Code of Federal Regulations Title 43. Public Lands:  Interior § 43.3175.114 Spot samples—allowable methods

(1) Purging—fill and empty method. Samples taken using this method must comply with GPA 2166–05, Section 9.1 (incorporated by reference, see § 3175.30);

(2) Helium “pop” method. Samples taken using this method must comply with GPA 2166–05, Section 9.5 (incorporated by reference, see § 3175.30). The operator must maintain documentation demonstrating that the cylinder was evacuated and pre-charged before sampling and make the documentation available to the AO upon request;

(3) Floating piston cylinder method. Samples taken using this method must comply with GPA 2166–05, Sections 9.7.1 to 9.7.3 (incorporated by reference, see § 3175.30). The operator must maintain documentation of the seal material and type of lubricant used and make the documentation available to the AO upon request;

(4) Portable gas chromatograph. Samples taken using this method must comply with § 3175.118;  or

(5) Other methods approved by the BLM (through the PMT) and posted at www.blm.gov.