How to remove chemical interference from flame photometer?

How to remove chemical interference from flame photometer? Chemical interference refers to the interference effect caused by the chemical interaction between the element to be tested and other components in the process of converting the sample solution into free radical atoms
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Chemical interference is a selective interference, which depends not only on the properties of the element to be tested and coexisting elements, but also on the type of flame, flame temperature, flame state and observation location
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So how do you remove chemical interference from flame photometers? To analyze specific samples, elements to be tested and experimental conditions, some methods are listed below for reference! 1.
Using high temperature flame The flame temperature directly affects the melting, evaporation and dissociation process of the sample.
Many interferences that appear in the low temperature flame can be partially or removed in the high temperature flame
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For example, in the determination of calcium in an air-acetylene flame, when there is a phosphate radical, it forms a stable calcium pyrophosphate with calcium and interferes with the determination of calcium
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The presence of sulfate interferes with the determination of calcium and magnesium
.

These interferences can be removed if the N2O-acetylene flame is used instead
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2.
Using the flame atmosphere For elements that are easy to form refractory and non-volatile oxides, such as silicon, titanium, aluminum, beryllium, etc.
, if a flame with strong reducibility is used, it is conducive to the atomization of the elements and significantly improves the sensitivity
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Due to the different temperatures and regions of the flame, the degree of interference at different observation heights is also different.
By selecting the observation height, the interference can also be reduced or eliminated
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 　　3.
Add release agent Commonly used release agents are lanthanum chloride, strontium chloride and so on
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 　　Note: The amount of release agent added
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Only a certain amount of release agent can be added to release, but it is also possible that the absorption signal will be reduced due to the addition of too much.
The amount of addition should be determined through experiments
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 　　4.
The action mechanism of adding protective agent The protective agent is as follows: The protective agent acts with the element to be tested to form a stable complex, preventing the formation of non-volatile compounds between the interfering element and the element to be tested; The protective agent and the interfering element form a stable complex and To avoid the formation of non-volatile compounds between the element to be tested and the interfering element; the protective agent forms their own complexes with the element to be tested and the interfering element to avoid the formation of non-volatile compounds between the element to be tested and the interfering element
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 　　For example, using EDTA as a protective agent to inhibit the interference of phosphate on calcium belongs to the mechanism; using 8-hydroxyquinoline as a protective agent can inhibit the interference of aluminum to magnesium belongs to the mechanism; using EDTA as a protective agent can inhibit the interference of aluminum to magnesium.
three mechanisms
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 　　In addition: glucose, sucrose, ethylene glycol, glycerol have all been used as protective agents
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It should be pointed out that the use of organic protective agents makes the analyte easier to atomize because the organic complex is easier to dissociate
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 　　5.
Add buffer Add an excessive amount of interfering element to both the sample and the standard solution, so that the interference effect will not change, but inhibit or interfere with the influence of the element on the measurement result.
This interfering substance is called a buffer
.

 　　For example, when calcium is determined, a considerable amount of Na and K are added to the sample and standard solution, which can affect the influence of Na and
K.

The amount of buffer added should be greater than the low limit of interfering elements that will not change the absorption value
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Applying this method tends to significantly reduce sensitivity
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 　　If the composition of the sample is determined by comparison 6.
Adding flux Ammonium chloride has a sensitizing effect on many elements
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It suppresses the interference of aluminum, silicate, phosphate and sulfate
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 　　The sensitization of the absorption signal of the element to be measured has three effects: (1) The melting point of ammonium chloride is low, it melts quickly in the flame, and it has a fluxing effect on some high-melting points to be measured; (2) Chloride Ammonium has a high vapor pressure, which is conducive to the refinement of droplets and melting evaporation; (3) the presence of chloride increases the tendency of the element to be tested to be converted into chloride, which is conducive to atomization
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 　　7.
Combined use of anti-interference agent Aluminum interferes with magnesium
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Interference can be reduced and recovery improved if release and protectant are used in combination
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With EDTA as protective agent, the recovery rate can be improved
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The effect of lanthanum as release agent is more obvious than that of EDTA
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Using glycerol and perchloric acid as protective agents, the effect is between EDTA and lanthanum
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Magnesium can also be recovered quantitatively if lanthanum (1 mg/mL), glycerol (10%), and perchloric acid (0.
1 M) are used in combination with aluminum concentrations up to 1000 ug/mL
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 　　The above is the relevant introduction about removing chemical interference of flame photometer.
I believe that everyone has a corresponding understanding of this after reading, and everyone can use it as a reference.
I hope you can help
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