Inhibition sensitivity of in vitro firefly bioluminescence quantum yields to Zn and Cd concentrations in aqueous solutions.

To elucidate the inhibition effects of Zn and Cd on the luciferin-luciferase reaction, we performed quantitative measurements of quantum yields and spectral shapes for in vitro firefly bioluminescence in aqueous solutions containing ZnSO, ZnCl, CdSO, and CdCl at different concentrations. Particular care was taken toward the equilibrium between metal ions and enzyme proteins, anion difference, solubility, and uncertainty evaluation. The bioluminescence quantum yields decreased almost linearly to the concentration of Zn and Cd below 0.

Triethanolamine-based esterquat in sediments: New analytical method, environmental occurrence, and homologue composition.

The cationic surfactant triethanolamine-based esterquat (TEAQ) is a main ingredient in commercial fabric softeners and is produced and used in large quantities. However, little information is available for its occurrence in the environment, particularly in sediments. Here, we developed an analytical method for quantifying TEAQ in sediment and investigated TEAQ contamination in Japanese river and lake sediments.

Freely dissolved concentration profile and Hyalella azteca toxicity of cationic surfactant C-benzalkonium in spiked-sediment toxicity test.

The freely dissolved concentrations (C) have been considered a useful metric for exposure of aquatic organisms to organic contaminants. However, C for cationic surfactants has rarely been measured, and its use in sediment toxicity tests has not been evaluated. In this study, C of the cationic surfactant benzyldodecyldimethylammonium (C-benzalkonium; C-BAC) in water-only and spiked-sediment toxicity tests with the amphipod Hyalella azteca was analyzed using a passive sampling method.

Utilization of Anion-exchange Guard Column as an Ion Chromatographic Column of Anions Including Application to Simultaneous Separation of Anions and Cations.

This study demonstrated that a guard column containing anion-exchange resin has the potential for use as a separation column for acid eluent. Specifically, a 1-cm long anion-exchange guard column with a 4.6-mm internal diameter provided good separation of monovalent inorganic anions, by elution of 8 mM tartaric acid or 4 mM malic acid.