱-电感耦合等离子体质谱（IC-ICPMS）联用技术直接进样测定海水中IO3^-和I^-的方法．采用IonPacAG23离子色谱保护柱分离IO3^-和I^-,以浓度4．0mmol／dm3的KOH为流动相,流量为1．0cm3／min,每个样品的分析时间为2．5min．采用2．5×10^-3cm^3的进样量,IO3^-和I^-的检出限分别达到0．6和0．4nmol／dm2,可满足海水中碘形态的定量分析．该方法的IO3^-和I^-浓度范围在2．0nmol／dm3～2．0μmol／dm3．     

Study on the analysis and distribution of dimethylsulfoxide in the Jiaozhou Bay

A chemoreduction-purge-and-trap gas chromatographic method has been developed for the determination of trace dimethylsulfoxide (DMSO) in seawater. In the analysis procedure, DMSO was first reduced to dimethylsufide (DMS) by sodium borohydride and then the produced DMS was analyzed using the purge-and-trap technique coupled with gas chromatographic separation and flame photometric detection. Under the optimum conditions, 97% DMSO was reduced in the standard solution samples with a standard deviation of 5% (n=5). The detection limit of DMSO was 2.7 pmol of sulfur, corresponding to a concentration of 0.75 nmol/L for a 40 ml sample. This method was applied to determine the dissolved DMSO (DMSOd) and particulate DMSO (DMSOp) concentrations in the surface seawater of the Jiaozhou Bay, and the results showed that the DMSOd and DMSOp concentrations varied from 16.8 to 921.1 nmol/L (mean:165.2 nmol/L) and from 8.0 to 162.4 nmol/L (mean:57.7 nmol/L), respectively. The high concentrations of DMSOp were generally found in productive regions. Consequently, a significant correlation was found between the concentrations of DMSOp and chlorophyll a, suggesting that phytoplankton biomass might play an important role in controlling the distribution of DMSOp in the bay. Moreover, in the study area, the concentrations of DMSOd were significantly correlated with the levels of DMS, implying that the production of DMSOd is mainly via photochemical and biological oxidation of DMS.     

利用核酸适配体的竞争置换作用检测溶藻弧菌(Vibrio alginolyticus)

溶藻弧菌(Vibrio alginolyticus)是水产养殖中致病性较强的一种条件致病菌,为更灵敏、高效地对其进行检测,研发出一种基于核酸适配体竞争置换作用的检测方法。首先设计并制备出磁珠-核酸适配体-荧光报告探针的检测复合物(MAP检测复合物),然后利用溶藻弧菌与其核酸适配体有较好的亲和特异性,在对样品进行检测时,样品中的溶藻弧菌就会竞争MAP检测复合物中的核酸适配体,从而置换出与该核酸适配体结合的荧光报告探针,再通过检测置换出的报告探针的荧光强度来表征溶藻弧菌的浓度,从而实现对溶藻弧菌的定量检测。结果表明,该方法对溶藻弧菌的检测限可达到1CFU/mL,与嗜水气单胞菌(Aeromonas hydrophila)、迟钝爱德华氏菌(Edwardsiella tarda)、哈维氏弧菌(Vibrio harveyi)、大肠杆菌(Escherichia coli)等水产养殖中的常见致病微生物没有交叉反应,并在1~20、20~100和100~1000 CFU/mL范围内都表现出较好的线性关系。另外还对MAP检测复合物的制备条件进行了优化,较为理想的制备条件为:100nmol/L核酸适配体与100nmol/L荧光报告探针按体积比1︰1混合结合30 min,制备出50 nmol/L的核酸适配体-荧光报告探针复合物,然后该复合物再与25μg/mL的磁珠按体积比1︰1混合结合60 min,制备出相应的MAP检测复合物。利用核酸适配体的竞争置换作用检测溶藻弧菌有较好的灵敏度和特异性,展现了较好的应用前景。     

化学发光法测定天然水体中低浓度硝酸盐和亚硝酸盐的含量

传统分光光度法测定硝酸盐和亚硝酸盐含量时检测限较高,无法测定部分海洋表层及寡营养盐海域低含量的硝酸盐和亚硝酸盐浓度,急需采用一种新的测定低浓度硝酸盐和亚硝酸盐的方法.化学发光法用于测定水体中硝酸盐和亚硝酸盐含量,具有灵敏度高、检测限低、样品用量少,不受悬浮颗粒物、有色物质影响及样品批量测定等优点.本文通过探索载气流速、...     

锑原位掺杂SiO2@PDA-Sb复合材料修饰电极用于海水中Zn离子检测

本研究提出了一种用于检测海水中锌离子(Zn²⁺)含量的电化学检测方法。该方法首先应用水热法合成SiO₂@PDA-Sb复合材料,然后将该复合材料修饰到玻碳电极上制备SiO₂@PDA-Sb-Nafion/GCE,利用差分脉冲阳极溶出伏安法(DPASV)对珠江口海水水样中Zn²⁺进行测定。研究结果表明,Zn²⁺在SiO₂@PDA-Sb-Nafion/GCE上具有较强的溶出峰。在最优条件下,SiO₂@PDA-Sb-Nafion/GCE对Zn²⁺浓度在1～1 000 nmol/L范围内可实现灵敏、准确的检测,Zn²⁺的检测出限为0.71 nmol/L。加标回收率实验显示Zn²⁺加标回收率为93.19%～100.12%,表明该方法可应用于现场海水样品Zn²⁺测定。本方法具有电极制作简单、稳定性和抗干扰性良好,能够提高现有测定方法的检测限和精确度,在现场海水检测...     

Flow injection analysis of nanomolar level orthophosphate in seawater with solid phase enrichment and colorimetric detection

Phosphomolybdenum blue (PMB) paired with cetyltrimethylammonium bromide (CTAB) can be extracted using a solid phase extraction technique on C18 sorbent. Based on this, a novel on-line solid phase extraction method coupled with flow injection (FI) analysis and colorimetric detection has been established to determine nanomolar level orthophosphate in seawater. A stopped flow technique was employed to assure the complete formation of the PMB–CTAB compound, which was sequentially extracted on an in-line Sep-Pak C₁₈ cartridge. The adsorbed PMB–CTAB can be rapidly eluted by 0.56 mol/L H₂SO₄ in ethanol, and determined with a spectrophotometer at 700 nm. Experimental parameters, including reaction temperature, sample loading flow rate, stopped time and eluting flow rate, were optimized throughout the experiments based on univariate experimental design. The results show that reaction temperature and stopped time were the major factors affecting the formation of PMB–CTAB. Silicate concentration up to 5000 times higher than that of orthophosphate would not interfere with the determination of orthophosphate. Using artificial seawater with salinity of 35 as a matrix under the optimized conditions, the standard curve shows a linear range between 3.2 and 48.5 nmol/L, and the recovery and the detection limit of the proposed method are 96.4% and 1.57 nmol/L, respectively. The relative standard deviation (RSD) (n = 8), which was determined daily for 8 days, was 4.52% for the artificial seawater at a concentration of 32.4 nmol/L orthophosphate. Two typical seawater samples were analyzed using both the proposed method and the MAGnesium hydroxide-Induced Coprecipitation (MAGIC) method. The results of the two methods show no significant difference using the t test. Compared to the MAGIC method, the proposed method has the advantage of being more sensitive, faster, sample saving and easy for on-line analysis.     

阴极溶出伏安法测量海水中溶解态铁

使用阴极溶出伏安法,利用2,3-二羟基苯丙氨酸(DHN)可以与Fe(Ⅲ)结合生成配合物,而BrO3-的加入可以催化该电化学反应的性质,系统研究了海水中溶解态Fe(Ⅲ)的最佳分析条件。结果表明,体系中添加20.0μmol/L DHN即可达到分析要求;添加BrO3-可以使溶出电流线性增大,选择的最终浓度为20.0mmol/L。当沉积电位为-0.20V,扫描速率为50.0mV/s,沉积时间为90s时,即可达到低铁海水的分析要求,在此条件下检测限为0.011nmol/L。紫外消解可以使测量灵敏度比未消解时提高13倍。用此方法测量得到的太平洋某处(158°15′E,22°23′N)海水表层水浓度为0.45nmol/L,75m处浓度为0.14nmol/L,1 500m处浓度为0.86nmol/L。     

Studies on the determination of inorganic iodine in seawater

Existing methods for the determination of the various forms of iodine present in seawater are laborious or unwieldy in use. This paper describes modified forms of the iodate and total iodine methods described by Barkley and Thompson (1960), a spectrophotometric procedure for iodate determination derived from Johannesson's (1958) work, and an automatic method for total iodine determination. Procedures for iodate and total-iodine determination which are suitable for use aboard ship, are recommended. Both procedures for iodate determination returned a standard deviation close to 0.5 μg/l when several replicate samples of a seawater containing approximately 30 μg/l of iodate-iodine were analysed. The automatic method for total iodine determination yielded a standard deviation of 0.8 μg/l by the repeated analysis of a seawater containing a total of approximately 50 μg/l of iodine. Suitable methods for the filtration and storage of seawater are also described.     

Sequential injection analysis of nanomolar soluble reactive phosphorus in seawater with HLB solid phase extraction

A cartridge of solid phase extraction (SPE), hydrophilic–lipophilic balance (HLB), has been used to enrich phosphomolybdenum blue (PMB) from water samples without any other additives. Based on this, the previous on-line SPE method established for the determination of nanomolar soluble reactive phosphorus (SRP) in seawater has been greatly improved. Cetyltrimethylammonium bromide (CTAB), the cationic surfactant needed for the formation of the PMB-CTAB paired compound that could be extracted on a Sep-Pak C18 cartridge using the previous method [Liang, Y., Yuan, D.X., Li, Q.L., Lin, Q.M., 2007. Flow injection analysis of nanomolar level orthophosphate in seawater with solid phase enrichment and colorimetric detection. Marine Chemistry 103, 122–130.], was not necessary. Thus the longer time and higher temperature required for the complete formation of the PMB-CTAB compound were no longer needed. In addition, with application of the sequential injection analysis technique the proposed method showed the advantages of being much faster, simpler, sample and reagent saving, as well as more convenient in operation. The PMB compound formed under room temperature was efficiently extracted on an in-line HLB cartridge, rapidly eluted by 0.15 mol/L NaOH solution, and finally determined with a laboratory-made spectrophotometer at 740 nm. Experimental parameters, including the volume of reagents added, sample loading flow rate, and eluting flow rate, were optimized. Time and temperature for the PMB reaction, and salinity effect were also studied, and these were found to have no severe effect on the detection. With variation of sample loading time at a fixed flow rate, a broadened determination range of 3.4 to 1134 nmol/L phosphate could be obtained. The recovery and the method detection limit of the proposed method were found to be 94.4% and 1.4 nmol/L, respectively. The relative standard deviation (n = 7) was 2.50% for the sample at a concentration of 31 nmol/L phosphate. Two typical seawater samples were analyzed with both the proposed method and the magnesium hydroxide-induced coprecipitation method and, using the t-test, the results of the two methods showed no significant difference.     

离子迁移谱现场观测渤海和北黄海二甲基硫的研究

渤海、黄海是高产二甲基硫(Dimethyl Sulfide,DMS)的大陆架海区.该海区DMS的现场调查研究有助于准确评估海洋DMS释放量及其对全球气候变化的负反馈作用.目前,无论是基于模型还是直接测量法的通量估算均以表层海水或低层大气DMS浓度为基础,因此,先进的检测技术对其通量估算的准确度具有决定性作用.气相色谱法...     

Methane in Water and Bottom Sediments in Three Sections in the Kara and Laptev Seas

The methane content in water and bottom sediments was measured in vertical sections: Lena River Delta–continental slope (the Laptev Sea), Taimyr Peninsula–Voronin Trough, and along the Novaya Zemlya Archipelago. The methane concentrations varied from 2.5 to 70 nmol/L and from 590 to 2600 nmol/L in the water column and sediments, respectively. Most of the surface water samples showed oversaturation in methane (up to 19-fold, fourfold on average), which determined the water–atmosphere direction of methane fluxes, which amounted to 1–400 mol/km² day (52 mol/km² day on average).     

海洋沉积物孔隙水中痕量金属元素的测试分析方法

孔隙水是沉积物-海水界面链接沉积物颗粒和上覆水体的一个重要过渡相态,针对其研究可更好地了解痕量金属在固-液界面的早期成岩过程。近年来,针对孔隙水中痕量元素研究的方法较为匮乏,为此建立了一种分析测定海洋沉积物孔隙水中7种痕量金属元素(Mn、Cu、Zn、Ni、Cd、Co、Pb)的方法,该方法使用Nobias PA1树脂进行富集分离,再使用电感耦合等离子体质谱(ICP-MS)进行测试,可针对孔隙水中的痕量金属元素进行准确分析。通过实验结果发现该方法最优实验条件为: Nobias PA1树脂富集时的pH值为5.5~6.0,洗脱酸浓度为1.3 mol/L硝酸,体积为1 mL。同时,样品需进行紫外消解4 h以上以分解有机络合物,该消解步骤对Cu和Co这两种元素尤其重要。该方法通过加标回收获得Mn、Cu、Ni、Co和Pb的回收率在92%~100%, Zn和Cd的回收率分别为72%和82%; Mn、Cu、Zn、Ni的方法检出限范围为0.03~0.53 nmol/L, Cd、Co、Pb的方法检出限范围为2.66×10^-3~8.60×10^-3 nmol/L,满足孔隙水中痕量金属浓度的测试需求。同时,根据检出限计算的结果显示,孔隙水样品只需1 mL,即可应用该方法进行测试。应用该方法测试了一根采集于北黄海中部沉积物短柱的孔隙水样品,测试结果显示其垂相分布合理、较符合早期成岩过程规律。此研究为分析海洋沉积物孔隙水中痕量金属元素提供了一种准确而简便的方法。     

海洋药用生物系列HPLC化学指纹图谱研究 Ⅱ.三斑海马HPLC化学指纹图谱研究

采用高效液相色谱(HPLC)法建立三斑海马的参考指纹图谱.运用DAD-Agilent 1100高效液相色谱仪,色谱条件:Agilent Zorbax XDB C18色谱柱(4.6 mm×250 mm;5.0 μm),乙腈-0.1%磷酸水流动相梯度洗脱,流速1.0 mL·min-1,检测波长200 nm,参比波长360 nm,柱温30 ℃.结果显示建立的指纹图谱包含11个共有峰,方法的精密度、重现性和稳定性试验RSD值均小于5.0%.研究表明所建立的三斑海马的参考指纹图谱可用于药材的真伪鉴别.     

电解富集-液体闪烁计数法测量北极海水中氚活度

A method of measuring the tritium in seawater based on electrolytic enrichment and ultra-low background liquid scintillation counting techniques was established. The different factors influencing the detection limit were studied, including the counting time, the electrolytic volume of the seawater samples, the selection of background water, scintillation solution and their ratio. After optimizing the parameters and electrolyzing 350 mL volume of samples, the detection limit of the method was as low as 0.10 Bq/L. In order to test the optimization of system for this method, of the 84 seawater samples collected from the Arctic Ocean we measured, 92% were above the detection limit(the activity of this samples ranged from 0.10 Bq/L to 1.44 Bq/L with an average of(0.30±0.24) Bq/L).In future research, if we need to accurately measure the tritium activity in samples, the volume of the electrolytic samples will be increased to further reduce the minimum detectable activity.     

Development and validation of a TaqManTM fluorescent quantitative real-time PCR assay for the rapid detection of Edwardsiella tarda

Edwardsiella tarda is one of the most important emerging pathogens in the global aquaculture industries. As such, an accurate diagnosis and quantitative analytical methods are urgently needed for this bacterium. In this study, primers and a TaqMan probe specific to the conservative sequences of the 16S rRNA gene of E. tarda were designed. The concentration of primers and TaqMan probe were optimized to 200 nmol/L and 120 nmol/L, respectively. The detection sensitivity of the FQ-PCR assay was determined to be as low as five copies of the target sequence per reaction using the pGEM-16S rDNA recombinant plasmid as a template, which was 100 times more sensitive than conventional PCR. A standard curve by plotting the threshold cycle values （y） against the common logarithmic copies （log₁0 n_c as x; n_c is copy number） of pGEM-16S rDNA was generated. The results of intra-and inter-assay variability tests demonstrate that the established FQ-PCR method was highly reproducible. The assay was specific for E. tarda as it showed that there was no cross-reactivity to eight additional bacterial pathogen strains in aquaculture. Thus, the FQ-PCR assay has the potential for diagnostic purposes and for other applications, especially for the rapid detection and quantification of low-grade E. tarda infections.     

Analysis of molybdenum,tungsten, and vanadium in surface water of the Atlantic Ocean using solid phase extraction with 8-hydroxyquinoline and ICP MS determination

An analytical technique is proposed to determine ultratrace concentrations of Mo, V, and W found in seawater using mass spectrometry with inductively coupled plasma (ICP MS) after preliminary concentration by solid-phase extraction of metal complexes with 8-hydroxyquinoline (8-HQ) on C18 octadecyl silica. The technique utilizes 150 mL of a water sample. A preconcentration factor 50 is obtained. The detection limits are 0.25 nmol/kg, 0.041 nmol/kg, and 5 pmol/kg for Mo, V, and W, respectively. Dissolved Mo, V, and Wconcentrations in surface seawater from Atlantic Ocean transect were determined. The concentrations ranges along the transect were: 91–108 nmol/kg for Mo, 28–35 nmol/kg for V, and 55–75 pmol/kg for W. The Mo/W ratio varied from 1300 to 1800.     

Reduction of iodate in seawater during Arabian Sea shipboard incubations and in laboratory cultures of the marine bacterium Shewanella putrefaciens strain MR-4

Shipboard incubations from the US JGOFS cruise to the Arabian Sea (TN045) March, 1995 showed evidence of iodate reduction in 0.45 μ (Gelman Supor membrane) filtered seawater samples collected from intermediate depths (200–600 m) within the oxygen minimum zone (OMZ). Inorganic chemical reduction of iodate in these samples was ruled out as no free sulfide was measurable and concentrations of ammonia and nitrite were found to be less than 5 μM. To examine whether the reduction of iodate observed at sea could have been the result of bacterial metabolism, reduction of iodate (IO₃⁻) to iodide (I⁻) by Shewanella putrefaciens strain MR-4 was studied in artificial seawater using electrochemical methods. MR-4 is a ubiquitous marine bacterium which may be of considerable importance when considering redox zonation in the water column because it is a facultative anaerobe and may switch amongst a suite of electron acceptors to support metabolism. In all experiments MR-4 reduced all iodate to iodide. The rate of formation of [I⁻]in the culture followed pseudo-first order kinetics. This is the first report of the marine bacterial reduction of iodate where the concentrations of iodide and iodate were measured directly. Our results may help to explain the depth distribution of iodine speciation reported in productive waters like the Arabian Sea and for the first time couple iodine speciation with bacterial productivity in the ocean.     

A comparative study of three methods for the determination of iodate in seawater

A comparative study of three methods for the determination of iodate-iodine in seawater is described. In one method the iodate is determined polarographically while in the others the iodate is determined colorimetrically as iodonium ions. In one of the colorimetric methods each sample is pre-treated with excess iodine-water in an attempt to eliminate suspected interference from naturally occurring reducing agents. The tests were conducted on a selection of open-ocean and near-shore waters with iodate concentrations ranging from 0 to 60 μg 1^?1-I. The tests indicated that the polarographic method and the colorimetric method without iodine-water give the more reliable measurement of iodate concentration. Also, the method with iodine water was found to be in error especially at low iodate concentrations. Reducing agents, if present, were found not to interfere significantly.     

Determination of ammonium regeneration rates in the oligotrophic ocean by gas chromatography/mass spectrometry

A method has been developed for the determination of ammonium concentration and isotopic enrichment in seawater samples at the low nanomolar range (10–100 nmol/kg). It is based on the reaction of phenol/hypochlorite with ammonium to form indophenol, with subsequent solid phase extraction, derivatisation and analysis by Gas Chromatography Mass Spectrometry. The precision of the method was maximised by incorporating a deuterated indophenol internal standard. A system was developed which generated seawater with extremely low ammonium concentrations thus matching sample and standard matrices for quantitative analysis. Data are presented from a study of ammonium regeneration rates at three stations in the oligotrophic North–East Atlantic where ambient ammonium concentrations were < 21 nmol/kg. Results suggested that ammonium availability for phytoplankton was limited by the rate of ammonium regeneration. Efficient ammonium assimilation contributed to the very low ambient ammonium concentrations measured at these stations. The study highlights the need for the accurate determination of ammonium regeneration rates in studies of new production, particularly in extreme oligotrophic conditions. If not corrected for isotope dilution, f-ratio estimates may be overestimated by 10.7–13.7%.     

海水中丙烯酸的高效液相色谱法建立及应用

建立了一种测定海水介质中丙烯酸的高效液相色谱法。采用耐纯水相和较低pH的Agilent SB-Aq-C18柱(100 mm×4.6 mm i.d.,5 μm), 0.35%磷酸溶液(pH=2)为流动相,使用紫外检测器,检测波长为210 nm,外标法定量测定。丙烯酸的保留时间在14.2~ 14.9 min,方法的检出限为4 nmol/dm3(S/N=3),在0.01~10 μmol/dm3的范围内均有良好的线性关系,相关系数可达0.999 6,加标回收率为95.4%~98.1%,相对标准偏差为1.3%~1.6%(1.04~2.32 μmol/dm3)。采用0.2 μm滤膜重力过滤冷藏的办法来保存海水丙烯酸样品。检测出2011年5月份青岛近海海水中丙烯酸的平均浓度为(0.101±0.069) μmol/dm3;海洋微藻球形棕囊藻在整个生长周期内培养体系中丙烯酸的浓度为0.339~2.219 μmol/dm3。