Design of a 3D-printing fluorescence detector for HPLC separation: a prototype device

Herein, we developed a three-dimensional (3D)-printing fluorescence detector that could be connected to the HPLC system, and distinguished by its ease of assembly, cost-effectiveness, and high adaptability. The detector comprises a laser diode, a 3D-printing flow cell, quartz glass, a long-pass filter, a silicon phototube, and a voltmeter. Technically, the flow cell we designed here has a very compact structure, and it is convenient to embed the optical filter and the phototube, which is also a highlight of our detector to ensure the miniaturization of the whole device. Through the optimization of the detector's structural configuration, the adjustment of the various dimensions and relative positions of the detection window, and the removal of the metal encapsulation cover of the silicon phototransistor, we achieved the optimal detection sensitivity and stability. Experimental findings indicate that the 3D-printing fluorescence detector achieves a limit of detection (LOD) of 5 μg mL^-1, a linear detection range of 5-60 μg mL^-1, and exhibits reasonable inter-day and intra-day stability. Finally, the detector demonstrated its practical utility by successfully separating and detecting a mixed solution of rhodamine 6G and rhodamine B, underscoring its potential for real-world applications.