Operando on-line monitoring of nanoplastics in real environmental water samples enabling an optical microfiber Mach-Zehnder interferometer

Nanoplastics pose a great threat to ecological water environments, especially for ocean water, lake water. Small-sized nanoplastic particles can enter into animal and plant bodies easily. Therefore, operando on-line quantification of nanoplastics in real environmental samples can bring a big challenge for early-stage water pollution testing and warning. Conventional nanoplastic particles detection technologies didn’t provide enough high sensitivity and accuracy due to their complicated and time-consuming sample pre-treatment procedures. To overcome these limitations, an optical microfiber was applied to detect nanoplastics in some real environmental samples. Owing to high sensitivity and superior specificity of the sensor, it could detect target polystyrene (PS) nanoplastics with sizes of 150 nm and 100 nm in pure water and mixture solution, realizing ultra-low limit-of-detections (LODs) of 1.23×10 −6 mg/mL, 1.41×10 −6 mg/mL and 2.31×10 −6 mg/mL, 2.96×10 −6 mg/mL, respectively. More importantly, such an optical device could also successfully recognize PS nanoplastics in collected lake, ocean, and wastewater samples. Thus, our proposed approach could open up a novel and advantageous way for operando on-line monitoring of nanoplastics in real water samples.