Development of on-line NIR urine analyzing system based on AOTF

In this paper, some key techniques on development of on-line NIR urine analyzing system based on AOTF (Acousto-Optics Tunable Filter) are introduced. Problems about designing the optical system including collimation of incident light and working distance (the shortest distance for separating incident light and diffracted light) are analyzed and researched. DDS (Direct Digital Synthesizer) controlled by microprocessor is used to realize the wavelength scan. The experiment results show that this NIR urine analyzing system based on AOTF has 10000-4000cm(-1) wavelength range and 0.3 ms wavelength transfer rate. Compare with the conventional Fourier Transform NIR spectrophotometer for analyzing multi-components in urine, this system features low cost, small volume and on-line measurement function. Unscrambler software (multivariate statistical software by CAMO Inc. Norway) is selected as the software for processing the data. This system can realize on line quantitative analysis of protein, urea and creatinine in urine.