In the compliance testing of electronic and electrical products, the ROHS2.0 directive has increasingly strict requirements for the restriction of hazardous substances. To ensure precise compliance, modern laboratories no longer rely on a single technology, but instead build an efficient and accurate detection system through the synergistic application of X-ray fluorescence spectroscopy (XRF) and wet chemical analysis. The combination of these two technologies achieves a seamless transition from rapid screening to precise confirmation.
XRF Spectroscopy: The 'Gatekeeper' for Efficient Screening
Handheld or desktop XRF spectrometers are the first line of defense for ROHS testing. The core technology lies in using X-rays to excite the characteristic fluorescence of elements in the sample, thereby enabling rapid and non-destructive qualitative or semi quantitative screening of elements such as cadmium (Cd), lead (Pb), mercury (Hg), total bromine (Br, used to calculate PBBs/PBDEs).
Its huge advantage lies in:
Extremely fast: results can be obtained within tens of seconds, suitable for initial screening of large quantities of samples.
No pre-treatment required: can directly inspect finished products and components without damaging the product.
On site availability: Handheld XRF can be used for real-time screening in warehouses, production lines, and other locations, greatly improving efficiency.
Through XRF screening, "negative" or "low-risk" samples can be quickly identified, while "high-risk" samples that exceed or approach the limit can be marked, providing targets for more accurate wet chemical analysis in the future.
Wet Chemistry Method: The "Chief Judge" for Accurate Judgment
When XRF screening finds that the bromine (Br) content exceeds the standard or cannot accurately determine trace amounts of Cd and Pb, wet chemistry method must be activated as a confirmation method. Its core technologies include inductively coupled plasma spectroscopy (ICP-OES/MS), gas chromatography-mass spectrometry (GC-MS), etc.
The essence of this process lies in the complex sample pretreatment:
Dissolve: Use strong acid to dissolve the solid sample and convert the substance to be tested into liquid form.
Extraction and Purification: Separate and purify target organic compounds (such as PBBs, PBDEs) from the matrix using specific chemical solvents.
The core value of wet chemistry method lies in:
Absolute quantification: providing accurate and error free concentration data, with legal arbitration effect.
Morphological analysis: It can clearly distinguish whether total bromine comes from harmless flame retardants or restricted PBBs/PBDEs, which XRF cannot achieve.
Extremely low detection limit: For the strictly limited cadmium (0.01%) in ROHS 2.0, wet chemistry method can provide detection accuracy and reliability far beyond XRF.
Collaborative Efficiency Enhancement: Building an Optimal Testing Process
The collaboration between the two is not simply a superposition, but a scientific workflow of "XRF rapid screening → target locking → wet chemical method precise confirmation" has been constructed. This collaborative mode balances the two major requirements of efficiency and accuracy: XRF, as an efficient "scout", avoids the expensive and time-consuming comprehensive testing of all samples by wet chemical methods;
In summary, in ROHS2.0 compliance testing, XRF spectroscopy and wet chemistry methods are not in competition, but rather complementary golden partners. A deep understanding and effective collaboration of these two core technologies is the key to improving detection efficiency, ensuring product compliance, and avoiding market risks for enterprises.