Studies On The Determination Of Proteins And Surfactants By Light Scattering Spectrometry

In this thesis, light scattering(LS), especially resonance light scattering(RLS),was reviewed and two simple, rapid and sensitive RLS methods were developed todetermine proteins and a sensitive and accurate LS method was built to detect CS.The possible mechanisms of the interaction between probes and target analytes havebeen disccussed and the applications of the methods were used to the sampleanalysis.Firstly, (NH4)2SO4 protein systems were investigated by RLS spectrometry.Protein solution has a colloidal propety and its molecular diameter is the same as thatof colloidal particles. When the concentration of a neutral salt[such as (NH4)2SO4] isin a definite range, the activity of aqueous molecules decreased greatly, which canresult in the precipitation of proteins. Ammonium sulphate, (NH4)2SO4, is one of themost important salts used for precipitation of proteins because of its high solubility,low density, good stabilization and low price. Based on the precipitation happenedbetween (NH4)2SO4 and proteins which can lead to the deposition and collection ofproteins and can induce the enhancement of RLS intensity, (NH4)2SO4 was used as anew RLS probe to determine bovine serum albumin(BSA), human serumalbumin(HSA) and ovum albumin(OVA). The effects of pH value, (NH4)2SO4saturation and coexistence substances were examined. Under the opitical conditions,the calibration curves were constructed, and the detection limits of BSA, HSA andOVA can all reach to the level of 10 9 mol/L. The synthetic and real samples were also analyzed by this assay and the results are in agree with the results obtained byCoomassie Brilliant Blue(CBB) method. It can be concluded that the proposedmethod is suitable for the determination of proteins.Secondly, the RLS spectra of proteins reduction agents anionic surfactantssystems were investigated. The reason for the use of anionic surfactant(AS) todetermine biomacromolecules by RLS is that when pH