ALDEHYDES, SCREENING: METHOD 2539, Issue 2, dated 15 August 1994 - Page 4 of 10 chrom atogram ). a. Analyze samples with GC retention times matching any oxazolidine by GC/MS using the same GC columns and conditions if possible. Alternate columns such as a DB-WAX (formaldehyde, acetaldehyde, propanal) or DB-1 (remaining aldehydes) may also be used for GC/MS confirmation depending on which aldehyde is suspected. b. Determine the presence of oxazolidines by monitoring for specific ions known to be present in the derivative spectra. See Table 2 for characteristic ion table and Appendix C for re fere nce ma ss s pec tra. R eten tion t ime s by GC /MS mu st als o m atch auth entic oxazolidine standards. NOTE 1:
12.
This method may also sample aldehydes other than those listed. The presence of these other aldehydes can be confirmed by examination of the mass spectral data and observation of peaks at m/e 126 and at the molecular ion minus one mass unit. The molecular ion for a particular aldehyde is equal to the molecular weight of the original aldehyde plus 97. Fragmentation patterns are also important for the identification of the oxazolidines. NOTE 2: The absence of some C 3-C 5 aldehydes, such as propionaldehyde, isobutyraldehyde and crotonaldehyde, does not necessarily mean that these compounds are not present in the air sampled. These compounds are not efficiently trapped by the sorbent, and will readily breakthrough the sampler sorbent beds. NOTE 3: Higher molecular weight aldehydes, such as isovaleraldehyde, hexanal and hep tanal, p roba bly will be mo re efficien tly collecte d on th e sorb ent ow ing to their low er va por pre ssu re. T hus , abs enc e of th ese com pou nds in sa mp le results may be indicative of the absence of these compounds in the environment sampled. Rep ort the p resen ce of a particu lar alde hyde if: a. There is a detectable peak by GC-FID at the correct retention time for that aldehyde derivative. b. The correct mass spectrum for the derivative is obtained by GC/MS at the proper retention time.
REFERENCES: [1] [2] [3] [4]
NIOSH Manual of Analytical Methods, 3rd ed., P.M. Eller, Ed., DHHS (NIOSH) Publication No. 84-100 (1984). Occupational Safety and Health Administration, "OSHA Analytical Method Manual," American Confere nce of G overnm ental Industrial Hygien ists, Cincinnati, OH (19 85). Kennedy, E. R., P. F. O'Connor, Y. T. Gagnon. Determination of Acrolein in Air as an Oxa zolidine Deriva tive by G as C hrom atogr aph y. A n al . C h em ., 56, 2120-21 23 (1984 ). Kennedy, E. R., Y. T. Gagnon, J. R. Okenfuss, A. W. Teass. The Determination in Air of Selected Low-molecular Weight Aldehydes as Their Oxazolidines by Capillary Gas Chro ma togra phy. Appl. Ind. Hyg., 3, 274-279 (1988).
METHOD WRITTEN (REVISED) BY: Ardith A. Grote and Eugene R. Kennedy, Ph.D., NIOSH/DPSE.
TABLE 1. GENERAL INFORMATION Compound Limits (ppm)
d(g/mL) VP(mm Hg) NIOSH Manual of Analytical Methods (NMAM), Fourth Edition
Exposure
