CN201273879Y - Apparatus for fluorescent testing pesticide residue by imaging method - Google Patents

Abstract

The utility model discloses a device for fluorescently detecting pesticide residues by an imaging method, which comprises an ultraviolet light source, and a low-pass filter, a lens, and a color separation film inclined at 45° to the optical axis are installed in the optical path at the rear end of the ultraviolet light source. The sample is placed in the reflected light path at the front end of the film, and two lens groups with a magnification of 1 are installed in the fluorescent reflected light path of the sample at the back end of the color separation film. A diaphragm is installed between the two lens groups. Array CCD detector. Based on the principle of fluorescence analysis that has been widely studied in recent years, the fluorescence detection uses an area array CCD detector to detect the fluorescence intensity of the background area and the target area, and at the same time obtains the geometric shape of the target, and eliminates the ultraviolet light through image processing and smoothing the contour. Instability factors brought by test papers and reagents can be used to obtain the relative changes in the fluorescence intensity of the target area, compared with the standard to determine the content of pesticide residues, which can avoid the interference of fluorescence and improve the sensitivity and accuracy of detection.

Description

A device for fluorescent detection of pesticide residues by imaging method

technical field

The utility model belongs to a detection technology, in particular to a device for detecting pesticide residues using imaging method fluorescence.

Background technique

So far, there are many detection techniques for components. Most of the initial techniques use volumetric and colorimetric analysis based on the chemical properties or structural characteristics of the components. Problems such as impurity interference and low sensitivity are not easy to solve. From the 1980s to the present, advanced instruments such as gas-liquid chromatography, high-performance liquid chromatography, and gas-mass chromatography have been widely used for analysis, which have good specificity and high sensitivity, but require professional operation, long analysis cycle, expensive equipment, and difficult for the basic level. Promotion is also not conducive to on-site monitoring. Fluorescence detection of components, such as the detection of pesticide residues, uses ultraviolet excitation light, test paper, visual observation, or photoelectric sensor measurement. Due to individual subjectivity, unstable reagents, low component content, and unstable fluorescence intensity, this detection method leads to unstable background fluorescence intensity of the test paper. These factors lead to high randomness in the detection results and cannot effectively identify residual components. Whether the content exceeds the standard or not, resulting in missed detection and false positives.

Utility model content

The purpose of this utility model is to provide a device for the fluorescence detection of pesticide residues by imaging method, based on the principle of fluorescence analysis widely studied in recent years, the fluorescence detection adopts the area array CCD detector to detect the fluorescence intensity of the background area and the target area At the same time, the geometric shape of the target is obtained, and the instability factors caused by the ultraviolet lamp, test paper, and reagent are eliminated through image processing and contour smoothing, so as to obtain the relative change of the fluorescence intensity of the target area, and compare it with the standard to determine the pesticide residue The content can avoid the interference of fluorescence and improve the sensitivity and accuracy of detection.

The technical scheme of the utility model is as follows:

A device for fluorescent detection of pesticide residues by imaging method, including an ultraviolet light source, a low-pass filter, a lens, and a color separation film inclined at 45° to the optical axis are installed in the optical path at the rear end of the ultraviolet light source, and the reflection light path at the front end of the color separation film is The sample is placed, and two lens groups with a magnification of 1 are installed in the fluorescent reflection light path of the sample at the back end of the color separation film. A diaphragm is installed between the two lens groups. The outgoing light of the lens groups is imaged on the area array CCD detector.

The imaging fluorescence detection device is characterized in that the two lens groups with a magnification ratio of 1 are symmetrical structures.

The utility model adopts the principle of fluorescence analysis method to make specific pesticide components on the test paper emit fluorescence through ultraviolet light excitation, and judge whether the pesticide exceeds the standard by measuring and analyzing the background, sample intensity and geometric characteristics.

Compared with the existing method, the utility model has the characteristics of high sensitivity, simple and fast method, and less sample demand. In the state of reagent lack of stability, through the relative fluorescence intensity measurement, the automatic detection of the fluorescent spot area of the test paper and the background of the test paper Identification, so that it can quickly and accurately judge whether the amount of pesticide residues exceeds the standard, and can make on-site inspections in corresponding occasions, and show unique advantages in the field of environmental monitoring.

Description of drawings

Fig. 1 is a structural diagram of the optical path of the present invention.

Fig. 2 is a flow chart of computer processing of fluorescence imaging of reagents.

Detailed ways

See attached picture. A device for fluorescent detection of pesticide residues by imaging method, including an ultraviolet light source 9, a low-pass filter 8, a condenser lens 7, a color separation film 1 inclined at 45 degrees, and a color separation film 1 are installed in the optical path at the rear end of the ultraviolet light source The sample is placed in the reflection light path at the front end, and the lens group 2, 3, diaphragm 4, lens group 5, 6 are installed in the fluorescence reflection light path of the sample at the back end of the color separation film 1, and the outgoing light of the lens group 5, 6 is imaged on the area array CCD detector. The ultraviolet illumination light path and the fluorescence detection light path are coaxial, and a 45-degree color separation film is used to separate the illumination light path and the fluorescence detection light path; the ultraviolet illumination light path is designed to form an illumination spot; the fluorescence detection light path is designed to form a 1:1 imaging, to detect the fluorescence spot area, and the light path The stray light is designed to be less than 5%, and the fluorescence detection uses an area array CCD detector for imaging.

The light emitted by the ultraviolet light source 9 passes through the condenser lens 7 and is reflected by the color separation film 1 to form a spot of a certain size to illuminate the sample. A low-pass filter 8 is added to the light source to transmit only ultraviolet light; Enough illuminance and lighting uniformity. The sample fluorescence passes through lenses 2, 3, diaphragm 4, lenses 5, 6, and is imaged on the area array CCD detector at a ratio of 1:1. The system is a fully symmetrical system. The aberration measured in the vertical axis direction of this system is the vertical The left and right halves of the axial aberrations have opposite signs, so these aberrations are zero after the full combination. It eliminates all primary aberrations except curvature of field.

The computer software transmits the image collected by the area array CCD detector to the computer through the usb port and displays it in real time; Part of the gray value of the corresponding image is integrated, and the integrated value is compared with the threshold value determined through experiments in advance to determine whether the pesticide exceeds the standard.

Claims (2)

1, a kind of device of imaging method fluoroscopic examination residues of pesticides, include ultraviolet source, be equipped with in the light path of ultraviolet source rear end low pass filter, lens, with the color separation film of 45 ° of inclined light shafts, be placed with sample in the color separation film front end reflected light path, magnification be installed be two lens combination of 1 in the fluorescent reflected light path of color separation film rear end, between two lens combination diaphragm is installed, the emergent light of lens combination images in the area array CCD detector.

2, imaging method fluorescence detection device according to claim 1 is characterized in that described magnification is that two lens combination of 1 are symmetrical structure.

Images