A simple laboratory procedure has been used to obtain volatilization rate data for compounds of environmental interest. The measured parameter is the ratio of the evaporation rate constant of the chemical to the oxygen reaeration rate constant, k,C/h,o, which has been shown to be constant for volatile substances over a wide range of conditions. If the oxygen reaeration rate constant, kVo, can be estimated or measured in a natural water body or in a wastewater treatment unit, then the volatilization rate constant of the chemical under those same conditions can be estimated by multiplying the value of the ratio by the environmental value of kv0. The results suggest that the major environmental fate of many low-molecular-weight, nonpolar compounds will be volatilization.
Many cellular functions are regulated through protein isoforms. Changes in the expression level or regulatory dysfunctions of isoforms often lead to developmental or pathological disorders. Isoforms are traditionally analyzed using techniques such as gel- or capillary-based isoelectric focusing. However, with proper electro-osmotic flow (EOF) control, isoforms with small pI differences can also be analyzed using capillary zone electrophoresis (CZE). Here we demonstrate the ability to quickly resolve isoforms of three model proteins (bovine serum albumin, transferrin, alpha1-antitrypsin) in capillaries coated with novel dynamic coatings. The coatings allow reproducible EOF modulation in the cathodal direction to a level of 10(-9) m2V(-1)s(-1). They also appear to inhibit protein adsorption to the capillary wall, making the isoform separations highly reproducible both in peak areas and apparent mobility. Isoforms of transferrin and alpha1-antitrypsin have been implicated in several human diseases. By coupling the CZE isoform separation with standard affinity capture assays, it may be possible to develop a cost-effective analytical platform for clinical diagnostics.
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