What is the allowable error range for the chemical test of the sulfur analyzer
Release time: 2025-12-12 views: 92
The allowable error range for sulfur analyzers in laboratory tests needs to be determined based on specific application fields,national standards,or industry standards.Generally,the allowable error(or tolerance)is related to the sulfur content level,sample type,and the precision grade of the instrument.The following are some common reference standards:
1.Allowable error for sulfur analyzers in coal testing
According to the Chinese national standard GB/T 214-2007"Determination of Total Sulfur in Coal",the allowable differences for different methods are as follows:
▶Ashing method(reference method):
Repeatability limit:When the sulfur content St,ad≤1.50%,the tolerance is 0.05%;when St,ad>1.50%,the tolerance is 0.10%
Reproducibility critical difference:When the sulfur content St,ad≤1.50%,the tolerance is 0.10%;when St,ad>1.50%,the tolerance is 0.20%
▶Coulometric titration method(commonly used in automated sulfur analyzers):
Repeatability limit:The same as the ashing method.
Reproducibility critical difference:The same as the ashing method.
In actual laboratory tests,internal quality control in the laboratory usually requires that the relative deviation of repeated measurement results does not exceed 5%(when the sulfur content is low,the absolute deviation may not exceed 0.02%).
2.Allowable error for sulfur determination in petroleum products
For example,GB/T 380-1977"Determination of Sulfur Content in Petroleum Products"or ASTM D4294(X-ray fluorescence method):
When the sulfur content is low(such as<0.05%),the tolerance may be±0.002%or the relative deviation≤10%.
When the sulfur content is high(such as>1%),the tolerance may be±0.05%or the relative deviation≤5%.
3.General principles for environmental monitoring or industrial analysis
•Low sulfur samples(sulfur content<0.1%):The allowable absolute error is usually between 0.01%and 0.02%.
•Medium to high sulfur samples(sulfur content 0.1%-5%):The allowable relative error is usually 3%-5%.
•High sulfur samples(sulfur content>5%):The allowable relative error can be relaxed to 5%-10%.
4.Requirements for instrument calibration and quality control
Sulfur analyzers need to be calibrated regularly with certified reference materials(CRM),and the sulfur content of the CRM should be similar to that of the samples to be tested.
After calibration,the error in the determination of the CRM should be within the uncertainty range given in the CRM certificate.
During daily sample analysis,it is usually required that the absolute deviation of parallel sample determination results does not exceed the repeatability limit specified in the standard.
Key suggestions
1.Consult relevant standards:Be sure to look up the corresponding national standards(GB),industry standards(YB/HG,etc.)or international standards(ISO/ASTM)based on the sample type(coal,oil,ore,soil,etc.).
2.Instrument manual:Sulfur analyzer manufacturers usually provide the precision indicators of the instrument(such as repeatability,linear error,etc.),which can be used as a reference.
3.Laboratory certification requirements:Laboratories certified by CMA/CNAS need to verify and establish internal quality control limits based on standard methods.
If more specific error ranges are needed,please provide the type of sample and the approximate range of sulfur content for further reference to the corresponding standards.
This article is shared by Hebi Huanuo Coal Inspection Instrument,a manufacturer of coal testing instruments,for reference only.
Hebi Huanuo Electronic Technology Co.,Ltd.focuses on the research and production of coal element analysis instruments,including calorimeter,sulfur analyzer,ash volatile matter analyzer,moisture analyzer series,bonding index analyzer series,gel layer analyzer series,hydrogen analyzer series,industrial analyzer series,Hastelloy grindable analyzer series,ash melting point analyzer series,rotary drum machine series,crusher series,prototype machine series,etc.The product is widely used in industries and departments such as electricity,coal,metallurgy,petrochemicals,environmental protection,geology,cement,colleges and technical supervision,as well as coal laboratories.
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