Figure 6. UV spectral data for 4-ADNT product compared to glyoxal and pyruvic aldehyde

0.08

436.9 nm

Glyoxal

Wavelength (nm)

Figure 6. UV spectral data for 4-ADNT product compared to glyoxal

and pyruvic aldehyde.

5

3

4 - Glyoxylic

4 - Pyruvic

4

4 - Derivative

4 - Pyruvalde

2

3

Glyoxylic

Pyruvic

Glyoxal

Pyruvalde

2

1

0

40

80

120

160

200

40

80

120

160

200

0

Time (min)

a. 2-ADNT.

b. 4-ADNT.

Figure 7. Quantitative determination of 2,4-dinitrophenylhydrazone derivatives of products from 2-ADNT

and 4-ADNT.

confirmed the generation of pyruvic acid as a stable end-product. Based on chromatographic re-

tention times, glycolic acid (HOCH2COOH) and acetic acid were also identified. Other acids ap-

peared in the profile, but their retention times could not be matched with authentic standards.

Oxalic acid eluted near the dead volume and was masked by the large amounts of nitrate ion

generated during ozonation. A comparison of acids generated from 2-ADNT and 4-ADNT is

shown in Figure 8 and indicates the direct difference in product compositions for identical ozona-

tion times.

Using anion exchange with conductivity detection, nitrate ion could be resolved from oxalic

acid and other carboxylic acids. Formic, malonic, oxalic, and acetic acids were observed. The tenta-

tive identifications of acids observed by this technique are shown in Figure 9 for 2-ADNT and 4-

ADNT. The product profile was found not to agree with that observed on the Supelcogel column

(with UV detection), especially with respect to formic and pyruvic acids. These results indicate

that other methods of confirmatory analysis need to be addressed for the carboxylic acid fraction.

7