Latent fingerprint detection and visualization remains a challenge especially where problems of poor contrast, auto-fluorescent surfaces and patterned backgrounds are encountered. As a result there is an increasing interest in the development of simple, cost effective, rapid and yet accurate methods for latent fingerprint detection and recovery. Herein, this paper reports the synthesis of bright blue photoluminescent carbon dots (C-dots) via an eco-friendly and simple one-step microwave-assisted carbonization of potato peels’ biomass. The C-dots were prepared in only 3 min and ground into powder and used without any further treatment. The as-prepared C-dots were characterized using atomic force microscope, Fourier transform infra-red spectroscopy and X-ray diffraction with an average size of 1.0[Formula: see text]nm. The optical properties of the as-prepared C-dots were studied by UV-Vis spectroscopy and spectrofluorometer which established an excitation and emission wavelengths of 390[Formula: see text]nm and 480[Formula: see text]nm, respectively. Owing to their strong solid state fluorescence, the as-prepared C-dots’ powder was successfully used in latent fingerprint detection and imaging on porous and nonporous surfaces. Latent fingerprints were recovered with high resolution and excellent quality providing sufficient details for individual identification. These findings demonstrate that C-dots derived from biomass have a great potential in latent fingerprint analysis for forensic applications.

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The quest for the design and synthesis of carbon dots with anti-counterfeit properties that are derived via green, environmentally friendly and economical procedures is a continuous process. Carbon dots (C-dots) derived from biowaste are cheap to synthesize, possess good photo-stability and high synthetic yield, making them applicable in the anti-counterfeiting of currency. Herein, we report a novel eco-friendly, cheaper, and faster method for the synthesis of carbon dots with strong photoluminescence properties from monkey orange fruit (Strychnos spinosa) biowaste. The presence of the hydroxyl and carbonyl functional groups of the carbon dots were determined by the Fourier transform infrared spectroscopy (FTIR). The carbon dots showed strong blue emission fluorescence (emission wavelength of 452[Formula: see text]nm) when excited at 330[Formula: see text]nm. The morphology and size were determined by the atomic force microscopy (AFM) which indicated amorphous and spherical nanoparticles with an average size of less than 2[Formula: see text]nm. The no-crystallinity of the as-prepared carbon dots was confirmed using X-ray diffraction which showed the graphite-like structure. The carbon dots were produced and demonstrated good photo and chemical stability as well as high covert properties. The anti-counterfeiting of currency application by the synthesized carbon dots was demonstrated when the subsequent gel ink printed on the currency showed excellent chemical stability when exposed to washing with water, ethanol, and acetone. It also showed superior photostability when exposed to UV light at 365[Formula: see text]nm and daylight for an extended period of up to 6[Formula: see text]h. This work provides a facile, economical, and green approach for large scale production of carbon dots from the abundant biowaste.

Purpose Home-made alcohol-related deaths are a significant public health issue which is often overlooked. To date, approximately 30 people have died following the consumption of home brewed alcoholic beverages in Botswana. The process of brewing such alcoholic beverages remains unmonitored and makes it difficult to pinpoint the cause of these deaths. Ethanol content in these beverages is thought to be high and therefore contributing towards the deaths. The aim of this research was to develop and validate a method for the quantification of ethanol in the different types of home-brewed alcoholic drinks of Botswana. Methods Twenty-six different samples of home-brewed alcoholic drinks were collected from local brewers in different districts of Botswana. A Liquid–Liquid Extraction-Gas Chromatography-Flame Ionization Detector method was optimized for extraction of ethanol using ethyl acetate and validated for accuracy, precision, repeatability, selectivity, linearity, limit of detection, limit of quantification, stability. Following this, the method used to measure the concentration of ethanol in the different home brewed beverages. Results The method demonstrated linearity in the concentration range of 2.5–60% v/v with correlation coefficient (R 2 ) of 0.996 and, was found to be precise with %RSD values ≤ 5%. Repeatability was acceptable with %RSD values ≤ 5%. Percentage recoveries were within 100%. No interference was observed from likely excipients commonly found in home brewed alcoholic beverages, demonstrating good selectivity. Limits of detection and quantification were found to be 0.37% v/v and 1.12% v/v respectively. The analysed samples were discovered to contain ethanol with concentrations ranging from 2.56 to 36% v/v. Conclusion A method for the quantification of ethanol in home-made alcoholic beverages of Botswana was developed and validated. It is simple, cheap, rapid and does not require sophisticated instruments.