Abstract: By processing a lead cover at the top of the measuring chamber with an injection hole, the Chiang automatic liquid scintillation counter is converted into a liquid scintillation counter modified by a luminescence analyzer. It can measure the luminous intensity and measure the ray, and the measurement of the ray performance is not change. The measurement performance of the luminous intensity has a good correlation with the dedicated illuminating analyzer, and the sensitivity is higher than that of the dedicated illuminating analyzer.
Key words: luminescence analyzer; liquid scintillation counter
At present, luminescence analysis technology has been more and more widely used in the fields of biomedicine, and various special luminescence analyzers have also been introduced, but the price is relatively expensive. A liquid scintillation counter for oral ray measurement is actually the measurement of the luminescence of a scintillator under the action of a ray, which is a stable and multiphoton event]. Biochemical luminescence is generally transient and is a single photon event whose luminescence value reaches a maximum at the moment the reactants contact each other and then rapidly decreases. Therefore, direct measurement of biochemiluminescence using a liquid scintillation counter is limited.
We have modified the measurement chamber of the liquid scintillation counter. The modified liquid scintillation counter can be loaded as easily as a dedicated illuminating analyzer, which solves the problem that the liquid scintillation counter cannot be measured in time and is used for biochemiluminescence measurement.
1 Materials and methods
Open the top cover of FJ-2115 automatic liquid scintillation counter (manufactured by Xi'an 262 Factory), remove the lead cover on the top of the measuring chamber, install the specially processed lead cover with injection holes, and add black rubber washer to avoid Light penetrates. The additive measurement method was selected, and the modified device was tested by luciferase ATP luminescence system: 1 luciferase (Shanghai Institute of Plant Physiology, Chinese Academy of Sciences) was formulated into a concentration of 3.5 mg/ml with NaOH-glycine buffer. The ATP standard (B.M., Germany) was diluted with Tris-HCl buffer to a standard concentration of 1 x 10 -8 mol/L, 1 x 10 mol/I, ... 1 x 10 -11 mol/L. 3 Add 200 uL of each standard solution to the light-emitting tube. 4 After the light tube is sent to the measurement room. 800 uL of luciferase solution was injected from the injection hole, and the luminescence value N of 6 s was measured.
2 results
2.1 luminescence measurement
The 6s luminescence value Ni of each standard solution is subtracted from the background value No, and the logarithm is obtained: Yi=lg(Ni-No), and the concentration c is taken as a logarithm: Xi=lgCi, Yi is the ordinate, Xi Plot for the abscissa (Figure 1).
The measurement results of FJ-2115 have a good correlation with the measurement results of LKB-1251 (light emission analyzer manufactured by LKB, Sweden) (r=098), and the sensitivity of FJ-2115 is slightly higher than LKB1251.
2.2 Stability
The same concentration of ATP was repeatedly measured 20 times with IKB1251 and modified FJ-2ll5 liquid scintillation counter, and the errors were 7.8 and 8.1, respectively. The results were similar. There was no significant difference.
2.3 The effect of modified FJ-2115 on B-ray feedback
Before the modification. The measurement efficiency of H is 51.2%. The background is 15 CPM, the quality factor is 58.25. The conversion efficiency of H is 51.1, the background is 48 CPM, and the quality factor is 54.4.
3 Discussion
The liquid scintillation counter is a special instrument for measuring p-rays. There are two photomultiplier tubes, which are in accordance with the measurement method (that is, the signals are given when two photocells have signals at the same time. Otherwise, there is no signal output). If it is used to measure single photon events such as biochemical luminescence, then an additive measurement is required, so that the measurement efficiency is higher than that of a single photomultiplier tube, and the noise signal is also Increased. In this study, the automatic liquid scintillation counter was converted into a luminescence analyzer capable of timely measurement and timely measurement. The measurement performance is similar to that of a dedicated luminescence analyzer, and some indicators are better than the dedicated luminescence analyzer. Play a multi-functional role, and have a liquid scintillation count without increasing investment.
The unit of the device provides a convenient study of chemiluminescence analysis. The modified liquid scintillation counter can also measure p-rays.
(Source: Huazhong University of Science and Technology Xu Shunqing Zhang Liping Shu Bohua)
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