Synthesis of green emissive Plectranthus scutellarioides carbon dots for sustainable and label-free detection of phytohormone indole-3-acetic acid

Plectranthus scutellarioides is commonly known as painted neetle or coleus, and widely employed in the Indian Ayurveda for several medical applications. In this work, green light emitting carbon dots (CDs) were fabricated using Plectranthus scutellarioides extract. The synthesized Plectranthus scutellarioides CDs (PS-CDs), possess green fluorescence properties, which was confirmed by UV-lamp at 365 nm. The fluorescent PS-CDs exhibit a pronounced emission at 530 nm when excited at a wavelength of 450 nm. As synthesized probe was stable for 30 days and was having the quantum yield of 21.7 %. The probe was used for the qualitative determination of indole-3-acetic acid (IAA) hormone. The probe depicts a good limit of detection of 0.0421 µM with a linear range of 0.05–2.5 µM for IAA sensing. The real sample analysis was performed in vegetable samples, showing good recoveries, which were well agreed with high performance liquid chromatographic technique analysis.