Simultaneous colorimetric sensing of malachite & leucomalachite green in aquatic products based on novel ionic associate self-visualization HPTLC strips

•A new thin-layer chromatographic (TLC) visualization methodology was developed.•Novel self-visualization nanomaterial was successfully synthesized.•The ionic associate self-visualization is achieved on high-performance TLC strips.•Malachite green (MG) and leucomalachite green can be analyzed in aquatic products.•The method is easy to operate and sophisticated equipment is not needed. The development of simultaneous and rapid screening of the residues of veterinary drugs and their metabolites is up to now still a challenge. In this study, a novel strategy of read-out analysis is proposed based on high-performance thin-layer chromatography (HPTLC) separation coupled with self-visualization detection of trace of leucomalachite Green (LMG) and malachite green (MG) in aquatic products. The novel self-visualization nanomaterial was successfully synthesized and subsequently fully characterized. The ionic associate MG–I3 formed on the visualization sensing interface was effectively attested by MALDI-TOF/TOF-MS for the first time. A serials of visualization reactions were conducted on the target zone surface of HPTLC after separation. Under the optimum conditions, the calibration curves of LMG and MG were obtained with good linearity in the range of 0.25–8.0 μg mL−1 and 0.125–4.0 μg mL−1, respectively. The limits of detection and limit of quantification were calculated as 1.71 and 5.19 μg kg−1 for LMG and 0.9 and 2.74 μg kg-1 for MG, respectively. Real sample analysis and validation provided satisfactory results. The proposed method has the potential to detect simultaneously, rapidly, and accurately LMG and MG in aquatic products during storage, handling, and sales.