A spectrophotometric analysis device for continuous or on-line measurement of solution concentration

A newly designed variable optical path length (VOPL) spectrophotometric analysis device for measurement of solution concentration is presented. The VOPL device can eliminate the measurement errors caused by the instability of light source, sensors and detector circuit. Compared to traditional spectrophotometric methods, it can further eliminate the errors caused by the corrosion or bioadhesion on optical elements and so on. Experimental results show that the VOPL device can obtain an accurate and much more stable calibration curve of concentration vs. absorbance compared to usual methods.