Sokolowski Adam, Richard Pierre, Fichet Denis, Radenac Gilles, Guyot Thierry
Laboratory of Estuarine Ecology, Institute of Oceanography, University of Gdansk, Al. M.Pilsudskiego 46, 81-378 Gdynia, Poland.
Mar Pollut Bull. 2003 Oct;46(10):1326-33. doi: 10.1016/S0025-326X(03)00241-8.
The application of trichloroacetic acid (TCA) as a shell extractant for preparation of soft body parts with reference to tissue metal concentrations (Cd, Cu, Pb, Zn) in shellfish has been evaluated on the example of the mud snail Hydrobia ulvae, a small marine prosobranch densely present in rocky and soft-bottom habitats of the eastern Atlantic. A solution of 0.1 M TCA was tested on individuals treated according to two different protocols: (1) thawed after freezing ("non-dried") and (2) thawed and air-dried to a constant weight ("dried"). Two points were investigated in detail to improve the method: individual soft tissue dry weight and tissue metal concentration following a standard digestion method. In both instances, the results were compared with those from manually dissected snails. Conditions for total shell decalcification of 60 individuals (3-4 mm long) were 5.5 h in 20 ml of 0.1 M TCA.No differences in individual soft tissue weight were observed between the treatments, indicating good efficiency of the TCA extraction with respect to weight of soft body parts. In contrast, tissue metal concentrations varied among treatments. The TCA extraction of the dried animals had a good recovery for Cd, most likely due to the lower solubility of Cd vital cellular components (proteins and mineral concretions) from the dried tissue. Satisfactory recoveries of the tissue concentrations of Cu and Pb were obtained for the non-dried individuals. This might be related to the specific distribution of metals in the organism (namely in the digestive glands and gonads) and their different chemical reactivity with TCA after the tissue was dried. Limited susceptibility of Zn-bearing protein bindings to complexing with TCA also accounts for significantly lower concentrations of Zn in the mud snail's soft tissue that was extracted. The 0.1 M TCA solution is therefore recommended for extraction of the shells of Hydrobia ulvae for tissue determination of Cd, Cu and Pb; however the treatment protocol does affect metal recovery and thus a consistent procedure should be followed. The extracted metals from the soft tissues and shells of the mud snails (on the basis of both metal concentrations and contents) were ranked in order of increasing contribution of soft body parts to the total (shell+tissue): Pb<Cd<Zn<Cu.
以泥螺（Hydrobia ulvae）为例，评估了三氯乙酸（TCA）作为一种贝壳提取剂在制备软体部分时对贝类组织金属浓度（镉、铜、铅、锌）的应用。泥螺是一种小型海洋前鳃亚纲动物，密集分布于东大西洋的岩石和软底栖息地。对按照两种不同方案处理的个体测试了0.1M TCA溶液：（1）冷冻后解冻（“未干燥”）和（2）解冻并风干至恒重（“干燥”）。为改进该方法详细研究了两点：个体软组织干重和采用标准消化方法后的组织金属浓度。在这两种情况下，都将结果与手动解剖的蜗牛的结果进行了比较。60只个体（长3 - 4毫米）的贝壳完全脱钙的条件是在20毫升0.1M TCA中处理5.5小时。处理之间未观察到个体软组织重量的差异，表明TCA提取在软体部分重量方面效率良好。相比之下，组织金属浓度在处理之间有所不同。干燥动物的TCA提取对镉有良好的回收率，这很可能是由于干燥组织中镉与重要细胞成分（蛋白质和矿物质凝结物）的溶解度较低。未干燥个体的铜和铅组织浓度回收率令人满意。这可能与金属在生物体中的特定分布（即在消化腺和性腺中）以及组织干燥后它们与TCA的不同化学反应性有关。含锌蛋白质结合物与TCA络合的敏感性有限也导致泥螺软组织中锌的浓度显著降低。因此，建议使用0.1M TCA溶液提取泥螺的贝壳以测定镉、铜和铅的组织含量；然而处理方案确实会影响金属回收率，因此应遵循一致的程序。泥螺软组织和贝壳中提取的金属（基于金属浓度和含量）按软体部分对总量（贝壳 + 组织）贡献增加的顺序排列为：铅 < 镉 < 锌 < 铜。
