VALERALDEHYDE: METHOD 2536, Issue 2, dated 15 August 1994 - Page 4 of 5 EVALUATION OF METHOD: Atmospheres were generated by injection of valeraldehyde with a syringe pump into a heated block injector and flash vaporizer into a stream of air at 80% ± 5% RH flowing at a fixed rate. The generator and sampling manifold system have been described previously [5]. Concentration of valeraldehyde vapor was independently verified by the 2,4-dinitrophenylhydrazine procedure of Lipari and Swarin [3] or by monitoring with an AID Model 590 organic vapor monitor. Breakthrough studies of valeraldehyde at 100 ppm, conducted at 75 and 50 mL/min flow rates, gave 5% breakthrough at 170 min and 280 min, respectively. The method was evaluated over the range of 9 to 374 mg/m 3 using 12-L samples. Desorption efficiencies from statically-spiked samples average 102.5% (89.2-126.6%) for the range 2 to 508 µg/sample. No bias with dynamically-generated samples was observed with the method when samples were collected at 40 mL/min and below. When samples were collected at ca. 60 mL/min, a negative bias of approximately 20-30% was observed. Samples were found to be stable for at least 4 weeks when stored at room temperature.
REFERENCES: [1]
[2] [3]
[4] [5]
Kennedy, E.R., Y.T. Gagnon, J.R. Okenfuss and A. Teass. "The Determination in Air of Selected Low-Molecular Weight Aldehydes as Their Oxazolidines by Capillary Gas Chromatography," Appl. Ind. Hyg., 3(10), 274-279 (1988). NIOSH Manual of Analytical Methods, 3rd. ed., U.S. Department of Health and Human Services (1984), Method #2531. Lipari, F., and S. J. Swarin. "Determination of Formaldehyde and other Aldehydes in Automobile Exhaust with an Improved 2,4-Dinitrophenylhydrazine Method," J. Chromatog ., 247, 297-306, (1982). The Merck Index, 11th ed., Merck & Co., Rahway, NJ (1989). Kennedy, E.R. and R.H. Hill, Jr. "Determination of Formaldehyde in Air as an Oxazolidine Derivative by Capillary Gas Chromatography," Anal. Chem. 54, 1739-1741 (1982).
METHOD REVISED BY: Yvonne T. Gagnon and Eugene R. Kennedy, Ph.D., NIOSH/DPSE.
APPENDIX A: SYNTHESIS OF 9-BUTYL-1-AZA-8-OXABICYCLO[4.3.0]NONANE: Place a solution of purified 2-(hydroxymethyl)piperidine (1.15 g; 10 mmol) in 20 mL of toluene in a 100mL round-bottomed flask. Use several 2-mL portions of toluene to rinse residual 2(hydroxymethyl)piperidine from the container used for weighing. Add anhydrous magnesium sulfate (2.0 g) to the flask to dry the valeraldehyde solution as it is added and to remove the water which forms during the reaction. Add a solution of 0.947 g valeraldehyde (11 mmole) in 20 mL of toluene to the 2(hydroxymethyl)piperidine solution dropwise with stirring over 1 h. (NOTE: Excess aldehyde was added to ensure complete conversion of 2-(hydroxymethyl)piperidine to oxazolidine.) Stir the solution overnight, then filter to remove the magnesium sulfate. Remove the toluene from the solution at reduced pressure (1 mm Hg) by rotary evaporation. The product is a pale yellow viscous oil, ca. 90 to 95% pure by gas chromatography. Store the oxazolidine at 0 °C to prevent decomposition. Mass spectral data for 9-butyl-1-aza-8-oxabicyclo[4.3.0]nonane: m/e with relative intensities in parenthesis, 182 (7.0%), 152 (4.6%), 126 (100%), 110 (11.3%), 98 (37%). IR data (Vapor phase @ 280 °C) for this compound in cm -1 with relative intensity in parenthesis are: 2945 (s), 2874 (m), 2781 (m), 1455 (w), 1383 (w), 1339 (w), 1265 (w), 1203 (w), 1133 (m), 1075 (w), 1028 (m).
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94
