Saturation of air with oxygen is a new method of high-temperature flame atomic absorption spectral analysis used in the WFX-110 BRAIC spectrometer (No. 29191-05 in the State Register of Measuring Instruments). It is environmentally friendly and, moreover, is economical and convenient to use.
The most common are two types of flame atomic absorption spectral methods:
1. atomic absorption using an air-acetylene flame
2. atomic absorption using a nitrous oxide-acetylene flame
The temperature of the flame air - acetylene is only 2300C. Therefore, AAS with an air-acetylene flame can only be used for the analysis of elements of the first group, with low melting and boiling points and an oxide dissociation energy of less than 5 eV. These elements include: alkali metals, a copper subgroup, a zinc subgroup, as well as Mn, Fe, Co, Ni, Pb, etc.
For elements of the second group with average melting and boiling points and an oxide dissociation energy approaching 5 eV, such as alkaline earth metals, Cr, Mo, Ga, Ge, Sn, etc., this method can only be of limited use due to low atomization efficiency and serious chemical interference.
For elements of the third group with high melting and boiling points and oxide dissociation energy exceeding 6 eV: rare earth elements, titanium subgroup, subgroup V, as well as W, B, Al and Si, atomic absorption using an air-acetylene flame is practically not used.
The flame temperature of nitrous oxide - acetylene can reach 2950C, which is 650C higher than the flame temperature of air-acetylene. Therefore, AAS based on this method is quite successfully used to analyze elements of the second group. Nitrous oxide - acetylene flame can also be used for elements of the third group with high melting and boiling points and high oxide dissociation energy in order to expand the analyzed range to 70 elements.
However, to maintain this type of flame, a large amount of toxic nitrous oxide (another name for laughing gas, used in medicine for anesthesia) is used. The consumption of this gas is very high, and the cost is high, it is difficult to obtain gas in small towns and in remote regions. The temperature of the nitrous oxide - acetylene flame cannot be adjusted, which does not allow achieving the best atomization efficiency for a number of elements. This flame also produces intense molecular absorption due to combustion products such as CN, making highly sensitive measurements of some elements impossible.

The key point in increasing the sensitivity of the flame atomic absorption method and reducing chemical interference is the increase in flame temperature, possible with an increase in the oxygen content in the air and free control of the flow rates of all gas components.
Flame atomic absorption method of oxygenated air - acetylene is a new patented new method (patent no. 92101560.7). Its principle is to add pure oxygen to the air and then mix it with acetylene. The flow of all gases is accurately controlled by flowmeters. The optimum flame setting for the best atomization efficiency can also be easily set. This cheap and highly sensitive method of high temperature flame atomic absorption spectral analysis is completely safe for health.
Since the flame temperature can be adjusted by controlling the flow rate of acetylene and oxygen (up to 3100 - 3150 C), the method is applicable to the measurement of various elements. For elements of the first group, the method of spectral absorption air - acetylene can be directly applied without the addition of oxygen. For elements of the second group, such as Ca, Sr, Ba, Eu, Yb, Mo, Ga, Sn, the sensitivity of the oxygen-saturated air-acetylene flame method is about 10 times higher than that of the air-acetylene and nitrous oxide-acetylene flames. . For elements of the third group, the sensitivity is the same as when using nitrous oxide.