Humus removal efficiency from river water by a variety of methods and phycical-chemical properties of isolated humus

The efficiency of hwnic substances isolation, from river water was assessed utilizing a variety of techniques. Selected physical and chemical characteristics of isolates were analysed, in order to compare properties of the isolated material. It was found that the recovery of dissolved hwnus depends on a method employed for isolation. Thus it was equal to 70 % (extraction), 87 % (reverse osmosis), 33 % ( coprccipitation), 76 % (anion exchange), and ranged from 40 % to 87 % for a variety of solid sorbents. The efficiency of sorption/desertion on solid sorbents, measured as recovery of coloured substances (%), was equal to: activated carbon (100/40), weak anion exchanger DEAE (Cr) (95/95), styrene-divinylbenzene Amberlite XAD-2 (96/87), poliacrylamideAmberlite XAD-8 (98/87)

Comparison of analytical methods for Humic Like Substances (HULIS) measurements in atmospheric particles

Humic-Like Substances (HULIS) are a major contributor to the organic carbon in atmospheric aerosol. It would be necessary to standardize an analytical method that could be easily and routinely used for HULIS measurements. We present one of the first comparisons of two of the main methods in use to extract HULIS, using I) a weak anion exchanger (DEAE) and II) the combination of two separation steps, one according to polarity (on C18) and the second according to acidity (with a strong anion exchanger SAX). The quantification is performed with a TOC analyzer, complemented by an investigation of the chemical structure of the extracted fractions by UV-Visible spectroscopy. The analytical performances of each method are determined and compared for humic substances standards. These methods are further applied to determine the water extractable HULIS (HULISWS) and the 0.1 M NaOH alkaline extractable HULIS (HULIS T) in atmospheric aerosol collected in an Alpine Valley during winter time. This comparison, although on a limited batch of samples shows that the simpler DEAE isolation procedure leads to higher recoveries and better reproducibility than the C18-SAX procedure, and might therefore be preferable.

Comparison of analytical methods for HULIS measurements in atmospheric particles

Humic-Like Substances (HULIS) are a major contributor to the organic carbon in atmospheric aerosol. It would be necessary to standardise an analytical method that could be easily and routinely used for HULIS measurements. We present one of the first comparisons of two of the main methods in use to extract HULIS, using i) a weak anion exchanger (DEAE) and ii) the combination of two separation steps, one according to polarity (on C18) and the second according to acidity (with a strong anion exchanger SAX). The quantification is performed with a DOC analyzer, complemented by an investigation of the chemical structure of the extracted fractions by UV-Visible spectroscopy. The analytical performances of each method are determined and compared for humic substances standards. These methods are further applied to determine the water extractable HULIS (HULISWS) and the 0.1M NaOH alkaline extractable HULIS (HULIST) in atmospheric aerosol collected in an Alpine Valley during winter time. This comparison shows that the simpler DEAE isolation procedure leads to higher recoveries and better reproducibility and should therefore be recommended.

Liquid-chromatographic measurement of purine nucleotides in blood cells.

In this anion-exchange "high-performance" liquid-chromatographic method of analysis for purine nucleotides, the nucleotides are separated with high efficiency and selectivity on a weak anion exchanger (Hypersil APS 2, 3-micron particle size) by elution with a gradient of eluent pH and concentration. Applying this method to analysis for these compounds in human blood cells, we determined them in a patient with adenosine deaminase deficiency who was treated with a bone-marrow transplantation, finding that the transplantation did not entirely correct the patient's abnormalities of purine metabolism.