Ultrasensitive detection of glyphosate through effective photoelectron transfer between CdTe and chitosan derived carbon dot

The rapid on-filed detection of organophosphorus herbicide residue is a challenge for environmental protection as well as food safety. In this connection we have developed a CdTe-CQD integrated probe for the detection of herbicide glyphosate in aqueous medium. The photoluminescence (PL) spectrum of CdTe-CQD pair shows diminished fluorescence at 619 nm due to efficient photoelectron transfer from CdTe to CQD. When glyphosate is added into CdTe-CQD at pH 8, the disintegration of pair takes place hence which inhibits the PET process and regains the emission intensity of the probe at 619 nm. This sensing protocol works well in real samples. The fluorescence assay for glyphosate (F/F-0) covers a linear concentration range from 0 to 1000 nM and the detection limit is found to be 2 pM. Compared to previously reported quantum dot and metal nanoparticle based sensing methods our sensor is simple and works for a broad linear range with high sensitivity. The specific and selective recognition of our probe towards glyphosate even in presence of other organophosphorus pesticides makes it suitable for practical applications.