Affinity chromatographic purification of bovine lung endothelin receptor using biotinylated endothelin and avidin-agarose.

Endothelin receptor was purified from bovine lung by affinity chromatography using biotinylated endothelin and avidin-agarose. Endothelin was biotinylated with sulphosuccinimidyl 2-(biotinamido)ethyl-1,3-dithiopropionate, a reactive form of biotin with a cleavable spacer arm containing a disulphide bond designed for a simple elution by thiols. Starting from 3.5 kg of bovine lung, about 200 micrograms of pure receptor were obtained.     

Determination of glutamate-pyruvate transaminase activity in blood serum with a pyruvate oxidase/poly(vinyl chloride) membrane sensor

Pyruvate oxidase (E.C. 1.2.3.3.) is immobilized by adsorption on a wet PVC membrane. Glutamate-pyruvate transaminase activity (5–1600 IU l^?1) in serum is determined by a pyruvate oxidase sensor consisting of the immobilized pyruvate oxidase coupled to a platinum electrode for measuring hydrogen peroxide, after an l-alanine—α-ketoglutarate reaction. The assay requires ?60 s, and has a precision of 2–3%. Endogenous pyruvate should not interfere if measurements are made > 30 s after starting the reaction.     

The crystal structure and absolute configuration of the antitumor platinum complex trans(OH)-Pt(OH)2(malonato)(1R,2R-cyclohexanediamine).

The absolute configuration of the anti-tumor complex trans(OH)-Pt(OH)2(malonato)(1R,2R-cyclohexanediamine) was determined by X-ray anomalous scattering technique. The final unit cell was monoclinic, space group P2(1) with a = 9.142 A, b = 7.788 A, c = 11.946 A, beta = 96.48 degrees, Z = 2. The crystal structure was determined by direct method and difference Fourier synthesis, and refined to R = 0.025 and Rw = 0.033 based on 2768 independent reflections. The platinum atom has roughly octahedral coordination. The cyclohexane ring has the expected chair configuration, with two amino groups in equatorial positions while the malonato ligand, in contrast, shows a boat conformation for six membered Pt O-C-C-C-O ring.     

A new method of plutonium speciation in sea water

A new method of plutonium speciation in large volume of sea water was developed by using adsorption of Pu(IV)-Xylenol Orange chelate and Pu-Arsenazo chelate on XAD-2 resin, respectively. The tetravalent plutonium ion reacts selectively with Xylenol Orange in acid solution and that adsorbed on XAD-2 resin. Total plutonium can be collected onto the resin in the form of its Arsenazo-III complex. The determination of plutonium then was carried out by alpha-ray spectrometric method after decomposition of organic complexes and ion exchange separation. The present method is confirmed for convenient and rapid preconcentration procedure for plutonium shipboard chemistry.     

Rapid oligosaccharide synthesis using a fluorous protective group

The Bfp-OH, a novel fluorous protecting reagent, was able to be easily prepared. The Bfp group was readily introduced to a carbohydrate, removed in high yield, and recyclable after cleavage. The use of the Bfp group made it possible to synthesize a pentasaccharide by minimal column chromatography purification. Each synthetic intermediate was able to be easily purified only by simple fluorous-organic solvent extraction and monitored by TLC, NMR, and MS.     

Determination of a strong organic ligand dissolved in seawater: Thorium-complexing capacity of oceanic dissolved organic matter

Studies have been made of loose water tritium (LWT) distribution and behavior in the soil samples taken from the region within a radius of 2 km to the HWRR stack of CIAE. The analytical results show that the LWT concentrations in most soil samples of the region are in the range from 24.8 Bq/l (3.6 Bq/kg) to 116 Bq/l (16.0 Bq/kg) with an average value of 58.1±24.8 Bq/l (10.3±4.5 Bq/kg). There are two areas with a higher LWT content; the first one (4.61 · 10⁴ m²) is located near HWRR with ahighest LWT concentration of 287 Bq/l (55.8 Bq/kg) and the second one (3.27 ·10⁵ m²) is located near Lab. A with a highest LWT concentration of 2.35 · 10⁴ Bq/l (2.56 · 10³ Bq/kg). It is estimated that the LWT inventories deposited in soil of the two areas are about 1.52 · 10⁹ Bq and 1.42 · 10¹⁰ Bq, respectively. The analytical results have been evaluated by comparing the possible tritium intake of the human body with the annual limit of intake recommended by ICRP, it can be concluded that the operations of all the nuclear facilities releasing tritium in CIAE are safe without causing any notable tritium contamination.     

Sample enrichment by using monolithic precolumns in microcolumn liquid chromatography

An on-line sample enrichment system was designed using monolithic precolumns in microcolumn LC. The monolithic ODS capillary columns were prepared via in situ sol-gel processes. The enrichment efficiency of the monolithic columns was tested by using phthalates as the analytes. The relative standard deviations (n = 6) for the retention time, peak area and peak height were between 0.4 and 1.2%, 0.9 and 5.5% and 0.4 and 3.9%, respectively. The system was linear (R2 > 0.99) within the working sample concentration and sample volume ranges. Comparing to 0.2 microl injection with a typical sample injector, the theoretical plate number of a same separation column was increased by 3-6-fold when the precolumn unit was used for sample injection. The recoveries of the analytes were between 88 and 120%, and the sample volume that could be injected into the system was increased up to 5000-fold. The limits of detection were improved by more than 2000-fold and were between 0.21 and 0.87 ng ml(-1) even with a UV absorbance detector. This system was applied to the determination of phthalates contained in laboratory distilled water and tap water samples.     

Cross-chiral examinations of molecular enantioselective recognition by fast atom bombardment mass spectrometry: Host–guest complexations between chiral crown ethers and chiral organic ammonium ions

Using fast atom bombardment (FAB) mass spectrometry (MS), cross-chiral relationships were confirmed for the first time for the diasteromeric host-guest complexations between the chiral crown ether host (1) and the chiral organic ammonium ion guest (2) on the basis of the relative peak intensities (RPI). Both host–guest combinations (R, R, R, R) – 1, (R) – 2 and (S, S, S, S) – 1, (S) – 2 obviously provided larger RPI values than the combination of both (R, R, R, R) – 1, (S) – 2 and (S, S, S, S) – 1, (R) – 2 by a factor of 1.6 as an averaged value: 1.87 (n = 4)/1.16 (n = 4) = 1.6. These results are consistent with the expected stabilities of the host-guest complexations by CPK model examinations. Successfully observed cross-chiral examinations strongly suggest a potentially useful FABMS/RPI methodology for rapidly searching newly designed and synthesized crown ether-like host compounds with a higher degree of enantioselectivity.     

Plutonium isotopes in the Sea of Japan

Plutonium isotopes in the Sea of Japan were determined to assess radioactive contamination. Concentrations of ^239,240Pu in surface water of the Sea of Japan were maintained at a constant level over the past two decades in contrast to ¹³⁷Cs. A median value of surface ^239,240Pu in the Sea of Japan in this period was 5.6 mBq/m³ with the range between 2.1 and 14.0 mBq/m³, which is slightly higher than that in the western North Pacific. The vertical distribution of ^239,240Pu showed a surface minimum, a subsurface maximum and gradual decrease with increasing depth. The ²⁴¹Pu/^239,240Pu activity ratios in water columns were almost constant except for surface water. In regard to ^239,240Pu in surface water of the Sea of Japan, these findings suggest that rapid recycling of deeper plutonium occurs in the Sea of Japan due to deep convection in winter and biogeochemical processes such as particle scavenging and remineralization.     

Plutonium in seawater of the Pacific Ocean

The present plutonium levels in the Pacific Ocean are summarized. The ^239,240Pu concentrations in surface seawaters in the early 2000s were in the range of 1.5 to 9.2 mBq·m⁻³ in the North Pacific and 0.8 to 4.1 mBq·m⁻³ in the South Pacific. There is no marked difference of surface ^239,240Pu distributions between the North and South Pacific subtropical gyres. The vertical profile of ^239,240Pu in the South Pacific was the similar pattern to that in the North Pacific, which is controlled by biogeochemical processes. The ^239,240Pu inventories (down to 2300 m) in the North Pacific are generally greater than that in the South Pacific, which reflects the geographical distribution of global fallout and effect of close-in fallout in the Marshall Islands.