Volatile halocarbons released from Arctic macroalgae     

Frank Laturnus 《Marine Chemistry》1996,55(3-4)

Twenty-two different species of Arctic brown, red and green macroalgae, collected in the Kongsfjord at Ny-Ålesund (Spitsbergen), were incubated under polar conditions and investigated for their release of volatile halogenated organic compounds (VHOC). Bromoform, dibromomethane, dibromochloromethane, bromodichloromethane, 1,2-dibromoethane, diiodomethane and chloroiodomethane have been identified and their net releases during incubations were determined. Generally, brown and green macroalgae showed higher VHOC release, while red macroalage had only low release. Bromoform was released in relatively large quantities from all species studied, with the highest release observed from the brown algae Dictyosyphon foeniculaceus (0.3 μg g⁻¹ wet algal weight day⁻¹) and Laminaria saccharina (0.15 μg g⁻¹ wet algal weight day⁻¹), and from the green algae Monostroma arcticum (0.3 μg g⁻¹ wet algal weight day⁻¹) and Blidingia minima (0.27 μg g⁻¹ wet algal weight day⁻¹). Dibromomethane, diiodomethane, dibromochloromethane and 1,2-dibromoethane showed lower net release during the incubations. The net release of chloroiodomethane and bromodichloromethane was very low for the most algae species investigated. Based on the distribution of these algae in the Arctic environment, Dictyosiphon foeniculaceus and Laminaria saccharina may be important sources for VHOC because of high release and high biomass. Release of VHOC could be detected from all parts of the thallus of the macroalga. This may provide some evidence for a possible role of VHOC production as a chemical protection mechanism in algae.  相似文献   

六溴苯的合成研究     

钱佐国  孙明昆  苗世昌  刘新河  周曾昊 《中国海洋大学学报(自然科学版)》1991,(2)

对直接溴化法合成六溴苯作了系统的研究,并对文献方法进行了一系列的改进。包括选择适当的摧化剂及其用量,使反应基本上在室温下进行;利用水汽蒸馏法驱除残余溴,可直接得到无色或近乎无色的纯净产物,而勿需进行还原脱溴,且得率较高。提出一种以溴化物形式回收副产物的方法。  相似文献   

微波消解-火焰原子吸收光谱法测定石英砂中的氧化钙和氧化镁     

鲁青庆 《岩矿测试》2005,24(4):314-316

采用微波消解-硼酸络合-火焰原子吸收光谱法测定石英砂中的氧化钙和氧化镁。样品在MK-Ⅲ型实验室微波炉上消解,消解压力为2.0 MPa、消解时间为5 m in,以硼酸络合消除氢氟酸的影响。方法已用于实际样品的测定,7次测定的相对标准偏差(RSD)小于5%,加标回收率为95.0%~104.2%。  相似文献   

醋酸丁酯萃取-无火焰原子吸收法测定化探样品中痕量金   总被引：3，自引：0，他引：3  

刘菊琴  杨永理  韦山桃 《矿产与地质》2003,17(3):261-262,F003

在KBr存在下,用小体积醋酸丁酯萃取金后,用无火焰原子吸收法测定化探样品中痕量金的分析方法较化学富集光谱法具灵敏度高(检出下限可达0.05×10-9)、精度好、简便快速、成本低等优点.通过批量化探样的检验,证明该方法足已满足化探样品对金的测定要求.  相似文献   

火焰原子吸收法间接测定磷矿中氯   总被引：2，自引：0，他引：2  

达刘生 《岩矿测试》1997,16(1):80-81

火焰原子吸收法间接测定磷矿中氯达刘生１云南个旧市化肥厂中心化验室个旧６６１４１１目前磷矿中Ｃｌ－含量的测定多采用浊度法、氯离子选择电极法及离子色谱法。本文采用火焰原子吸收法来间接测定磷矿中Ｃｌ－，即在试样溶液中加入定量的Ａｇ＋，试样中Ｃｌ－与Ａｇ＋生...  相似文献   

复杂矿石中滑石的测定   总被引：1，自引：1，他引：1  

郑大中 《岩矿测试》1991,10(3):193-196

含滑石复杂矿石试样经650℃焙烧,使其中绿泥石、菱镁矿等变得能迅速溶于1+1 HCl中,而滑石溶解率很低。残渣用HF-HClO_4或KOH处理,用火焰原子吸收法或滴定法测定MgO,计算滑石量。10余种共存矿物在一定范围内不干扰测定。  相似文献   

萃取富集-火焰原子吸收法测定碳酸钙中铅和镉     

黄俭惠  邱丽 《矿产与地质》2007,21(4):479-481

将碳酸钙试样用盐酸溶解后,在0.6mol/L的盐酸介质中,用KI-MIBK萃取试样中微量的铅和镉,有机相用原子吸收分光光度法测定。该方法测定铅的相对标准偏差为2.38%-6.31%,回收率为96.5%-97.0%;测定镉的相对标准偏差为4.50%-5.52%,回收率为96%-102.8%。结果可靠,具有灵敏、准确、快速、选择性好等优点。适用于碳酸钙中铅、镉的测定。  相似文献   

火焰原子吸收光谱法测定铜精矿中银含量的测量不确定度评定   总被引：2，自引：0，他引：2  

王巧玲 于明朱明达  耿刚强宁国东 《岩矿测试》2007,26(6):477-480

采用《测量不确定度评定与表示指南》，以火焰原子吸收光谱法测定铜精矿中的银含量为例，对测量结果进行不确定度评定。分析了不确定度的重要来源，包括称样质量、标准工作溶液、工作曲线拟合、试液定容体积及测量重复性等引入的不确定度分量组成。对各不确定度分量进行分析计算，求得标准不确定度为1．56，扩展不确定度为3．12。  相似文献   

国内氢氧化镁阻燃剂的研究现状   总被引：6，自引：0，他引：6       下载免费PDF全文

姬连敏  李丽娟  聂锋  曾忠民 《盐湖研究》2007,15(2):62-72

综述了国内氢氧化镁阻燃剂的合成、表面改性及其应用,主要论述了近20年来国内在氢氧化镁阻燃剂研发方面取得的成果及发展方向,简单概述氢氧化镁阻燃剂的发展前景。  相似文献   

Persistent organic pollutants and stable isotopes in biopsy samples (2004/2006) from Southern Resident killer whales     

Krahn MM  Hanson MB  Baird RW  Boyer RH  Burrows DG  Emmons CK  Ford JK  Jones LL  Noren DP  Ross PS  Schorr GS  Collier TK 《Marine pollution bulletin》2007,54(12):1903-1911

“Southern Resident” killer whales include three “pods” (J, K and L) that reside primarily in Puget Sound/Georgia Basin during the spring, summer and fall. This population was listed as “endangered” in the US and Canada following a 20% decline between 1996 and 2001. The current study, using blubber/epidermis biopsy samples, contributes contemporary information about potential factors (i.e., levels of pollutants or changes in diet) that could adversely affect Southern Residents. Carbon and nitrogen stable isotopes indicated J- and L-pod consumed prey from similar trophic levels in 2004/2006 and also showed no evidence for a large shift in the trophic level of prey consumed by L-pod between 1996 and 2004/2006. ∑PCBs decreased for Southern Residents biopsied in 2004/2006 compared to 1993–1995. Surprisingly, however, a three-year-old male whale (J39) had the highest concentrations of ∑PBDEs, ∑HCHs and HCB. POP ratio differences between J- and L-pod suggested that they occupy different ranges in winter.  相似文献