Table 1 Spectral characteristics of some cationic dyes and their IAs
with heteropoly anions
Organic dye
HPA
ε
Dye
ε
IA
in
excess
of dye;
λ
anal
, nm
Δλ
max
,
nm
ε
IA
/ε
Dye
ε
Dye
in
excess
of
HPA at
λ
anal
ε
Dye
at
λ
anal
ε
IA
/ε
Dye
at λ
anal
Astra Phloxine
[GaW
12
O
40
]
5-
142000;
542
205000;
578
38
1.44
38240
3360
61
Rhodamine 6G
92500;
525
102500;
568
43
1.11
16530
5170
20
Crystal Violet
105000;
590
77500;
646
56
0.74
13500
9250
8.4
Malachite
Green
61250;
620
62500;
668
48
1.02
13000
6500
9.6
Chrompyrazole-
1
56250;
600
27500;
650
50
0.49
13750
5000
5.5
Astra Phloxine
[SiW
12
O
40
]
4-
142000;
542
-
-
-
40000
4000
-
Rhodamine 6G
92500;
525
-
-
-
17500
6100
-
Crystal Violet
105000;
590
-
-
-
16250
9250
-
Malachite
Green
61250;
620
-
-
-
15000
7100
-
Chrompyrazole-
1
56250;
600
-
-
-
15500
5000
-
Astra Phloxine
[PW
12
O
40
]
3-
142000;
542
212500;
570
28
1.50
44500
3450
-
Rhodamine 6G
92500;
525
107500;
558
33
1.16
18700
6250
-
Crystal Violet
105000;
590
72500;
650
60
0.69
18750
9250
-
Malachite
Green
61250;
620
51250;
662
42
0.84
18250
7125
-
Chrompyrazole-
1
56250;
600
27500;
650
50
0.49
13750
5000
-
Astra Phloxine
[BiJ
4
-
]
142000;
542
60400;
610
68
0.43
Representatives of four classes of basic organic dyes, most often used in the
development of analytical methods, namely triphenylmethane, rhodamine,
polymethine and thiazine, were investigated. Spectra were obtained in the excess of the
dye and in the excess of HPA. In the latter case, with a sufficiently large excess of
HPA, the entire dye is converted to an aggregated form, which allowed to observe the
spectra of IAs without overlapping with the free dye spectrum. In a sufficiently large
excess of the dye, the whole HPA is bound into the IA.
- 1422 -