Protein skimmers

Protein skimmers, or foam fractionators, may also be used for water treatment, especially when growing larvae/small aquatic organisms (Chen et al, 1993a, b). These are normally used in tandem with another particle filter such as a micro-sieve or a depth filter. The removal of small sized particles in foam fractionators is achieved by gas bubbles, usually of air, which are released at the bottom of a water column. When the bubbles rise to the surface of the water column, particles and some dissolved organic... 

To improve the efficiency of protein skimmers, ozone gas can be used instead of air for bubble creation (ozone splits the organic matter so that the amount of surface-active components increases). The amount of ozone supplied is lower than that required to achieve full disinfection. It is important to be aware that foam will not be created in all water qualities some pollution in the water is required. If no foam is created by using air, the use of ozone can improve the foam creation. 

Ozone can be used in combination with protein skimmers. Here, a small doze of ozone, instead of air, is added to the water in the skimmer, improving the skimming. However, this is not a full disinfection and less ozone is... 

Smith et al. [26-28] demonstrated that by a further increase of the nozzle-skimmer potential difference the internal energy of the ions can be increased and fragmentation of the multiple-charge protein ions can be induced as a result of colhsion-induced dissociation (CID). This is called in-source CID in this text. 

Studies on the analysis and characterization of proteins by ESI-MS generally involve the direct infusion of a protein solution. This enables the determination of the molecular weight of the proteim Initially, the influence of a variety of experimental parameters, e.g., solvent composition, temperature, and influence of nozzle-skimmer potential, was studied for model proteins [10-13]. Given the diverse nature and properties of proteins, general statements on optimum solvent conditions... 

H. Zhai, X. Han, K. Breuker, F.W. McLafferty, Consecutive ion activation for top down MS Improved protein sequencing by nozzle-skimmer dissociation. Anal. Chem., 77 (2005) 5777. 

The spectrum (Figure 1.16) was obtained at low nozzle (spray capillary) to skimmer potential, so that there was little collisional activation of the protein. At a high potential, multiple loss of HI was observed (see Figure 1.17). All the peaks that contained Na +1 pairs have disappeared and were replaced by peaks with unpaired Na adducts. 

There have been many publications on the subject of sample preparation of biological samples. It is necessary to dilute biological samples because the large amounts of proteins and salts can cause an irreversible reduction of the analyte signal intensity due to clogging of the nebuliser, torch, sample and skimmer orifices. Dilution reduces the matrix effects and improves the accuracy on the internal calibration. ... 

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