Progress of Atomic Fluorescence Spectrometer in China

The atomic vapor absorbs light emitted by a light source having a characteristic wavelength and is excited to transition to a high energy state, and then deexcites a transition to a lower energy state (usually the ground state) and emits an atomic fluorescence of a characteristic wavelength. The method of measuring the fluorescence intensity and then obtaining the content of the test element in the sample is called atomic fluorescence spectroscopy (AFS).

In 1970, the development of multi-channel atomic fluorescence spectrometers was started. The instrument developed includes a pulsed hollow cathode lamp, a rotating interference filter disc, a Cassegrain reflex system, a flame cell, and a logic circuit for measuring the fluorescence of each metal element, allowing the simultaneous determination of six elements. In 1981, for the first time, Americans combined hollow cathode lamps as atomic fluorescence excitation light sources with ICP atomization systems to develop the world's first HLC-ICP-AFS commercial instrument. This device has the ability to analyze multiple elements simultaneously, with simple spectral lines and a wide linear range.

At the end of the 1970s, many science and technology workers in China began to study atomic fluorescence spectroscopy and made contributions. In 1976, Du Wenhu and others successfully developed the Cold Atomic Fluorescence Mercury Analyzer and measured the trace mercury in food, soil, minerals, and rocks. In 1977, Shanghai Metallurgical Research Institute developed a high-intensity hollow cathode lamp as an excitation light source for dual-channel non-dispersive dispersion. Atomic fluorescence spectrophotometer for determining elements such as manganese, zinc and cadmium in aluminum alloys, copper alloys, zinc alloys, spheroidal graphite cast irons and alloy steels. In 1979, Guo Xiaowei et al. successfully developed a hydride non-dispersive atomic fluorescence spectrometer using bromide electrodeless discharge lamps as the excitation light source. Trace elements such as arsenic, antimony and bismuth in minerals and rocks were determined. Based on this, Guo Xiaowei, Zhang Jinmao, and others collaborated in 1981. A two-channel hydride atomic fluorescence spectrometer was developed that allows the simultaneous determination of two hydride-forming elements. In 1988, the Beijing Geological Instrument Factory, the Northwest Institute of Nonferrous Geology, and the Institute of Geophysical and Geochemical Exploration of the Ministry of Geology and Mineral Resources jointly developed a dual-channel hydride-atomic fluorescence analyzer using a characteristic hollow cathode lamp as an excitation light source and computer-controlled instrument functions and data processing. Using a dedicated mercury gas measurement device, a detection limit as low as 0.0078 ng of mercury was obtained.

Hydride generation atomic fluorescence spectrometry is a new combination analysis technique. It concentrates the advantages of the two methods: The use of hydride generation technology to separate the elements to be measured from most of the matrix elements. The resulting hydride can be atomized in an argon-hydrogen flame, whereas the argon-hydrogen flame itself has a high Fluorescence efficiency and lower background; the fluorescence wavelengths of all hydride elements and mercury are located in the ultraviolet region; the combination of these factors makes it possible to produce a simple-structured, non-dispersive atomic fluorescence analyzer that obtains arsenic, antimony, bismuth, selenium, tellurium. Lower detection limits of lead, tin, antimony, and mercury. The method is characterized by high sensitivity, good reproducibility, low spectral interference, wide linear range, fast analysis speed, and low cost.

The hydride generation atomic fluorescence spectrometry developed in China for more than a decade has its own characteristics. And the scientific research results have rapidly transformed into productivity. Many domestic factories have successively produced various types of hydride atomic fluorescence spectrometers. Under the efforts of the majority of analysts, HG-AFS has been widely used in various fields. At present, the main light sources used in HG-AFS in China are microwave-activated stepless discharge lamps and pulse-powered special hollow cathode lamps. According to incomplete statistics, the total output has exceeded a thousand units and has been exported to Canada, Iran and other countries. HG-AFS has become an indispensable and important analysis method for various analytical technologies. It is an essential instrument for many laboratories.