Selective detection of carboxylic acids, ureas and phenols and semiquantitative determination of citric acid by capillary solid-state spot-tests

Solid-state spot-tests for the selective detection of carboxylic acids, ureas and phenols have been developed. Mixtures of p-dimethylaminobenzaldehyde with N-methylurea and of p-dimethylaminobenzaldehyde with phthalic acid are used as reagents. Based on these tests a semiquantitative determination of citric acid is also developed. These tests utilize three properties of the coloured boundary: colour, length and direction of movement. Our work on capillary solid-state spot-tests,(1) has now been extended to some further organic compounds.     

Butanol fermentation research: upstream and downstream manipulations

An overview of advances in acetone-butanol fermentation research is presented with specific reference to the history of acetone-butanol fermentation, genetic manipulation of the butanol-producing Clostridium beijerinckii NCIMB 8052, as well as upstream and downstream processing. Specific reference is made to the development of the hyperamylolytic, hyper-"butanolagenic" C. beijerinckii BA101 strain. Amylolytic enzyme production by C. beijerinckii BA101 was 1.8- and 2.5-fold greater than that of the C. beijerinckii NCIMB 8052 strain grown in starch and glucose, respectively. We confirmed the presence of a phosphoenolpyruvate (PEP)-dependent phosphotransferase system (PTS) associated with cell extracts of C. beijerinckii BA101 by glucose phosphorylation by PEP and ATP-dependent glucose phosphorylation. It was found that C. beijerinckii BA101 was defective in PTS activity and that it compensates for this defect with enhanced glucokinase activity, resulting in an ability to transport and utilize glucose during the solventogenic stage. The principal problem associated with acetone-butanol fermentation by C. beijerinckii or C. acetobutylicum is butanol toxicity/inhibition to the culture. To solve this problem, we have attempted various alternative in situ/online techniques of butanol removal including membrane-based systems such as pervaporation, liquid-liquid extraction, and gas stripping. We found that gas stripping and pervaporation appear to be the most promising of the in situ acetone-butanol fermentation and recovery techniques but, in terms of cost-effective industrial applications, gas stripping appears to be the most promising.     

Use of high performance liquid chromatography in defining the abnormalities in the free amino acid patterns in the cerebrospinal fluid of patients with aseptic meningitis.

Free amino acids were quantitatively determined in cerebrospinal fluid (CSF) and plasma samples from patients with aseptic meningitis by a newly developed high performance liquid chromatographic (HPLC) method. The method of analysis was based on precolumn derivatization of orthophthaladehyde in the presence of 2-mercaptoethanol and detection was made at Eex = 340 nm and Eem = 450 nm. The method was sensitive and the limit for detection was less than 1 pmol for most of the amino acids. It took 45 min to separate 26 amino acids with highly reproducible results, giving a coefficient of variance for retention times and integrated areas less than 0.4% and 2%, respectively, after five replicate runs. The results accumulated in 10 patients were compared statistically with 11 age-matched healthy controls. Among the amino acids almost all the neurotransmitter candidates, such as aspartic acid, glutamic acid, glutamine, glycine, tyrosine, phenylalanine and gamma-aminobutyric acid (GABA), were significantly increased in the patients' CSF, whereas arginine and threonine were low. No change was observed in plasma amino acids in patients as compared to healthy controls. The higher levels of most of the neurotransmitters, especially GABA, aspartic acid and glutamic acid, could be used diagnostically in assessing the progression and remission in aseptic meningitis.     

Comprehensive analysis of binary events in heavy ion reactions observed with dielectric track detectors

The dielectric track detectors are very efficient in registering the main fragments of a heavy ion reaction in the presence of lightly ionizing products and γ-radiations because of their threshold nature of registration and wide-angle acceptance. The binary events, revealed after chemical etching of these detectors, appear as the events having two correlated prongs in the body of the detector. The measurements of the geometrical parameters of these prongs provide the necessary data for subsequent kinematical analysis. We have made a thorough analysis of the two-pronged events in order to understand the physical mechanism of their production, using the track data from the reactions,     

A Novel and sensitive spot-test for m-dinitroaromatics and their derivatives with sodium sulphite and dimethylsulphoxide

Sodium sulphite has been used for a very sensitive characterization of m-dinitroaromatics and their derivatives, with dimethylsulphoxide as solvent.     

Fast mecury removal from industrial effluent

The use of a naturally available Lateritic Soil (LS) for the removal of mercury from industrial effluents has been investigated. Adsorption of Hg on LS from aqueous solution is reported, describing the effect of equilibration time, hydrogen ions, adsorbent and adsorbate concentration. The contact time required is less than two minutes and adsorption capacity is 15 g/kg.