Natural gas is bought and sold based on its energy content and volume. The energy content is usually determined by calculations utilizing gas chromatographic (GC) analysis in combination with physical constants. The energy content or heating value is expressed in British Thermal Units (BTU). The energy value for a specific volume of natural gas is derived by multiplying the BTU data and the gas volume expressed in standard cubic feet. The result is expressed in MMBTU or dekatherms. The GC analyses are also used to correct the flow rate data for compressibility. Therefore, errors in analysis of the gas impact the total heating value in two ways, initial BTU determination and corrected flow rate. One of the largest sources of analysis error is improper sample conditioning. Most of the difficult problems associated with sample conditioning stem from either the presence of liquid in the source gas or condensation occurring in the sample conditioning system. This presentation will address both of these problems