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• A new fluorescence method was developed for the MPD determination. • The proposed method had a wide linear range of 10–600 μg L−1. • A low detection limit of 4 μg L−1 was obtained. • The method was successfully applied for detecting MPD in real samples. This work presented a new fluorescence method for the determination of m-phenylenediamine (MPD) based on the reaction between MPD and acetylacetone. The formed compound Hacac-MPD exhibited strong blue fluorescence emission under 365 nm excitation. Its fluorescence intensity had an excellent correlation with the MPD concentration Under the optimal conditions, the developed method gave a linear range of 10–600 μg L−1 with a low detection limit of 4 μg L−1. Furthermore, the coexistence of common inorganic ions and other aromatic amines had hardly influence on the determination of MPD, demonstrating high selectivity. Additionally, the MPD in spiked water samples and hair dye samples was successfully detected by the developed method, and the recoveries were 97.5%-101.6% and 98.3%-98.9%, respectively. The established method exhibited a good application prospect for the determination of MPD in environment and daily necessities. [ABSTRACT FROM AUTHOR]

• A UV image detection system was designed for rapid visual detection of UV absorption gas. • It consisted of a high quantum efficiency UV camera, multiple different wavelength filters and gas regulators. • The UV images of SO 2 were obtained at different concentrations and temperatures. • The detection limit for SO 2 was as low as 4 ppb. We demonstrate a multi-wavelength ultraviolet (UV) imaging detection system for gaseous pollutants with absorption characteristics in the UV band. As a proof of concept, the detection of sulfur dioxide (SO 2) was used as an example to develop a method based on UV imaging. The critical component of the system is a highly sensitive CCD array (1024 × 1024 pixels) UV camera with high quantum efficiency (QE) in the UV range (>30% transmission at 200–240 nm, >50% transmission at 240–400 nm), multiple different wavelength bandpass filters (270 nm, 280 nm, 300 nm, and 310 nm for SO 2), environmental condition controller (temperature range 278–318 K, relative humidity range 35–85%), and a compact and robust design (362 mL of the gas absorption cell with a 4.2 m optical path length). The advantages of this system are convenient, fast, and can realize visualization. The system was applied for detecting SO 2 in various conditions (different concentrations, temperatures, and humidity). After optimization, the detection limit for SO 2 detection is 4 ppb, and the uncertainty of concentration measurement is only about 2.7%. [ABSTRACT FROM AUTHOR]