IR characterization of plant leaves, endemic to semi-tropical regions, in two senescent states.

We are developing a robust and economic electro-optical remote sensing methodology to monitor the state of health and hydration of trees, endemic to subtropical regions. We measured reflectance spectra with Fourier transform infrared (FTIR) of three samples of two different oak trees. We find that spectral bands suitable for monitoring the state of the health and senescence of the oak include intervals around 0.9 µm and 1.8 µm. The easiest and the most cost-effective strategy would be to implement an electro-optical remote sensing radiometric system featuring a commercial camera incorporating a traditional charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) detectors and a wideband transmission filter, from about 0.8 to 1 µm.

N-doped oxidized carbon dots for methanol sensing in alcoholic beverages.

Methanol (MeOH) adulteration in alcoholic beverages resulting in irreparable health damage demands highly sensitive and cost-effective sensors for its quantification. As carbon dots are emerging as new biocompatible and sustainable light-emitting detectors, this work demonstrates the hydrothermally prepared nitrogen-doped oxidized carbon dots (NOCDs) as on-off fluorescent nanoprobes to detect MeOH traces in water and alcoholic beverages. The presence of 1% of MeOH in distilled water is found to decrease the NOCD fluorescent emission intensity by more than 90% whereas up to 70% ethanol (EtOH) content changes the signal to within 20% of its initial value. HR-TEM analysis reveals the agglomeration of the nanoprobes suspended in MeOH. Due to their selectivity towards MeOH, the fluorescent nanoprobes were successfully tested using a few MeOH spiked branded and unbranded Mexican alcoholic beverages. Varying degrees of signal quenching is observed from the fluorescent nanoprobes dispersed in different pristine beverages with a detection limit of less than 0.11 v%. Herein, we establish a new perspective towards economically viable non-toxic fluorescent probes as a potential alternative for the detection of MeOH in alcoholic beverages.