Ten NIOSH Analytical Methods - Crag Herbicide I.
NIOSH 1979 Apr:20 pages
The NIOSH validated method for the determination of 2,2,4- dichlorophenoxy-ethanol (136787) (natrium) is described. Ninety liters of air (flow rate at 1.0 to 1.5 liters per minute) is drawn through a mixed cellulose ester membrane filter. Natrium is extracted from the filter with 10 milliliters (ml) of deionized water. One ml of the solution is added to a separatory funnel containing 25ml of methylene-blue solution, 0.05 grams (g) methylene- blue chloride plus 50g anhydrous sodium-sulfate plus 10ml concentrated sulfuric-acid per liter, and 50ml chloroform. After shaking, the chloroform layer is removed and the absorbance is measured in a spectrophotometer at the wavelength of 650 nanometers. The concentration is determined by comparison with a calibration curve obtained by analyzing standards containing natrium concentrations of 0.1 to 3 times the OSHA standard of 15 milligrams per cubic meter (mg/m3). Storage stability tests are conducted in which samples are analyzed immediately or 7 days after collection. A sample loss of 4.9 percent occurs. The working range of the method is 1.5 to 45mg/m3 natrium. The standard deviation is
NIOSH-Author; NIOSH-Analytical-Method; Analytical-Method; Standards; Sampling; Standards-Completion-Program; SCP; Set-7; Colorimetry; Herbicides;
NTIS Accession No.
Division of Physical Sciences and Engineering, NIOSH, U.S. Department of Health and Human Services, Cincinnati, Ohio, 20 pages, 5 references