Determination Of Trace Phosphorus In Surface Water And Hydrocortisone In Injection By Sequential Injection Analysis With Chemiluminescence Detection

In this dissertation, the sequential injection method combined with chemiluminescence detection technique was proposed"and applied for the determination of phosphorus in surface water and hydrocortisone in injections and satisfactory results were obtained.The first section of the dissertation concerned the review on the progress of analytical methods for the determination of phosphorus in recent years. The methods including spectrophotometry, molecular luminescence, chromatography, electrochemistry, and the flow injection analysis were introduced and their analytical performance was evaluated briefly.The second section of the dissertation described sequential injection analysis combined with chemiluminescence to detect trace amounts of phosphorus in surface water samples. The molybdophisphoric heteropoly acid formed by phosphate and ammonium molybdate in acidic condition generated chemiluminescence emission via the oxidation of luminol. A univariate approach was adopted for the optimization of experimental parameters. The CL intensity is proportional to the concentration of phosphorus in the range 1.60×10-7～3.26×10-6 g/L and 6.52×10-6～6.52×10-5 g/L (P) respectively. The detection limit (3σ) is 9.00×10-8 g/L (P). The relative standard deviation for eleven repeated measurements at 3.26×10-5 g/L levels is 0.9%. The method was applied to the determination of phosphorus in freshwaters and the recoveries is over 90.1%～105.0%. The sampling frequency is 85 samples per hour.In the third section, a simple, fast sequential injection system with chemiluminescence detection for the determination of hydrocortisone in injections was presented, based on sodium sulfite oxidized by potassium permanganate in H2SO4 medium with hydrocortisone as an enhancer. The CL intensity is proportional to the concentration of hydrocortisone in the range from 1.0×10-9～1.0×10-6 g/mL. The detection limit (3σ) is 5.6×10-10 g/mL and the relative standard deviation for eleven repeated measurements for 5.0×10-8 g/mL hydrocortisone is 1.9%. The method was applied to the determination of hydrocortisone in injections and the recoveries were over 99.7%～107.2%with a sampling frequency of 85 samples per hour.In the last section, a summary for the characteristic of SI-CL system was described.