Sensitive detection of tamsulosin hydrochloride based on dual-emission ratiometric fluorescence probe consisting of amine-carbon quantum dots and rhodamine B.

In this work, amine-carbon quantum dots (CQDs)/rhodamine B (RhB) ratiometric fluorescent (RF) sensor was employed for effective and selective determination of tamsulosin hydrochloride (TMS) based on a dual-emission fluorescence system. Although the function of amine-CQDs is to transfer the specific interaction between TMS and sensor into detectable fluorescence (FL) signals, RhB as a reference unit has been employed to omit internal and external effects. The FL signal was quenched by adding the TMS at 442 nm; nevertheless, it did not change at 569 nm. The material characterization and investigation of the sensing mechanism were done. The optimization of pH, the volumetric ratio of CQDs to RhB, and interaction time parameters were carried out by the one-variable-at-a-time (OVAT) method. The quantitative analysis of the concentration of TMS for this RF sensor in a linear range of 0.446-7.083 µg mL-1 (1.091-17.338 µM) was obtained (R2 = 0.9969, n = 3) under optimum conditions. The limit of detection and quantitation values were estimated to be 0.033 µg mL-1 (0.081 µM) and 0.109 µg mL-1 (0.267 µM), respectively. The repeatability of intra-day and inter-day were less than one percent. This inexpensive RF probe was well applied to determine TMS in biological fluids, and acceptable achievements were obtained.

A novel hybrid fluorescence probe sensor based on metal-organic framework@carbon quantum dots for the highly selective detection of 6-mercaptopurine.

In the present study, MIL-101(Fe) and amine-carbon quantum dots (CQDs) were combined via a post-synthetic modification (PSM) method; thus, a novel MIL-101(Fe)@amine-CQD hybrid fluorescent probe sensor for the detection of 6-mercaptopurine (6-MP) was synthesized. Amine-CQDs as a fluorescent material can convert the bonding interaction between MIL-101(Fe) and 6-MP into recognizable fluorescence signals, and MIL-101 (Fe) as an adsorbent can pre-concentrate 6-MP. Hereupon, this new sensor demonstrates high selectivity and sensitivity towards the detection of 6-MP. The addition of 6-MP to this probe quenches the fluorescence signal at 599 nm. In this study, factors such as pH, response time, and concentration of MIL-101(Fe)@amine-CQDs were optimized by the one-factor-at-a-time (OFAT) method. Under optimal conditions, the relationship between the fluorescence enhancement factor and the concentration of 6-MP for this sensor in the range of 0.1667-1.0000 µg L-1 was linear (R2 = 0.9977, n = 3). The limit of detection and limit of quantitation were 55.70 ng L-1 and 202.06 ng L-1, respectively, which are better than similar techniques. The repeatability of intra-day and inter-day was 2.4% and 4.7%, respectively. This fluorescent sensor was employed to determine 6-MP in real samples and exhibited acceptable results.