Section 761.253 - Chemical Analysis(a) Select applicable method(s) from the following list to extract PCBs and determine the PCB concentration from the standard wipe sample collection medium: SW-846 Method 3540C, Method 3550C, Method 3541, Method 3545A, Method 3546, or Method 8082A (all standards incorporated by reference in § 761.19 ). Modifications to the methods listed in this paragraph or alternative methods not listed may be used if validated under Subpart Q of this part or authorized in a § 761.61(c) approval.(b) Report all PCB sample concentrations in [MICRO]g/100 cm2 (16 square inches) of surface sampled. If sampling an area smaller than 100 cm2, report converted sample concentrations in accordance with §761.243(b).