Application of Total Reflectance Fluorescence Analyzer (TXRF) in Soil Trace Heavy Metal Monitoring (2)

(5) Instrument analysis operation

(1) X-ray tube parameter setting.

Figure 5-3 Light tube parameter setting

Figure 5-4 Example of X-ray spectrum

(2) Set the angle of the position of the sliding table and the height of the sliding table.

(3) The measurement time is the spectrum scan time.

(4) After confirming that all parts of the instrument are working normally, the measurement process can be started

(5) Start the nitrogen switch (when nitrogen environment is needed)

(6) Turn on the X-ray tube

(7) Start collecting atlas

(8) Save the map

(6) Quantitative analysis

At present, when using the TXRF product prototype to test liquid samples, the test mass concentration range of low-range samples is 0～1mg/L, and the test mass concentration range of high-range samples is 1～10mg/L.

1.

Put the cleaned quartz glass slide into the sample chamber of the instrument, perform a 600s test according to the test conditions recommended by the instrument, and save the obtained spectrum as a blank glass slide of the instrument

2.

Take out the blank glass slide after the test is completed, select a 10mL volumetric flask and add 400uL of 1000mg/L yttrium nitrate internal standard solution, and dilute to 10mL with distilled water as the reagent blank standard solution

3.

Take out the reagent blank glass slide after the test, use a specific cleaning method to complete the cleaning, prepare a 1mg/L multi-component standard sample plus internal standard test: Measure 400uL of 1000mg/L yttrium nitrate solution into a 10mL volumetric flask, use The volume of 1mg/L multi-component standard sample is adjusted to 10mL

4.
Multi-element analysis and calculation

After completing the qualitative analysis of the spectrum, a multi-element analysis of the spectrum is required
.
Click "multi-element analysis" to pop up the multi-element analysis and calculation operation interface, select the corresponding target in the "calculate peak area" operation column
.

In the "Blank atlas" operation bar, the blank atlas of the glass slides that have been tested must be loaded, and the slide blanks are subtracted by the three buttons of "Smooth Blank", "Blank Curve" and "Subtract Blank"
.
After the blank spectrum is subtracted, click the "Calculate" button to calculate the area of ​​the opened spectrum, and give the ratio of the characteristic peak area of ​​each element to the peak area of ​​the internal standard and the correlation coefficient k
.

5.
Mass concentration calculation

After completing the analysis of the elements in the standard sample map and establishing the relevant curve, the elements in the map need to be analyzed.
The main task is to select the elements for which the standard curve needs to be established and enter the standard sample mass concentration value
.

Click the "Curve Calibration" option in the "Quantitative Analysis" of the main menu bar, enter the mass concentration of the multi-component standard sample in the calibration interface, and then select the element that needs to be calibrated
.
Calibration and calculation use the Y element as the internal standard element, so the internal standard option is Y, which is used as a parameter for establishing the curve
.

After the calculation is completed, close the multi-element analysis interface, click the "quantitative analysis" button in the main menu bar, select the "mass concentration calculation" option, open the calculation mass concentration operation interface, and enter the project name, sample number and other detailed information in the interface.
The integration time, test voltage, and test current system are automatically saved for users according to the map
.

(7) Matters needing attention

(1) The instrument emits X-rays during measurement
.
During the measurement, please do not open the case of the instrument or the door of the sample chamber, otherwise it may be exposed to X-ray radiation
.

(2) During the use of the instrument, if smoke or peculiar smell or abnormal noise is emitted from the instrument, please stop using it immediately
.

(3) Without radiation safety protection measures, please do not repair, modify, or disassemble the instrument privately
.

(4) Avoid placing the instrument in damp, dust, water, etc.
places, otherwise it will easily cause leakage and fire
.

(5) Avoid using the instrument in places subject to vibration or tilt
.

(6) Please stop using the test room window if it is damaged
.
Otherwise, it is easy to cause radiation pollution and malfunction
.

(7) The instrument is a precision instrument, so avoid excessive shaking or impact
.

(8) It is recommended to use under the conditions of an ambient temperature of 10～30℃; the power supply is within AC220V±10%; the instrument needs to be stable for 10min after the power is turned on
.