SJ/T 11141-2017Generic specification for LED displays (English PDF)

1 Scope

This Standard specifies the method for the determination of methanol content in developer for the electronics industry by headspace gas chromatography method.

This Standard is applicable to the determination of methanol content in developer for the electronics industry. The minimum detection concentration of methanol in this method is 1 mg/kg.

2 Normative References

The following documents are essential to the application of this document. For the dated documents, only the versions with the dates indicated are applicable to this document; for the undated documents, only the latest version (including all the amendments) are applicable to this document.

GB/T 602 Chemical Reagent - Preparations of Standard Solutions for Impurity

GB/T 6682 Water for Analytical Laboratory Use - Specification and Test Methods

GB/T 9722 Chemical Reagent - General Rules for the Gas Chromatography

3 Terms and Definitions

For the purpose of this document, the terms and definitions given in GB/T 9722 apply.

4 Principle of Method

In a closed bottle, at a certain temperature, methanol molecules escape from the liquid phase to the gas phase. After a certain period of time, the methanol molecules reach a dynamic equilibrium between the gas and liquid phases. At this time, the concentration of methanol in the gas phase is proportional to its concentration in the liquid phase. The methanol in the gas phase is separated by a capillary column and detected by a hydrogen flame ionization detector. The retention time is qualitative, and

6 Apparatus

7 Test

9 Detection Limit of the Method

Prepare the developer solution and developer solution quantitatively added 20mg/kg methanol standard solution; adjust the instrument to the best working state; measure the methanol content in the developer solution with/without adding methanol standard solution; meanwhile, continuously measure at least for ten times.

The detection limit is calculated by "DL", the value is expressed by "mg/kg", and calculated according to Formula (1):

Where:

C - The value of the concentration of methanol standard solution added to the developer, in (mg/kg) [c = 20];

S - The standard deviation of the peak height or peak area of methanol in the developer solution without adding the methanol standard solution;

S1 - The average peak height or peak area of methanol in the developer solution with adding the methanol standard solution;

S0 - The average peak height or average area of methanol in the developer solution without adding the methanol standard solution;

The standard deviation of the peak height or peak area of methanol in developer solution without adding the methanol standard solution, expressed in terms of “s”, and calculated by Formula (2):

Where:

xi – peak height or peak area of methanol in the developer with adding the methanol standard solution;

– average peak height or peak area of methanol in the developer without adding the methanol standard solution;

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