RoHS spectrometers (mostly based on X-ray fluorescence spectroscopy technology) may be affected by various interference factors during detection. The core interference types and elimination techniques are as follows:
1、 Spectral interference: spectral line overlap and non absorption line interference
Interference performance:
When the absorption lines of coexisting elements in the sample are close to the wavelength of the analysis line of the measured element, there will be overlapping or partial overlap of the absorption lines, resulting in higher absorbance; If the non absorbing lines emitted by the light source fall within the spectral passband, it will reduce the detection sensitivity.
Exclusion techniques:
Adjust analysis line: Select an undisturbed alternative analysis line for measurement.
Reduce slit width: By narrowing the spectral passband, multiple emission spectral lines are obscured, but the impact of noise needs to be balanced.
Software calibration: Using built-in algorithms such as background subtraction and peak fitting to separate overlapping spectral lines, such as using high-resolution energy dispersive detectors to distinguish adjacent element characteristic peaks.
2、 Physical interference: Sample non-uniformity and matrix effects
Interference performance:
Uneven coating, chemical treatment, or material on the surface of the sample can lead to differences in the distribution of elements in the detection area; The matrix material (such as polymer and inorganic material layering) may affect the fluorescence signal intensity due to self absorption effect.
Exclusion techniques:
Optimize sample preparation: Ensure that the sample surface is flat and free of coating, or homogenize the composition through grinding, dissolution, and other methods.
Matrix matching: Establish a calibration curve using standard substances with similar composition to the sample matrix, or compensate for the influence of the matrix using the standard addition method.
Control the detection area: Choose an appropriate spot size (such as 1-5 microns) to avoid errors caused by local concentration differences.
3、 Environmental interference: temperature, humidity, and electromagnetic fields
Interference performance:
High or low temperatures may affect equipment stability, and high humidity can easily cause internal high-voltage units to arc discharge; Electromagnetic interference (such as motors and high-frequency welders) can damage the spectrum or cause equipment failure.
Exclusion techniques:
Environmental control: Maintain room temperature at 20-25 ℃, relative humidity below 70%, and equip with air conditioning and dehumidification equipment.
Isolation installation: Install equipment in an area without electromagnetic interference, or use shielded cables to reduce external influences.