The photocatalytic effect of ZnO particles was developed for the detection of standard flunitrazepam and Rohypnol tablets in coloured spirit solution by a UV-Vis spectrophotometer. It is a screening technique for qualitative detection and quantitative estimating flunitrazepam concentration before getting the precise values by other high performance techniques. In an alcoholic solution with ZnO particles, the flunitrazepam is changed to 7-amino-flunitrazepam after irradiation. The absorption band shifts to a longer wavelength (309 nm to 345 nm). The photocatalytic parameters such as the reaction temperature, ZnO concentration, and irradiation time were studied in this work. With the optimum condition, the detection limits of standard flunitrazepam and Rohypnol are 0.024 mg/l and 0.092 mg/l in a solution mixture of ethanol and soda water (1:25). The method was applied to detect the flunitrazepam in coloured spirit brands in Thailand.

Directly analyzing an herbal drug and its contamination is crucial to avoid severe problems due to uncertain dosages and unwanted contaminants. This article describes the first example of a dosing-spoon-based sensor for point-of-use detection of an herbal extract and its contamination. Andrographis paniculata is an herbal drug conventionally used for the therapy of many symptoms and infectious diseases, including COVID-19. The developed device consists of a sensitive electrochemical sensor, enabling the detection of A. paniculata extract. The lab-on-a-spoon squarewave voltammetric system provides the detection result with favorable sensitivity and simplicity in a short time (less than 15 s). The calibration curve of the modeled herbal extract covers a range of 0.030–7.350 mg mL–1 with a limit of detection of 20 μg mL–1. The device and data analysis were applied for determining real samples of A. paniculata extracts. The developed device is sensitive for the screening of processed products from A. paniculata. Moreover, this single dosing-spoon-based sensor can also simultaneously screen the contamination of heavy metals (i.e., cadmium and lead). We envision that this lab-on-a-spoon demonstration would expand the scope of portable pharmaceutical and biochemical sensors, offering promising convenient screening tools for industrial and household applications.

Fipronil is a member of phenylpyrazole insecticide, which was widely used in agriculture to kill pests [1-2]. It can also form metabolite, such as fipronil sulfone by oxidation process, which is more toxic than parent compound [3-4]. Fipronil sulfone can persist for longer duration, which can easily bind to lipid-rich matrices and get into food chain [5]. Its contamination in foods gained more concerned recently [6] and many agencies have restricted fipronil content in various food like vegetables, fruits, water, grains, edible oil, meat, eggs, etc. Fipronil could damage our liver, kidneys, and thyroid glands [6]. It is said that fipronil toxicity has no particular antidote and can be harmful to pregnant, weak, and old people [9]. Fipronil’s toxicity and risk to human health demands reliable and sensitive analytical method to monitor and reduce contamination. Many adsorbents previously used were commercially available and costly. Considering these limitations, a new sorbent can be developed with locally available materials, which could be more reliable, sensitive, or decrease matrix interferences for determining fipronil and fipronil sulfone. This research also emphasis on advancing a reliable and green approach technique for tracing fipronil (F) and fipronil sulfone (FSO). So, the sorbent will be developed by using eco-friendly, cheap, locally available, and stable materials.