Preparation of standard gases for the occupational health

Objective This article introduced the application of the general methods for preparation of standard gases.Our study aimed to combine professional preparation method of standard gas with daily lab preparation method of comparative samples,to ensure the accuracy and precision of standard gases. Methods Different standard materials and different preparation methods were used to prepare the standard gas of vinyl chloride,and the precision and uncertainty of different methods by using the same detection method of GBZ/T 160.46-2004 was compared. Results The intra-day precision and inter-day precision of the mass flow ratio dynamic volumetric method was 3.79%-5.64% and 8.54%-9.63%,respectively.The combined uncertainty of this method is lower than 1.6%.The inter-day precision of the method with same dilution ratio were less than that of the syringe gas distribution method. Conclusion The stability of the mass flow ratio dynamic volumetric method was better than the syringe gas distribution method.The standard gas preparation method combining with the definite value standard gas and mass flow ratio dynamic volumetric method can ensure the standard development process and the data accuracy stability in the process.