This International Standard specifies a method for the determination of the time-weighted average mass concentration of lithium hydroxide (LiOH), sodium hydroxide (NaOH), potassium hydroxide (KOH), and calcium dihydroxide [Ca(OH)2] in workplace air by collection of the particulate hydroxides on a filter and analysis of the corresponding cations using ion chromatography.
For aerosol sampling, the method is applicable to the personal sampling of the inhalable fraction of airborne particles, as defined in ISO7708, and to static (area) sampling.
The method is applicable to the determination of masses of 0,005mg to at least 2,5mg of lithium per sample and 0,01mg to at least 5mg of sodium, potassium, and calcium per sample.
The concentration range of particulate LiOH, NaOH, KOH, and Ca(OH)2 in air for which the measuring procedure is applicable is determined by the sampling method selected by the user. For a 1m3 air sample, the working range is approximately 0,002mgm−3 to at least 20mgm−3 for all four hydroxides. For a 30l air sample, the lower limit of the working range is approximately 0,1mgm−3 for all four hydroxides.
The procedure does not allow differentiation between the hydroxides and their corresponding salts if both are present in the air. If the cations are present alone in the form of hydroxides, the method is specific for these basic compounds. In other circumstances, the results obtained represent the highest concentration of the hydroxides that could be present in the sampled air. (See 12.6.)