Analysis of formic acid in air samples.
Am Ind Hyg Assoc J 1978 Feb; 39(2):151-153
A method for the determination of airborne formic-acid (64186) was described. Air samples were drawn through a midget impinger containing 15 milliliters of 0.1 normal sodium-hydroxide (1310732) at a sampling rate of 1 liter per minute for 42 minutes. Derivatizing solution, containing a mixture of ethanol (64175) and sulfuric-acid (7664939), was then added to an aliquot taken from the impinger, and sealed in a gastight reaction vial. After 2 hours, the ethyl-formate (109944) vapor which was formed in the headspace in the vial was analyzed by gas chromatography. The quantity of ethyl-formate was proportional to the quantity of formic-acid in the vial. The advantages and disadvantages of headspace analysis were discussed. Although the percent recovery of this procedure was not investigated since it involved the reaction of a strong base with a moderately strong acid, the reaction was assumed to go to completion. The author concludes that the method was precise for the determination of formic-acid in air at 0.1 of threshold limit value of 9mg/m3, with a relative standard deviation of 11 percent.
NIOSH-Author; Analytical-methods; Carboxylic-acids; Chromatographic-analysis; Gas-chromatography; Threshold-limit-values; Alcohols; Formates; Acid-base-equilibrium; Analytical-chemistry
64-18-6; 1310-73-2; 64-17-5; 7664-93-9; 109-94-4
American Industrial Hygiene Association Journal