Sensitive measurement of silver ions in environmental water samples integrating magnetic ion-imprinted solid phase extraction and carbon dot fluorescent sensor

Abstract

Increasing use of silver in various fields has caused Ag+ pollution in water environment, taking great threats to people's health. As a consequence, establishing rapid and reliable methods for sensitive determination of Ag+ is of great significance. Fluorescent (FL) sensors based on carbon dots (CDs), an excellent carbonaceous nanomaterial with strong and stable fluorescence, have absorbed extensive attentions in analysis of pollutants due to its advantages of carbon sources being readily available, low cost, easy operation and fast response. Moreover, ion-imprinting is a better way to increase the selectivity of the proposed method. Present work described an effective method for the sensitive measurement of silver ion in water samples in combination with magnetic ion-imprinted solid phase extraction and CDs based fluorescent sensor, which took full advantages of easy separation and high enrichment of magnetic solid phase extraction, high selectivity of ion-imprinting technology, and sensitivity and rapid response of fluorescent sensor from CDs. Sulfur-doped CDs derived from dithizone and magnetic ion-imprinted nanomaterial were prepared, and characterized with Fourier transform infrared spectroscopy and transmission electron microscope, etc. Magnetic Ag+ imprinted nanomaterial based solid phase extraction was employed for separating and enriching Ag+ from water samples. The significant parameters were optimized in detail. Under the optimal conditions, the proposed method provided good linearity in the range of 0.01–0.4 µmol/L and low detection limit of 3 nmol/L. The reliability of the proposed method was validated with real water samples, and the results demonstrated that the proposed method was simple, robust, selective and sensitive detection tool for Ag+ in real water samples.