Both Ultraviolet-Visible and Double Monochromatic Fluorescence Dual Detector for High Performance Liquid Chromatography

摘要

The present invention relates to an innovative analyzing and detecting instrument with excellent sensitivity and stability, especially to a present art that realizes the initiation of the dual-purpose instrument in a small inner-casing which combines both ultraviolet-visible and double monochromatic fluorescence dual detector widely used in the high performance liquid chromatography by taking the first to use deuterium lamp as the individual light source of the dual detectors, the individual sample detection cell and the individual electrical circuit, providing two detectors for detecting and analyzing, and emphasizing the advanced automatic gain art adopted in the present invention to make sure the main technical targets of the whole wavelength range are integral, easy to be checked up, and can solve the existing worldwide technical problem of sensitivity-stability exclusion of the two detectors only with the combination of the double techniques in both automatically eliminating noise and reducing drift, so that the excellent technical performance can be achieved.

主权项

1. The both ultraviolet-visible and double monochromatic fluorescence dual detector for HPLC, characterized in that: the casing of power supply socket is set and on the said casing set a sample solution inlet and an outlet, a control panel with operation keyboard and liquid crystal display, and a detection signal output interface, the detection optical member and the detection electromechanical member are set inside the casing;
The said detection optical member: including a first monochromatic spectroscopic device—raster G1 used for both ultraviolet-visible wavelength and fluorescence excitation wavelength, a second monochromatic spectroscopic device—raster G2 used for secondary fluorescence emission wavelength, a light source, four groups of lens needed for processing the light paths, two groups of photosensitive diode for receiving ultraviolet and fluorescence photoelectric signals respectively, and a individual sample detection cell shared by the ultraviolet and fluorescence detection which is connected with the said sample solution inlet and outlet; The said detection electromechanical member: connecting with the said operation keyboard and the liquid crystal display of the control panel, negative terminals of the two photosensitive diodes of the said ultraviolet monochromator and the fluorescence monochromator which are used to receive photoeletrical signals are parallel connected, the earthed positive terminal controlled by the central controller through shift switch of the first relay, and the negative terminals of two photosensitive diodes connected with the inverting input terminal of the first operational amplifier in the preposed amplifying module; Preposed amplifying module: including a first operational amplifier whose two input terminals are connected with the parallel connection junctions of the negative terminal of photosensitive diode and the earth respectively, the first output terminal connected with the fixed head of the other shift switch of the first relay, the two shift switches which are mutually synchronized, the two resistances maintaining feedback and corresponding to working state of the ultraviolet and fluorescence detection respectively, converting the input photocurrent signals into voltage signals in the preposed amplifying module and then amplifying them; Auto gain module: at first, the analogy method of using photomultiplier as receiving components of photoelectrical signals is successfully adopted to impose the input photocurrent of the preposed amplifier on the increase or reduction of the negative high voltage of the photomultiplier through the control of the central controller composed of microcomputers, so that the whole wavelength range of voltage in the first output terminal of the automatically controlled preposed amplifier can achieve the designed constant value to realize the auto gain purpose; the present invention gives full play to the microcomputer digital operation's advantages of quickness, accurateness, and non-interference by using a digital method: including analog/digital-digital/analog convertor 1 and digital/analog convertor 2, and as the central controller composed of microcomputers operates in a digital method, the analog voltage signal of the first output terminal of the preposed amplifying module will be input into the auto gain module and be amplified and subtracted digitally by the analog/digital-digital/analog convertor 1 controlled by the said central controller, and when it is used for ultraviolet detection, the voltage of the output terminal of the analog/digital-digital/analog convertor 1 for every wavelength should be controlled in a constant value in the whole wavelength range; the central controller deposits the digital signals of the analog/digital-digital/analog convertor 1 in the digital/analog convertor 2, and conducts subtraction to the two digital signals in dynamic state and in static state in digital/analog convertor 2; Noise processing module: including a second operational amplifier whose in-phase input terminal is connected with the output terminal of the analog/digital-digital/analog convertor 1, after the central controller makes subtraction to the two digital signals in dynamic and static state in digital/analog convertor 2, the convertted different voltage of the output terminal of digital/analog convertor 2 will be transmitted randomly to the inverting input terminal of the second operational amplifier to be used for the elimination of the noise and drift of the instrument; Logarithm amplifying module: the input terminal of the logarithm amplifying module is connected with the said second output terminal of the second operational amplifier, and the position of the shift switch of the second relay is driven by the said central controller, and during the ultraviolet detection period, the third operational amplifier and double transistor Tr1 and Tr2 will conduct logarithm processing, and the fourth operational amplifier will conduct the amplifying and output operation; during the fluorescence detection period, the voltage signals of the output terminal of the second operational amplifier of the noise processing module are directly amplified through the fourth operational amplifier and then the amplified sample voltage signal is output through the detection signal output interface.