Page:NIOSH Manual of Analytical Methods - 2532.pdf/4

 GLUTARALDEHYDE: METHOD 2532, Issue 1, dated 15 August 1994 - Page 4 of 4 Table 1.

Recovery and Stability Study of Glutaraldehyde Concentration (µg/sample) 1.2

Day Analyzed 1 42*

Recovery (%) 95 100

Sr .028 .014

2.4

1 42

97 98

.027 .034

12

1 42

96 98

.034 .023

A 20-point, 4-concentration curve was used to determine a LOD of 0.24 µg/sample and a LOQ of 0.78 µg/sample. No air samples were generated during this evaluation. Audit samples were prepared with liquid spikes of glutaraldehyde in water added directly onto the DNPH-coated silica gel tube. These audit samples were shipped, stored, and analyzed by an independent laboratory using this method. The results were acceptable with recoveries of about 100% at 1.2 µg per tube, 94% at 2.4 µg per tube, 85% at 12 µg per tube, and <0.3 µg per tube for the blanks [3]. REFERENCES: [1] [2] [3]
 * Samples stored at 25 C for 42 days.

OSHA Analytical Methods Manual, Glutaraldehyde, Method 64. OSHA Technical Center, Salt Lake City, UT. U.S. Dept. of Labor (1985). The Merck Index, 11th ed., Merck & Co., Rahway, NJ (1989). User Check, DataChem Labs, Sequence #7958-J (unpublished, 3/14/94).

METHOD WRITTEN BY: Charles E. Neumeister, NIOSH/DPSE, and Gordon Hill, DataChem Laboratories, Salt Lake City, UT. APPENDIX: PREPARATION AND STANDARDIZATION OF GLUTARALDEHYDE STOCK SOLUTION Dilute 1 mL 25% aqueous glutaraldehyde to 25 mL with distilled, deionized water. Place 10.0 mL 1.13 M sodium sulfite solution in a beaker and stir magnetically. With a pH meter, adjust pH to between 8.5 and 10 with base or acid. Record the pH. Add 1.0 mL glutaraldehyde stock solution. The pH should be about 12. Titrate the solution back to its original pH with 0.02N sulfuric acid. If the endpoint pH is overrun, back-titrate to the endpoint with 0.01N sodium hydroxide. Calculate the concentration, Cs (µg/µL) of the glutaraldehyde stock solution.

Cs

50.06

(Na

V a)

(Nb Vs

Vb)

.

where: 50.06 = equivalent weight of glutaraldehyde Na = normality of sulfuric acid Va = volume of sulfuric acid (mL) used for titration Nb = normality of sodium hydroxide Vb = volume of sodium hydroxide (mL) used for back titration Vs = volume of glutaraldehyde stock solution (1.0 mL).

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition