A label-free chemiluminescence (CL) immunoassay has been developed based on copper-enhanced gold nanoparticles for determination of human growth hormone (hGH). Au nanoparticles were immobilized on polystyrene well as nuclei for deposition of metallic copper and adsorption of antibodies. The immobilized human growth antibody was captured by human growth hormone. The copper enhancer solution was added to deposit copper on the gold nanoparticle as catalyst. After dissolved with HNO 3 , the released copper ions were quantified by CL. The designed sensor has more dynamic range than the other previously reported immunosensors for determination of hGH. In the next work, a new sensitive method was introduced for analysis of glutathione (GSH) at trace levels in blood samples. The method was based on the effect of glutathione on the chemiluminescence signal of the oxidation of luminol by sodium periodate in basic solution. Common amino acids did not have any significant interference on the determination of GSH, therefore this method is suitable for measuring glutathione in blood samples. In the next work,batch chemiluminescence (CL) method couped by least-squares support vector regression (LS-SVR) as a multivariate calibration method was used to simultaneous determination two structurally similar alkaloids (noscapine and thebaine) and phenothiazines (fluphenazine and promazine). The method is based on the kinetic distinction of the CL reactions of these drugs with Ru(II) and Ce(IV) system in a sulfuric acid medium. The parameters of the model, consisting of ? 2 and ?, were optimized by constructing LS-SVM models with the possible combinations of these two parameters and the model with the minimum root mean squared error of cross validation (RMSECV) was selected as the best and the parameters of this model were chosen as the optimized values. In the next work, batch and flow injection chemiluminescence (CL) methods have been developed for the simultaneous determination of two structurally similar ?-lactams including amoxicillin and clavulanic acid (CLAV). LS-SVR was applied to relate concentration of both compounds to their CL profiles. The performance of LS-SVR model was compared with Partial Least Squares (PLS) and the results revealed the superiority of the LS-SVR over PLS model.