In the case of dual-wavelength setting, the light of interfering substances generally has light scattering and non-specific light absorption, so it is necessary to set the main wavelength and sub-wavelength, and the main wavelength is the characteristic absorption peak of the substance to be tested. The principle of sub-wavelength setting is that the absorption of interfering substances at the main wavelength is as close as possible to the absorbance of the sub-wavelength. The same absorption peak, so it can eliminate the interference of hemoglobin. Therefore, the closer the primary wavelength and secondary wavelength of the interferer are, the better.
Measurement requirements
1. Sample: serum, urine, cerebrospinal fluid, etc.
2. Reagents: single reagent, double reagent
3. Dual wavelength: two wavelengths composed of the main wavelength and the sub-wavelength. Interference in the detection process can be eliminated.
4. Calibrator (standard): Compare the concentration of unknown samples
5. Quality control material: used for monitoring the status of instruments, reagents, etc. in the daily work of the biochemical instrument.
method
1. End-point method (endessay) is completely converted into products, and the reaction is no longer carried out to reach the end point, and the absorbance of the reaction end point is taken to calculate the concentration of the tested substance. In biochemical tests, except for enzymes, BUN, and CRE, end-point methods are used for detection.
1). One-point end point method: take the absorbance of a point when the reaction reaches the end point to calculate the result.
2). Two-point endpoint method: take the absorbance of one point before the reaction has started, and then take the absorbance of the second point when the reaction reaches the end point. Calculate the result by subtracting the absorbance at the second point minus the absorbance at the first point. Mainly used to subtract reagents and sample blanks. Guarantee the accuracy of the results. Generally used for double reagents.
2. Fixed time method (two-point method): It is to take the difference between two points still in the reaction to calculate the result. These two points are neither the starting point nor the end point of the reaction. Mainly used to detect some non-specific items, such as creatinine.
3. Continuous monitoring method (kinetic method, rate method): When measuring enzyme activity or enzyme metabolites, the absorbance value (△; A/min) that changes linearly in the reaction curve is continuously taken to calculate the result. It is also called a zero-order reaction because the absorbance difference between the points is zero during the linear reaction time.
