Optofluidic Platform for Rapid On-Chip Analysis of Total Phosphorus in Surface Water Using Absorption Spectrometry

Abstract

Optofluidic devices are of high interest for online monitoring and analyzing biochemical targets in water by integrating the complex on-chip pretreatment of target analytes and spectral analysis. Compared with the traditional bulk equipment, versatile optical detection and biochemical analysis are more easily integrated on an optofluidic chip, which promotes the development of on-chip real-time rapid detection and monitoring. Here, we report an optofluidic platform for online monitoring total phosphorous in water by absorption spectrometry, which naturally combines the merits of both the photo-Fenton effect and microfluidics to realize the rapid on-chip digestion of phosphate at room temperature and normal pressure. The functional cells for chromogenic reaction and optical absorption detection are respectively fabricated on the platform to analyze the content of total phosphorus in surface water. In the experiment, the on-chip digestion time of phosphate is dramatically declined to 8.6 seconds and thus the detection time is greatly shortened to a few minutes. The detection range of total phosphorus is demonstrated as 0.005–1.00 mg/L, which satisfies the detection requirements of most environmental water samples. Its availability for measuring the total phosphorous in real water samples is also verified. Predictably, this platform is adapted to on-chip analyze many other biochemical targets in water.

Toward point‐of‐care diagnostics: Running enzymatic assays on a photonic waveguide‐based sensor chip with a portable, benchtop measurement system

“…Smartphone modules for sensing, microscopy, and spectroscopy have been developed, using either the onboard LED and camera or external light sources and sensors [7]. Proposed handheld absorption sensors in literature mostly rely on free space absorption in a cuvette or fluidic detection volume [3,[7][8][9]. However, for enzymatic assays, the smartphone-based modules based on free space propagation through the sample are limited in use due to the limited interaction length of the light with the sample.…”

Photothermal Localization in an Optofluidic Microreactor for Rapid Pretreatment toward Online Pollutant Analysis

“…But some nutrients in surface water need to be pretreated, such as digestion, before they can be detected. Therefore, in our previous work, the microfluidic devices based on thermal digestion and Fenton catalysis were developed to on-chip digesting the total phosphorus water samples toward its online detection, which integrated with the pretreatment digestion unit for water samples, the chromogenic unit, and the optical detection unit. , However, although many pretreatment methods, such as photocatalysis, − microwave catalysis, and advanced oxidation, have been utilized to digest nutrient samples due to their merits of nontoxic, clean, and no secondary treatment, their applications are limited by the inefficient on-chip digestion, which caused the large online measurement errors. − …”