high power graphite electrode
Classification of high power graphite electrode
1. According to the heating method: longitudinal heating high power graphite electrode, transverse heating high power graphite electrode
2. According to performance points: ordinary high power graphite electrode (non-pyrolysis) is suitable for low temperature (≤2000℃) atomized elements such as silver, cadmium and lead; pyrolysis high power graphite electrode is suitable for low, medium and high temperature (>2500℃) Atomized elements; the platform high power graphite electrode is suitable for medium and low temperature (≤2400℃) atomized elements. Series of atomic absorption graphite atomizers have the characteristics of high sensitivity and long service life. In the spirit of localization of imported instrument accessories, we have used graphite materials to develop high power graphite electrodes since 1979 to replace imported high power graphite electrodes. Based on many years of experimental research results, the high power graphite electrode is developed using high purity, high density and high strength graphite materials. Its test performance indicators are basically the same as those of imported foreign high power graphite electrodes of the same type, and the sensitivity and service life are better than those of foreign countries. Imported high power graphite electrode.
Three categories of high power graphite electrode
high power graphite electrode, as the name implies, is a graphite product made of high-purity graphite powder through a specific process. Atomic absorption spectroscopy is established based on the fact that the ground state atoms of the measured element in the gaseous state have a strong absorption effect on the element’s atomic resonance radiation. This method has the advantages of low detection limit, high accuracy, good selectivity, and fast analysis speed. It is mainly suitable for the analysis of trace and trace groups in samples. Among them, high power graphite electrode is the core of graphite furnace analysis.
Classification of high power graphite electrode There are three types of high power graphite electrodes commonly used now, high density high power graphite electrode, pyrolysis high power graphite electrode and platform high power graphite electrode.
Heating methods are divided into: vertical heating high power graphite electrode, horizontal heating high power graphite electrode.
High-density high power graphite electrode is made of ordinary graphite, which is widely used. It is suitable for the determination of low atomization temperature and easy formation of volatile oxides.
Pyrolysis high power graphite electrode analyzes the elements that are easy to combine with carbon, the main component of the high power graphite electrode (elements that easily form carbides). Typical elements are Ni, Ca, Ti, Si, V and Mo. In the high-density high power graphite electrode, the sample easily penetrates into the graphite, resulting in a larger contact area between the element to be measured and the carbon. In the pyrolysis-coated high power graphite electrode, due to the small contact area, the formation of carbides is suppressed, thereby improving the sensitivity.
Platform high power graphite electrode is suitable for low, medium and high temperature atomization elements, especially Ni, Cu, Ca, Ti, Sr and other elements, which are 10-30 times more sensitive than ordinary high-density high power graphite electrodes. The change in acidity has a greater impact on the sensitivity of the pyrolysis tube. With the platform high power graphite electrode, different heating procedures can be used to reduce the influence of liquid sample properties on the analysis to a minimum. This is because the atomized atoms in the platform high power graphite electrode are not easy to recombine, unlike ordinary high power graphite electrodes, which tend to exist in the low temperature area in the center of the tube due to the heat of the tube wall. Even the concentration of acid varies greatly. In addition, timely selection of the atomization signal can avoid producing background signals. Therefore, this is an effective method for analyzing complex matrix samples, such as biological samples, wastewater, and seawater.