GLUTARALDEHYDE: METHOD 2531, Issue 2, dated 15 August 1993 - Page 5 of 5 B. SYNTHESIS OF GLUTARALDEHYDE OXAZOLINE: Place a solution of purified 2-(hydroxymethyl)piperidine (0.57 g, 5 mmol) in 10 mL of toluene in a 50-mL round-bottomed flask. Several 2-mL portions of toluene can be used to rinse residual 2(hydroxymethyl)piperidine from the container used for weighing. Add magnesium sulfate (2.5 g) to the round-bottomed flask to dry the glutaraldehyde solution as it is added and to remove the water which forms during the reaction. Add a solution of 1 mL of 25% aqueous glutaraldehyde e(0.25 g, 2.5 mmol) in 10 mL of toluene to the 2-(hydroxymethyl)piperidine solution dropwise with stirring over 1 hr. Stir the solution overnight, then filter to remove the magnesium sulfate. Remove the toluene from the solution at reduced pressure by rotary evaporation. The product is a yellow viscous oil, ca. 90 to 95% pure. NOTE: Exact amounts of reagent are required for this synthesis since excess glutaraldehyde can cause appreciable formation of the mono-oxazolidine derivative of glutaraldehyde.
C. SORBENT PREPARATION (optional if commercially prepared tubes are used: Extract 4 h in Soxhlet with 50/50 (v/v) acetone/methylene chloride. Replace with fresh solvent and repeat. Vacuum dry overnight. Add 1 g purified 2-(hydroxymethyl)piperidine in 50 mL toluene for each 9 g extracted XAD-2 sorbent. Allow this mixture to stand 1 hr with occasional swirling. Remove the solvent by rotary evaporation at 37 °C and dry at 130 kPa (1 mm Hg) at ambient temperature for approximately 1 hr. To determine the amount of background for each batch, extract several 120-mg portions of the coated sorbent with toluene and analyze (steps 7 through 13). No blank peak is expected for glutaraldehyde.
D. DESORPTION EFFICIENCY: The determination of desorption efficiency (DE) is not necessary when using the calibration procedure in step 10. If desired, the following procedure can be used to determine DE: a. Prepare and analyze a set of glutaraldehyde oxazolidine standard solutions (step 9.1) and a set of working standards (step 10), including media blanks. b. Treating the working standards as unknowns, read the mass (µg) of oxazolidine found in each working standard (W), and in the average media blank (B). c. Using the mass of glutaraldehyde, µg, spiked onto the working standard (W o) and the stoichiometric conversion factor between glutaraldehyde and glutaraldehyde oxazolidine (2.94), calculate the desorption efficiency:
d.
Prepare a graph of DE vs. µg glutaraldehyde recovered per sample
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/93
