Surfactant stabilized AgNPs as a colorimetric probe for simple and selective detection of hypochlorite anion (ClO−) in aqueous solution: Environmental sample analysis

• Simple colorimetric probe for the detection of ClO− in aqueous media.
• Quenching in the absorbance of CPB-AgNPs with ClO− due to the inducing aggregation, resulting in the color change from yellowish brown to colorless.
• Straightforward method with LOD (0.4538 μg mL−1).
• The probe successfully applied to determine ClO− from environmental water samples.

Herein, the development of a colorimetric probe for selective detection of hypochlorite ion (ClO−) using cetylpyridinium bromide (CPB) capped silver nanoparticles (CPB-AgNPs) in aqueous solution is reported. The absorbance of the CPB-AgNPs was significantly decreased in presence of ClO− resulting in the color change from yellowish brown to colorless due to inducing aggregation of CPB-AgNPs with ClO−. The interaction between ClO− and CPB-AgNPs is studied by some analytical techniques such as UV–vis absorption spectroscopy, Transmission Electron Microscopy (TEM), Dynamic Light Scattering (DLS) and zeta potential measurements. Under the optimum condition, the calibration plot of (A0–A) against concentration of ClO− was linear in the range of 0.5–4.5 μg mL−1 with a correlation coefficient of 0.9927. The concentration of ClO− is quantitatively determined from an UV–vis spectrophotometer with a Limit of Detection (LOD) is 0.45 μg mL−1. This method shows excellent selectivity towards ClO− checked over other interfering anions. The accuracy and reliability of the methods were further ascertained for the detection of ClO− from environmental samples via standard-addition method, with percentage recoveries in the range of 98.80–102.94%. The plausible reason for color change is also discussed. The proposed method is simple, rapid, specific and highly selective with good precision.

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