AN 360: Rapid Determination of Azo Dyes in Textiles Using ... - Dionex

Column: Acclaim 120 C18 3 µm,
120 Å (2.1 x 150 mm)
Eluent: H2O/5% CH3CN/4% CH3OH
H2O/40% CH3CN/45% CH3OH
Temperature: 30 °C
Peaks:
1. 2,4-Diaminotoluene
2. 4,4’-Oxydianiline
3. 2-Anisidine
4. 4,4’-Benzidine
5. 4-Methoxy-1,3-Phenylenediamine
6. o-Toluidine
7. Bis-4-aminophenylmethane
8. 2,4-Dimethylaniline
9. 2-Methoxy-5-methylaniline
10. 4-Cholroaniline
11. 2,6-Dimethylaniline
1 2 3
4
5 6 7 8
9
10
11
12 13
Flow Rate: 250 µL/min
Inj. Volume: 10 µL
Detection: UV, 278 nm
MSQ, APCI positive ionization
12. o-Dianisidine
13. o-Tolidine
14. 2-Methyl-5-nitroaniline
15. 4,4’-Methylenebis-(2-methylaniline)
16. 2-Aminonapthaline
17. 4,4’-Thiodianiline
18. 4-Chloro-2-methylaniline
19. 4-Aminoazobenzene
20. 3,3’-Dichlorobenzidine
21. 4-Aminobiphenyl
22. 4,4’-Methylenebis-(2-chloroaniline)
0 10 20 30 40 45
Minutes
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Figure 1. UV separation of azo dye standard mixture detected at
278 nm.
rEsults and dIscussIon
A tertiary gradient was used because acetonitrile was
found to improve the resolution of the peaks eluting at
the beginning of the analysis, while methanol improved
separation of the peaks at the end of the run. Ammonium
acetate was used to maintain a pH of 4, ensuring analytes
remained in the the acid form; this resulted in improved
detection by the mass spectrometer.
Using the photodiode array detector, two
wavelengths, 240 and 278nm, demonstrated optimum
response for azo dye detection. Figures 1 and 2 show the
detection and separation of the 22 aromatic amines, each
at a concentration of 5 mg/L.
14
16
15
17
18
19 20
21
22
Column: Acclaim 120 C18 3 µm,
120 Å (2.1 x 150 mm)
Eluent: H2O/5% CH3CN/4% MeOH
H2O/40% CH3CN/45% MeOH
Temperature: 30 °C
Peaks:
1. 2,4-Diaminotoluene
2. 4,4’-Oxydianiline
3. 2-Anisidine
4. 4,4’-Benzidine
5. 4-Methoxy-1,3-Phenylenediamine
6. o-Toluidine
7. Bis-4-aminophenylmethane
8. 2,4-Dimethylaniline
9. 2-Methoxy-5-methylaniline
10. 4-Cholroaniline
11. 2,6-Dimethylaniline
12. o-Dianisidine
13. o-Tolidine
14. 2-Methyl-5-nitroaniline
3
3
1 2 5 6
16
7 10
17
11
14
8 15 18
9
Flow Rate: 250 µL/min
Inj. Volume: 10 µL
Detection: UV: 240 nm, 278 nm
MSQ, APCI positive ionization
15. 4,4’-Methylenebis-(2-methylaniline)
16. 2-Aminonapthaline
17. 4,4’-Thiodianiline
18. 4-Chloro-2-methylaniline
19. 4-Aminoazobenzene
20. 3,3’-Dichlorobenzidine
21. 4-Aminobiphenyl
22. 4,4’-Methylenebis-(2-chloroaniline)
Figure 2. Comparison of azo dye standards detected by UV and
mass spectrometric detection. The UV trace appears at the bottom
and is expanded to show the detection of all compounds using
SIM (selected ion monitoring) channels in the mass spectrometer.
4 Rapid Determination of Azo Dyes in Textiles Using Dionex ASE and UltiMate 3000 HPLC Systems
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12 13
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15
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10 22
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20
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