. . . . . . . "EPA method study 24, method 601 : purgeable halocarbons by the purge trap method"@en . . "EPA method study 24, method 601 purgeable halocarbons by the purge trap method"@en . . "Purgeable halocarbons by the purge trap method"@en . . . "EPA method study twenty-four, method 601"@en . . . . .