共查询到19条相似文献，搜索用时 406 毫秒
1.
研究用气相色谱测定海水及天然水中微量碘离子含量的快速分析方法，确定了最佳条件。水样经酸化后，用Ｋ２Ｃｒ２Ｏ７将碘离子氧化成碘，再与丁酮反应的１０ｍｉｎ，生成磺代丁酮，用环己烷萃取后，用气相色谱仪的电子捕获检测器测定其含量。于１９９１年６月，用此法测定青岛胶州湾沿岸海水及某些河口水样，证明该方法简便、快速。 相似文献
2.
胶州湾近岩水中碘离子的气相色谱测定 总被引：1，自引：0，他引：1
介绍了用气相色谱法测定海水中微量碘离子的一种新方法。水样经硫酸酸化、重铬酸钾氧化后产生游离碘，与丁酮作用生成碘代丁酮，再经环已烷萃取后用ＥＣＤ检测器检测其含量。此方法操作步骤简单，适于大批量水样的快速测定。 相似文献
3.
本文提出用碘化钾—甲异丁酮(MIBK)—双硫腙萃取分光光度法来测定海水及海洋底质中的镉。实验证明,海水中的镉经过阴离子交换富集分离,底质中的镉用甘油碱法沉淀处理后,再用碘化钾——甲异丁酮萃取,双硫腙比色测定的方法有着萃取效率高,分离效果和重现性好,操作步骤较简便,避免使用剧毒的氰化钾等优点。本法不需要使用贵重的仪器和药品,是一个便于普及的方法。测定结果经与原子吸收分光光度法、极谱法对比是满意的。此外,还探讨了一些条件实验。 本法用于水样的测定,回收率可达80％以上,最低检出浓度,如取5升水样,可检出0.02微克/升。用于底质的测定,回收率可达90％以上,最低检出浓度为0.1微克。 相似文献
4.
三、前言 火焰原子吸收光谱法测定海水及其他天然水中的痕量锌,已有不少报导。一般都采用甲基异丁酮(MIBK)萃取吡咯烷二硫代氨基甲酸铵(APDC)、二乙基二硫代氨基甲酸钠(DDTC)、8-羟基喹啉、双硫腙等金属螯合物的方法。其中以APDC/MIBK萃取体系最佳,因其可以在较低的pH值条件下进行萃取,消除了氢氧化物共沉淀及氰离子等的隐蔽作 相似文献
5.
本文提出了在HCI-锑(Ⅲ)-钼酸铵和丙酮-丁酮体系中,用极谱法测定海水中活性磷的方法。其锋电位为-0.42V(对SCE),测定下限为6×10-8mol/l,机理研究表明,此波属于杂多酸吸附波。 相似文献
6.
海水中硫酸根的测定至今仍用费时的重量法。铅离子选择性电极虽能准确地测定SO_4~_,但样品中大量的Cl~-干扰SO_4~(2-)的测定。Mascin为使海水中的SO_4~(2-)与Cl~-分离,将海水样品通过Ag~ 型阳离子交换树脂分离海水中的Cl~-,接着又通过H~ 型阳离子树脂(树脂层均为15×0.5cm)分离Ag~ ,最后将流出液调到pH 5—6后,用铅离子选择性电极为指示电极进行电位滴定。该方法较烦,且树脂易被Ag~ 氧化而使交换容量变得很低。Scheide采用将样品稀释100倍,不经分离而直接在80％异丙醇溶液中进行Gran 相似文献
7.
本文报导了用气相色谱测定法,测定海水中苯酚及甲酚异构体的方法。水样进行溴化,溴代酚用石油醚萃取,然后用ECD检测器进行测定,这个方法在快速和准确测定海水中挥发酚方面优于4-AAP法。我们已将这个方法用于黄河口海域挥发酚的调查工作上。 相似文献
8.
中国系列标准海水是采用盐度为34.4左右的天然海水经低温浓缩和用去离子水稀释来制备的。本文描述了制备中国系列标准海水的工艺流程,制备方法及标准值的不确定度进行了探讨。 相似文献
9.
本文报导了用气相色谱测定法．测定海水中苯酚及甲酚异构体的方法。水样进行溴化。溴代酚用石油醚萃取．然后用ECD检测器进行测定。这个方法在快速和准确测定海水中挥发酚方面优于4-AAP法。我们已将这个方法用于黄河口海域挥发酚的调查工作上。 相似文献
10.
碲为毒性元素,有害人体健康,近年来微量碲的监测工作日益受到重视.文献报道用原子吸收光谱法测定了工业废水中ppb级的碲[1]及含量较高的人工水样[2].由于天然水中碲的含量极低,约为ppt数量级,目前尚无灵敏的方法可用于测定天然水中碲的本底值,而化学海洋学中也缺乏关于海水中碲含量的数据[3].本文目的在于研究超痕量碲测定的简便方案,即巯基棉浓缩-催化极谱法.首次测定了海水中碲的含量. 相似文献
11.
建立了测定天然海水中硝酸盐氮同位素组成的蒸馏法,该方法主要是在碱性条件下利用戴氏合金将海水中的硝酸盐还原为氨,后利用稀盐酸吸收生产的氨,将得到的氨吸收液浓缩后干燥结晶,利用同位素比值质谱仪测定所得晶体的氮同位素组成。研究中开展了戴氏合金添加量及氨吸收溶液在不同条件下干燥结晶对氮同位素测值的影响研究。结果表明,戴氏合金添加量为3.0 g及60 ℃下直接干燥结晶为最佳的实验条件。所建立的氨蒸馏法氮空白值仅为(0.90±0.19) μmol,低于此前文献报道的氮空白值;氮同位素组成(δ15N)空白值为(-14.7±4.1)×10-3。运用所建立的氨蒸馏法实测得到的硝酸盐δ15N值与氨扩散法、硝酸盐直接测定法得到的数值非常吻合,进一步证明所建立氨蒸馏法的可靠性。改进后的氨蒸馏法适用于硝酸盐浓度在2~50 μmol/dm3内的天然海水硝酸盐氮同位素组成的测定,方法的标准偏差为±0.3×10-3。 相似文献
12.
近年来,在一般分光光度法—比色法的基础上,发展起来了一个新方法,使得比色法似乎在返老还童,又可与原子吸收、放化分析、极谱法竞相争雄了。这个新方法就是离子交换剂直接比色法[1,2]这个方法的特点是(1)以半透明的离子交换剂为显色媒体直接进行光度测定;(2)离子交换剂能自稀溶液中富集待测成份,在一定条件下使待测成份在树脂上显色,之后不经过淋洗,即进行光度测定。这就把一般方法中“分离富集”和“光度测定”两步巧妙地合并成一步,结果使得本方法具有高灵敏度、简便快速等优点。但是,因为这一方法只是近年来才在文献上出现,所以在许多方面很不成熟,尚待不断改进和完善,特别是把此法应用到海水中微量元素的分析上,在文献上还未见有详细的和有效的研究结果报导。 相似文献
13.
东海外陆架及钓鱼岛以北海域鱼类、底栖生物的痕量金属测定 总被引：1，自引：0，他引：1
从海洋生物生态学本身的研究,生物体常量,微量元素的测定,前人已作了很多的工作。随着国防、工业及海上交通运输不断高速发展,各种工业废物大量抛入海洋,海洋污染日趋严重。为此,许多海洋学者又从海洋环境保护出发,对各个海域里的生物成分进行了监测,特别对生物体痕量金属的测定已作了大量工作[3-6]。测定的范围是广范的,从大洋到极地,从深海到岸边,而对受污染严重的港湾及河口的生物毒物研究得更多。 相似文献
14.
C.M.G Van Den Berg 《Marine Chemistry》1982,11(4):323-342
The MnO2 adsorption method combined with voltammetry is proposed for the direct determination of metal complexation in seawater of various salinities as a more satisfactory alternative to direct voltammetric measurements and bioassay methods. A small quantity of MnO2 is equilibrated with copper ions in filtered seawater. Natural organic ligands in the seawater compete for copper with the MnO2. Total dissolved copper is measured by differential pulse anodic stripping voltammetry after filtration and acidification of the sample. Preconcentration of natural water samples is unnecessary and measurement is performed at the natural equilibrium pH of the aerated sample. The analytical limit of detection of the method depends on contamination from the filtration step, and for copper complexation a ligand concentration of 5 × 10?8 M was obtained. The sensitivity can be increased by use of radioisotopes as tracers. The method is very versatile in that complexation of various metals may be determined by any analytical method that measures total dissolved metal concentrations. Neither organic ligands nor their complexes with copper adsorb on the MnO2 at pH8, but at pH 1.8 MnO2 is an efficient scavenger for electroactive organic material.Samples of surface water from the Irish Sea and the Atlantic Ocean were found to contain ligand concentrations of 1.7 × 10?7 and 1.1 × 10?7 M, with conditional stability constants (log values) of 9.84 ± 0.13 and 9.86 ± 0.23, respectively, at pH 8.0. 相似文献
15.
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. 相似文献
16.
《Marine Chemistry》2007,103(1-2):122-130
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. 相似文献
17.
A method for the determination of nanomolar concentrations of orthophosphate in oligotrophic seawater developed by Liang et al. (2007) has been modified to make it fully feasible for shipboard application and for faster sample throughput with minimized
sample volume. The technique is based on the flow injection method with solid phase extraction on a Sep-Pak C18 cartridge
and colorimetric detector. The Schlieren effect was minimized by rinsing the cartridge sequentially with 5 mL water and 2
mL 95% ethanol solution. With three micro pumps in parallel, savings of up to 80% in amount of reagents and 25% volume of
seawater samples could be achieved in comparison to the previous method. Variation of stopped flow time and sample loading
time gave 3 different standard curves, which corresponded to 3 linear ranges within 3.4 and 515 nM. The modified method permits
the analysis of samples over a wide range of concentrations, and has been successfully applied to shipboard determination
of trace orthophosphate in more than 200 seawater samples during a one-month cruise in the South China Sea. For seawater at
concentrations of 20.6, 82.5, 206.2 nM orthophosphate, the relative standard deviations (RSD) (n = 6), determined daily for 6 days on board ship were 4.45%, 4.73% and 6.75%, respectively. Five seawater samples collected
in the Station SEATS (South East Asia Time Series Station at 18°N, 116°E) were analyzed using the present method both on board
and in a land-based laboratory, as well as with the magnesium hydroxide-induced coprecipitation (MAGIC) method, and showed
no significant difference according to the statistical t-test. 相似文献
18.
A procedure is suggested for direct determination of Sr in seawater using diluted seawater sample and background emission correction by FES. The standard deviation for 8 ppm Sr is better then 2 %, and the recovery of the added Sr is 97-105 %. 相似文献
19.
针对透明度盘只能在白天开展海水透明度测量,易受自然环境和人为因素影响、客观定量性较差的不足,提出了基于海水固有光学性质的海水透明度计算方法。该方法仿真透明度盘测量海水透明度的基本原理,采用蒙特卡罗方法,利用海水固有光学性质,计算透明度盘所处位置海水上涌光相对量,结合对比度传输方程和人眼阈值,建立了基于海水固有光学性质的海水透明度计算模型。利用2006年1月至2月共37组海水透明度的观测数据与该模型数值实验结果比较表明,测量与计算值平均绝对误差为1.1 m。利用该方法可以客观、定量、准确地计算海水透明度,并且为夜间海水透明度要素计算增加了一种新途径。 相似文献