Portable SpectroChip-integrated micro-electromechanical systems spectrometer for rapid colorimetric determination of silica in ultrapure water

Recent advances in micro-electromechanical systems (MEMS) based spectroscopy have made it possible to develop compact, high-resolution devices for rapid monitoring of silica in ultrapure water (UPW). This is important in semiconductor manufacturing as trace contaminants can degrade device performance. In this study, a portable spectrometer system based on SpectroChip technology and 810 nm near infrared (NIR) LED combined with the molybdenum blue method was presented for rapid and sensitive silica detection. The system integrates a MEMS micrograting with a complementary metal-oxide-semiconductor (CMOS) image sensor to achieve stable spectral performance and miniaturisation. System stability was verified through repeated measurements, with relative standard deviation (RSD) values below 1% during stability evaluation. The optimised cuvette design and control of reaction chemistry gave an estimated method detection limit (MDL) of 0.776 parts-per-billion (ppb), a concentration resolution of 1 ppb and low measurement variability. The total time of measurement was 6.5 min. The spectral accuracy of the spectrometer was ± 0.5 nm in the range of wavelength 300–1100 nm. The compact design, low power consumption, and USB-powered interface make it well suited for portable and point-of-use monitoring. These characteristics support its potential application in UPW distribution systems, cleanroom facilities, and other industrial monitoring environments following further validation under representative operating conditions. The proposed portable spectrometer demonstrates promising analytical performance and has the potential to serve as a compact alternative for rapid silica monitoring in UPW applications.