气相色谱-质谱法测定水产加工制品中酚类抗氧化剂残留

本文建立了一种固相萃取-气相色谱-质谱检测法,用于检测水产加工制品中5种酚类抗氧化剂残留。5种酚类抗氧化剂为二丁基羟基甲苯(BHT)、丁基羟基茴香醚(BHA)、特丁基对苯二酚(TBHQ)、4-己基间苯二酚(4-HR)和没食子酸丙酯(PG)。研究过程如下:用乙酸乙酯提取样品,硅胶柱净化,正己烷、乙酸乙酯洗脱,气相色谱-质谱测定,外标法定量。研究显示:在质量浓度为0.05~10μg/mL范围内,抗氧化剂的响应值与质量浓度的线性关系良好,相关系数为0.997 1~0.999 8。在0.05~1mg/kg添加浓度下,丁香鱼干、虾干和干贝加标样品的日内和日间平均回收率为70.6%~119%,相对标准偏差为1.09%~9.80%;BHT、BHA、TBHQ和4-HR的检出限为0.01mg/kg,最低定量限为0.05mg/kg;PG的检出限为0.05mg/kg,最低定量限为0.25mg/kg。研究结果表明,本文建立的固相萃取-气相色谱-质谱检测法可以有效的检测出水产加工制品中的5种酚类抗氧化剂残留。     

莱州湾海域水体中有机氯农药和多氯联苯的浓度水平和分布特征

以固相萃取/气相色谱法测定了莱州湾海域水体中22种有机氯农药和多氯联苯类化合物的浓度水平和分布特征。结果表明,莱州湾海域表层水体中有机氯农药浓度范围为N.D.~32.7ng/L,底层水中的浓度范围为N.D.~11.7ng/L。在该海域水体中共检出有机氯农药3种,β-666是水体中主要的有机氯农药污染物。多氯联苯类在底层水样中检出2种,总浓度范围在4.5~27.7ng/L之间。该海域有机氯农药和多氯联苯的分布特征是近岸高,离岸低,由近岸向湾外延伸方向依次递减。并对莱州湾表层水中总有机氯农药与海水盐度、氯度、溶解氧和pH间的关系作了初步探讨,得出总有机氯农药与盐度、氯度间有一定的相关关系,相关系数均为0.59。方法测定5种有机氯农药化合物的空白加标回收率为97.3%~126.0%,相对标准偏差为2.8%~8.6%;测定5种多氯联苯类化合物的空白加标回收率为88.6%~151.8%,相对标准偏差为6.7%~10.4%。     

高效液相色谱法测定食品中嘌呤含量

为测定食品中嘌呤含量,建立了食品中多组分嘌呤含量测定的反相离子对高效液相色谱(RP-IP-HPLC)分析方法,对几种主要食品中的腺嘌呤、鸟嘌呤、黄嘌呤、次黄嘌呤含量进行测定。结果表明,采用Agilent XDB-C18色谱柱,水-甲醇-冰乙酸-10%四丁基氢氧化铵(V/V/V/V,879/100/15/6)为流动相,检测波长为254nm,流速为1mL/min时4种嘌呤可完全分离。测得4种嘌呤物质的回收率在91.8%~108.7%之间,方法的相对标准偏差(RSD)为2.7%~6.5%。不同种类食品中嘌呤总含量由高到低依次为:动物肝脏、动物肌肉、果蔬、菌类和蛋类。     

过氧化氢-茜素红s体系催化动力学分光光度法测量痕量钴(Ⅱ)

本文利用催化动力学原理,建立了新的测定痕量钴(Ⅱ)的分析方法。研究体系为:钴(Ⅱ)-茜素红s-过氧化氢-碳酸钠。所得的最佳反应条件为:pH=11.00,反应时间t=7.50min,反应温度θ=35.0℃,ρ(C_(14)H_7O_7SNa·H_2O)=6.400×10~(-2) g·L~(-1),Φ(H_2O_2)=7.200×10-2%。在该反应条件下,此分析方法的相对标准偏差为1.85%~2.96%,检出限为4.21×10~(-2)ng/mL。在淡水体系中相对标准偏差在1.93%~2.79%之间,而加标回收率在98.7%~101.3%之间。相较于其他测量方法,本文所建立的分析方法具有操作简单,分析温度低,准确度高,检出限低,分析时间短等优点。     

高效液相色谱法测定海水中溶解态游离氨基酸

采用邻苯二甲醛柱前衍生-高效液相色谱-荧光检测器(OPA—HPLC-FLD)联用技术分离测定了海水中的14种主要溶解游离氨基酸(DFAA),通过邻苯二甲醛—3-巯基丙酸(OPA—3-MPA)柱前衍生后,在XDB-C18柱上分离。不同氨基酸测定的精密度(RSD)为1.62%~3.80%,检测限为11.4~69.7 ng.L-1,海水加标回收率在92%~110%之间。利用该方法测得青岛近海表层海水中氨基酸浓度为0.015~0.284μmolL-1。     

ICP-MS测定聚碳酸酯塑料中锑及其不确定度评定

采用微波消解-电感耦合等离子体质谱法(ICP-MS)测定聚碳酸酯塑料中锑含量。考察了消解介质、消解样品量的选择对消解结果的影响,优化选择了电感藕合等离子体-质谱法(ICP-MS)的测定参数。在选定的最佳消解和测定条件下,称取0.200 0g聚碳酸酯塑料样品于5mL HNO3试剂下消解,实验相对标准偏差RSD为3.68%,对实验样品添加5.00ng/mL标准进行加标回收实验,加标回收率在95.1%~110.9%之间,检出限为0.022ng/mL。该方法具有准确、简便、快速等优点,可以满足聚碳酸酯触塑料材料中锑的检测要求。通过建立不确定性评定数学模型,分析了影响不确定度的主要来源,对样品质量、体积定容、仪器测量重复性、标准储备液、曲线拟合等影响不确定度的分量进行分析,最后计算出合成标准不确定度和扩展不确定度。ICP-MS法测试塑料中锑含量可以表示为(0.568±0.057)mg/kg,可使实验结果更具客观性和准确性。     

ICP-AES测定海洋生物体中13种元素的微波消解条件优化

报道了微波密闭消解正交试验条件优化电感耦合等离子体发射光谱法(ICP-AES),同时测定8种海洋生物体中硒、铁、锰、锌、钙、镁、锶、砷、镉、铬、铜、铅和镍等13种元素含量的实验结果。优化后的样品消解条件为加入的HNO3V:H O2 2V=6.0 mL:1.0 mL,第二步程序升温温度为170℃,消解时间20 min;测定标准曲线相关系数大于0.999,相对标准偏差为0.30%~2.55%,加标回收率为92.0%~104.8%,方法检出限为0.0010~0.0468μg/g。结果表明,优化后方法测定操作简便、具有高的灵敏度、准确度和精密度,且能多元素同时测定,适合于海洋生物样品中这些元素含量的准确测定,并可为评估海产品食用安全提供科学依据。     

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。     

海水中硫丹及衍生物气相色谱快速测定及应用

通过固相微萃取(SPME)技术富集海水中6种硫丹及其衍生物,使用气相色谱-电子捕获检测器(GC-μECD)测定和外标法定量,建立海水中硫丹及其衍生物的快速测定方法。结果表明:硫丹及其衍生物的线性范围为2.5～100.0μg/L,相关系数为0.990～0.998,检出限为0.10～21.30 ng/L。在3个加标条件(5,10和25μg/L)下,人工海水硫丹的加标回收率为85.60%～119.50%,相对标准偏差(n=6)为1.3%～7.8%。实际海水硫丹的加标回收率为90.60%～120.70%,相对标准偏差为1.6%～7.9%。该方法应用于青岛近岸海域海水的测试,在青岛近岸水体中未检出α-硫丹和β-硫丹,检出硫丹衍生物:硫丹醚(N.D.～1.758μg/L),硫丹内酯(1.040～11.260μg/L)和硫丹硫酸酯(1.009～6.091μg/L)。实际应用表明该方法前处理简便易行、灵敏度高,并可满足海水中硫丹及其衍生物的快速检测分析。     

CPA矩阵—催化动力学光度法同时测定镍和铁混合双组分的分析方法研究

本文根据催化动力学原理和CPA矩阵法成功地建立1种新的能同时测定水体中痕量金属铁(Ⅲ)和镍(Ⅱ)混合双组分的分析方法,并将该方法应用于实际水体中铁(Ⅲ)和镍(Ⅱ)的测定。并确定了同时测定铁(Ⅲ)和镍(Ⅱ)的最佳分析条件是:pH=2.00,t=25.0℃,V(1,10-菲啰啉)=2.00 mL,c(KIO4)=1.2×10-4mol·L-1,c(RAWL)=5.00×10-5mol·L-1,反应时间t=10 min。在确定的最佳分析反应条件下,铁(Ⅲ)的线性范围为0~70.00 ng·mL-1,镍(Ⅱ)的线性范围为0~60.00 ng.mL-1,所建方法的相对标准偏差为0.61%~2.32%。对铁(Ⅲ)和镍(Ⅱ)质量浓度分别在5.00~60.00 ng·mL-1范围内的12组铁镍混合液进行测定,回收率在95.4%~104.4%。对自来水和黄河水水样的测定结果表明:铁(Ⅲ)和镍(Ⅱ)的回收率为95.5%~99.0%。     

Microbial Biomass and Organic Nutrients in the Deep-Sea Sediments of the Central Indian Ocean Basin

In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance.     

海上大直径钢管桩打桩过程中桩周土强度弱化研究

海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。     

Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification

An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm.     

Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans

A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and 13-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSwlO175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus ShewaneUa dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria （ 〉 99% ）, but also between polar marine bacteria and bacteria from other aquatic environments （ ≥ 98.8% ）, including temperate ocean, deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level.     

Deep-Sea Sediment Compression Curves: Some Controlling Factors, Spurious Overconsolidation, Predictions, and Geophysical Reproduction

Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations.     

INFORMATION FOR AUTHORS

<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology,     

Estimation of Sediment Properties during Benthic Impact Experiments

Sediment properties, such as water content and density, have been used to estimate the dry and wet weights, as well as the volume of sediment recovered and discharged, during benthic impact experiments conducted in the Pacific and Indian Oceans. The estimates show that the weights of dry (355-1332 t) and wet sediment (1651-4888 t) recovered during the experiments, are not only a function of the total duration and distance covered during the experiment, but also depend on water content and density of the sediment. Estimation of dry sediment and its volumetric ratio in the discharge, are key parameters for calculating the discharged volume. The estimated volume of wet sediment recovered (1427-4049 m 3 ) as well as discharged (2693-6951 m 3 ) during the experiments, provide important inputs to evaluate the sediment resettlement and migration. Using these estimates, the average depth of excavation on the seafloor, can also been calculated. However, the stages of sediment recovery and discharge are expressed differently in some of the experiments. In order to standardize these, different stages have been identified, and definitions of certain terms have been suggested, for use in the future. The methods of calculating different properties, as well as weight and volume of discharged sediment are described in the paper for use in other applications concerning deep-sea discharges.