Analytical Laboratory 

Abstract: The amounts of nitrogen and organic substances in soils were determined by near infrared diffusion reflectance spectroscopy. A matheatical model was developed by partial least square method. Cross validation was used to determine the optimal rank of calibration set. The satisfactory results showed that the method was feasible to predict the amount of nitrogen and erganic substances in different kinds of soil samples.

Abstract: A novel tramadol hydrochloride ion membrane electrode is prepared, characterized and used in pharmaceutical analysis. Based on the influences of concentration of activator in membrane phase and plasticizer, an electrode system with tramadol-tetraphenylboron is seclected as the electroactive material, DOP as the plasticizer. The electrode exhibits a fast near-Nernstian response for 5×10~(-5)～1×10~(-2) mol/L tramadol with the slope of 57.1 mV/decade. The minimal detection limit is 1×10~(-5) mol/L . The electrode displays a good selectivity for tramadol in the presence of a number of foreign ions. Tramadol in the medicine has been determined by potentiometry with satisfactory result. The recovery is 94.9%～106.0%.

Abstract: A HPLC method was developed for determination of gibberellin(GA 3) and 3 indole acetic acid(IAA) in earthworm casts. The pre separation and purification procedures for hte samples were simplified. The linear ranges for determination of GA 3 and IAA were from 0.03 to 19.3 μg and 0.01 to 6.4 μg, respectively, with correlation coefficient of 0.99999. The detection limits of GA 3 and IAA were 0.02 μg and 0 004μg, respectively.

Abstract: A method for the determination of pyruvate was studied by ultraviolet spectrophotometry in this paper. At pH 11.0 and 320 nm, pyruvate achieved higher absorptivity than other organic acids and coexistent components. Beer′s law was obeyed for pyruvate in the concentration range from 0.2 to 2.8 g/L. This method is simple and has high selectivity for the determination of pyruvate in the fermentation broth and its product.