Preparation and application of a molecularly imprinted monolith for specific recognition of domoic acid.

In this work, a molecularly imprinted monolithic column was synthesized by a facile procedure and was applied for specific recognition of domoic acid, an amnesic shellfish poison. The poly(4-vinylpyridine-co-ethylene glycol dimethacrylate) molecularly imprinted monolith was synthesized in a stainless steel column by in situ polymerization. Pentane-1,3,5-tricarboxylic acid was used as a dummy imprinting template instead of the highly toxic and expensive target molecule. It is the first time that a molecularly imprinted monolith is introduced for separation and detection of domoic acid. After optimizing the preparation conditions, the prepared imprinted monolith was systematically characterized and exhibited excellent stability and permeability as a HPLC stationary phase. The results of chromatographic analysis demonstrated that the molecularly imprinted monolith exhibited specific retention and selective recognition toward domoic acid, with an imprinted factor up to 3.77. Furthermore, the molecularly imprinted monolith was successfully applied for selective enrichment of domoic acid from biological samples. Graphical abstract A molecularly imprinted monolith was prepared by using a dummy imprinted template and was successfully applied for specific recognition of domoic acid.

[Biotoxicity of zinc in the marine sediment to amphipod Grandidierella japonica].

The utility of simultaneously extracted metals/acid-volatile sulfide (SEM-AVS) differences was investigated to explain the biological toxicity of zinc in the sediments to benthic organisms exposed in the laboratory to sediments. Amphipod Grandidierella japonica was selected to 10-day acute toxicity test for this purpose. The investigation results showed that when the molar difference between SEMZn and AVS (i.e., SEMZn-AVS) was < 0 mumol/g, the concentration of zinc in the sediment interstitial water was low and few toxic effects were observed. Conversely, when SEMZn-AVS exceeded 0 mumol/g, a dose-dependent increase in the relative concentration of zinc in the pore water was detected and apparent organisms toxic effects were observed. Together, the chemical data from this study compare with observations made in short-term exposures and thus support the use of AVS as a normalization phase for predicting toxicity in metal-contaminated sediments.

Metal exposure and bioavailability to a marine deposit-feeding sipuncula, Sipunculus nudus.

Sediments often constitute the major repository of metals and may be a potential source for metal bioaccumulation by marine deposit- and suspension-feeding invertebrates. In this study, we compared the uptake of Cd, Cr, and Zn from solute and sedimentary sources by a deposit-feeding peanut worm, Sipuncula nudus. The uptake rate constants determined for the three metals were generally low and were 0.0016-0.0020 l g(-1) d(-1) for Cd, 0.0107-0.0269 l g(-1) d(-1) for Cr, and 0.0235-0.0463 l g(-1) d(-1) for Zn. The uptake rate of Zn increased at a disproportionately slower rate with increasing Zn concentrations in the ambient water, indicating that Zn may have been partially regulated at a high Zn concentration. The assimilation efficiency (AE) of the metals was determined using a pulse-chase radiotracer technique. The AEs were in the range of 6-30% for Cd, 0.5-8% for Cr, and 5-15% for Zn. The sediment grain size and radiolabeling duration (between 7 and 30 d) did not affect the metal AE. There was no major difference in the metal AE from natural sediment collected from a contaminated environment. The desorption of metals from the radiolabeled sediments was also concurrently measured using the gut juice extracted from the sipuncula. Up to 63% of Cd was extracted by the gut juice, whereas only <4% of Cr was extracted by the gut juice. There was a significant relationship between the metal AE and the metal extraction by gut juice for Cd, whereas no significant relationship was found for Cr and Zn. Thus, the bioavailability study using the gut juice extraction method may indicate Cd bioaccumulation in the sipuncula. With a simple kinetic model, we show that the bioaccumulation of Cd, Cr, and Zn in the worms is largely dominated by sediment ingestion due to the low uptake from the solute phase as well as the high metal concentrations in the sediment. Thus, sediment should be considered as a direct source for metal accumulation in sipuncula when setting the sediment quality criteria.