Collection of trace heavy metals complexed with ammonium pyrrolidinedithiocarbamate on surfactant-coated alumina sorbents.

Surfactant aggregates were formed on alumina surfaces by mixing 100 mg of sodium dodecyl sulfate (SDS) and 1.5 g of gamma-alumina in 50 ml of water. The SDS-coated alumina incorporated water-insoluble metal-ammonium pyrrolidinedithiocarbamate complexes over the pH range 2-8 with a recovery of > 97%. The metals were quantitatively desorbed from the alumina with 4 mol 1(-1) nitric acid, leaving > 99% of SDS on the solid phase. They were determined by inductively coupled plasma mass spectrometry or graphite furnace atomic absorption spectrometry. The proposed method was successfully applied to the determination of traces of iron, cobalt, nickel, copper, cadmium and lead in high-purity alumina.

Purification and characterization of RNases from fission yeast under nitrogen-starvation.

Two RNases were purified from nitrogen-starved fission yeast cells in which cellular RNA was being degraded drastically. The two RNases showed similar properties. Their molecular weight in native form was about 170kDa. They were endoRNases which required divalent cations.