Lead testing made easy with handheld X-ray fluorescent (XRF) analyzer
Several health hazards associated with lead has been a well established concern. Added to it, with the recent maggi noodles controversy and its ban over the issue of excess lead content in it, has left everyone awestruck. Following maggi, few other products were also brought under the scanner by Food Safety and Standards Authority of India (FSSAI).Though laboratories are well equipped with techniques and instrumentation to measure lead to confirm legal regulatory compliance. However, lab analyses are not immediate and tend to be expensive and time-consuming. Hence, the newly introduced hand held X-ray fluorescent (XRF) analyzers have made lead testing easy.
Handheld X-ray fluorescent (XRF) analyzers have the capability to quantify or qualify nearly any element like lead, magnesium, uranium etc, depending on specific instrument configurations. Portable XRF spectrometers allow you to take the battery operated analyzer to the sample rather than bringing the sample into the lab. This is especially useful when the test specimen is large or heavy.
How the XRF analyzer works? An x-ray beam with enough energy to affect the electrons in the inner shells of the atoms in a sample is created by an x-ray tube inside the handheld analyzer. The x-ray beam is then emitted from the front end of the handheld XRF analyzer.
The x-ray beam then interacts with the atoms in the sample by displacing electrons from the inner orbital shells of the atom. This displacement occurs as a result of the difference in energy between the primary x-ray beam emitted from the analyzer and the binding energy that holds electrons in their proper orbits; the displacement happens when the x-ray beam energy is higher than the binding energy of the electrons with which it interacts. Electrons are fixed at specific energies in their positions in an atom, and this determines their orbits. Additionally, the spacing between the orbital shells of an atom is unique to the atoms of each element, so an atom of potassium (K) has different spacing between its electron shells than an atom of gold (Au), or silver (Ag),or Lead(Pb) etc.
Electrons have higher binding energies. Therefore, an electron loses some energy when it drops from a higher electron shell to an electron shell closer to the nucleus. The energy lost can be used to identify the element from which it emanates, because the amount of energy lost inthe fluorescence process is unique to each element. The individual fluorescent energies detected are specific to the elements that are present in the sample.
The entire fluorescence process occurs in small factions of a second. A measurement using this process and a modern handheld XRF instrument can be done in seconds. The actual time required for a measurement will depend on the nature of the sample and the levels of interest. High percentage levels will take a few seconds while part-per-million levels will take a few minutes.The XRF analyzer is available at the NRCLPI, Bengaluru centre and it is very user friendly said Mr Vinay Kumar C, Environmental Researcher, National Referral Centre for Lead Projects in India (NRCLPI), Bengaluru.