A Robust Method for the Determination of Cr(VI) and Cr(III) in Industrial Wastewaters by Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry Combined with a Chelating Pretreatment with 2,6-Pyridinedicarboxylic Acid.

We have developed a method for the determination of Cr(VI) and Cr(III) in industrial wastewater by liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS) combined with a chelating pretreatment with 2,6-pyridinedicarboxylic acid (PDCA). The PDCA unified the chemical forms of the Cr(III) species in water samples by the formation of a stable Cr(III)-PDCA complex, which was then separated by a LC column. The chromatographic mobile phase at neutral pH and the column of a mixed-bed of anion and cation exchangers successfully separated not only the chromium species without any redox conversion, but also chloride, which interfered with ICP-MS detection. The method detection limits measured at m/z 53 were 0.66 µg of Cr L-1 for Cr(III) and 0.74 µg L-1 for Cr(VI) with a sample injection volume of 20 µL under a no gas mode. The recoveries of spiked Cr(VI) at 50 and 500 g L-1 into the fifteen kinds of industrial wastewater samples were satisfactory (>90%). The proposed method for the determination of Cr(VI) was also validated by comparing with a colorimetric method using 1,5-diphenylcarbazide prescribed by the ISO 11083 and the JIS K0102.

A Simple and Robust Method for Determination of Alkylmercury in Seawater and Industrial Wastewater by Phenylation Pretreatment Combined with GC-MS.

For determination of methylmercury (MeHg) and ethylmercury (EtHg) in seawater and industrial wastewater, a simple and robust analytical method was developed based on phenylation and solvent extraction followed by GC-MS measurement. Alkylmercury compounds were directly phenylated with sodium tetraphenylborate in water and extracted into toluene. The method detection limits obtained for MeHg and EtHg in pure water were 53.3 and 33.5 ng Hg L-1, respectively, which are almost 10 times lower than the environmental quality standards for water pollution in Japan (EQSJ): 0.5 µg Hg L-1. The recoveries of alkylmercury compounds from seawater and four kinds of industrial wastewater except for EtHg from treated wastewater of an optic lens factory were satisfactory (>90%) at 1- or 4-fold concentrations of the EQSJ. Contrarily, the low recovery of EtHg from the treated wastewater (75.4 ± 4.7%) was found to be caused by the rapid decomposition of EtHg into inorganic mercury.

A new air-cooled argon/helium-compatible inductively coupled plasma torch.

A new inductively coupled plasma (ICP) torch with an air-cooling system has been designed and developed for both argon and helium plasma. The same torch and impedance-matching network could be used to generate stable Ar- and He-ICP. The torch consists of three concentric quartz tubes. The carrier gas, plasma gas, and cooling gas flow through the intervals between each tube. In an experiment, it was found that Ar-ICP could form a stable plasma under the following conditions: RF power of 1 kW, plasma gas flow rate of 11 L min(-1), and cooling gas flow rate of 20 L min(-1). For He-ICP, an input RF power of 2 kW, which is two-times higher than that of a conventional He-ICP, could be constantly applied to the plasma with plasma gas and cooling gas flow rates of 15 and 20 L min(-1), respectively. Using this torch, it is possible to realize lower plasma gas consumption for Ar- and He-ICP and a high-power drive for He-ICP. It has been found that the air-cooling gas stabilizes the shape of the plasma due to the pressure difference between the cooling gas and the plasma gas.

Distribution and dynamic pathway of selenium species in selenium-deficient mice injected with (82)Se-enriched selenite.

In order to elucidate Se metabolism in a living body, (82)Se-enriched selenite was injected intravenously into mice fed Se-adequate and -deficient diets. We studied the time-dependent changes in the distribution of the labeled Se in organs, red blood cells, and plasma. The total Se was determined by flow-injection ICPMS, and Se speciation analysis was conducted by micro-affinity chromatography coupled with low-flow ICPMS. Total Se in almost all organs, including liver, showed the maximum at 1 h after injection. From speciation analysis, exogenous (82)Se as Se-containing proteins other than selenoprotein P (Sel-P) (selenium containing albumin (SeAlb) and extra cellular glutathione peroxidase (eGPx)), peaked at 1 h and quickly decreased from 1 to 6 h after injection, whereas that as Sel-P, peaked at 6 h, and gradually decreased from 6 to 72 h after injection. We found that there were two pathways for the transfer of Se in mice; one was as SeAlb until 1 h after injection, and the other was as Sel-P from 6 to 72 h after injection.

A new and known cytotoxic aryltetralin-type lignans from stems of Bursera graveolens.

A new 4alpha-aryltetralin-type lignan called burseranin (1) and a known analogous lignan picropolygamain (2) were isolated along with known triterpenes, lupeol and epi-lupeol from the methanol extract of stems of Bursera graveolens, which showed a remarkable inhibitory activity against human HT1080 fibrosarcoma cells. The whole structure of 1 was established based on combined spectral studies and the absolute structure for 2 was first confirmed by CD spectral evidence. In addition, cytotoxic activities of the stem (methanol) extract and its components are evaluated in this paper.