Storage and processing of estuarine water samples for trace metal analysis by atomic absorption spectrometry

Saline water samples from the Delaware Bay estuary were sampled, processed, and stored in a variety of ways to allow different methods of maintaining their integrity to be compared. Samples were processed onboard ship, immediately after collection, by extraction with ammonium pyrollidinedithiocarbamate in methyl isobutyl ketone. Duplicate samples were processed onshore after a variety of storage procedures. All samples were analyzed for copper and iron by atomic absorption spectrometry. Only samples filtered (<1 μm), acidified, and stored frozen gave extractable copper and iron results comparable with those for samples extracted immediately after collection. Cold storage with sample acidification in polyethylene containers appeared less satisfactory. Organic extracts from samples processed onboard are best retained in all-Teflon containers pending complete digestion and analysis onshore. Unless clean (ultra-filtered air) conditions can be ensured onboard, the estuarine water samples are best returned in a filtered, acidified, and frozen condition for onshore processing.     

The Preparation of Substituted 1(2H)-Isoquinolinones from Dilithiated 2-Methyl-N-arylbenzamides, 2-Methyl-N-(arylmethyl)-benzamides,or 2-Methylbenzoic Acid, 2,2-Dimethylhydrazide

2-Methyl-N-arylbenzamides (N-aryl-ortho-toluamides), 2-methyl-N-(arylmethyl)-benzamides (substituted benzyl, N-benzyl-ortho-toluamides), or 2-methylbenzoic acid, 2,2-dimethylhydrazide (ortho-toluic acid, N,N-dimethylhydrazide), were dilithiated with excess lithium diisopropylamide, and the resulting polyanion-type intermediates were condensed with aromatic esters followed by acid cyclization to the 3-substituted-1(2H)-isoquinolinones (isocarbostyrils).     

Synthesis of alpha-amino acids by reaction of aziridine-2-carboxylic acids with carbon nucleophiles

A variety of homochiral alpha-amino acids have been prepared in good yield via regioselective reaction of higher order cuprates with (2S)-N-para-toluenesulfonylaziridine-2-carboxylic acid 4. The reaction was much less regioselective and low yielding when higher order cuprates were reacted with the more hindered aziridine carboxylic acid 30, the principal products being protected beta-amino acids. Reaction of lithium trimethylsilylacetylide with the aziridine acid 30, however, gave a protected alpha-amino acid which was converted to the protected isoleucine ester 37.     

The effects of stretching on wool fibres as monitored by FT-Raman spectroscopy

FT-Raman spectroscopy coupled with amide I band deconvolution was used to monitor the conformational changes of the peptide backbone of sulphite pre-treated wool fibres during stretching. The spectral changes observed are consistent with the transition of -helical to β-pleated sheet structure. These changes, which are most rapid during the early stages of stretching, can be related to protein secondary structure at both the crystalline and molecular levels. Analysis of the amide III region of the spectra reveals that a very small amount of additional disorder is imparted to the peptide backbone as a result of stretching. The consistency in the widths at half-height of the amide I band components implies that stretching does not significantly change the distribution of peptide chain conformations. From the Raman analysis of cells isolated from the stretched fibres, it is evident that conformational changes occur in both the cuticle and cortex. The most evident change, however, is in the cortical cells.