Rapid and Sensitive Spectrophotometric ... - AstonJournals
Rapid and Sensitive Spectrophotometric ... - AstonJournals Rapid and Sensitive Spectrophotometric ... - AstonJournals
Absorbance Chemical Sciences Journal, Vol. 2012: CSJ-80 7 O Br CH 3 OH O Br CH 3 O O Br CH 3 O H 3 C O Br H 3 C Br H 3 C Br + H + SO 2 SO 3 H SO 3 BCP (lactoid ring) (quinoid ring) deprotonated dye O Propranolol base (PPL) Br CH 3 N O O H OH O N H2 + H H + 3 C Br OH SO 3 + + O H 3 C Br CH 3 SO 3 O Br (c) 1:1 ion-pair complexes of PPL-BCP (measured at 420 nm) Scheme 1: (a) Tentative reaction mechanism for PPL-BTB ion-pair complex formation, (b) Tentative reaction mechanism for PPL-BCG ion-pair complex formation, (c) Tentative reaction mechanism for PPL-BCP ion-pair complex formation. 0.6 0.5 0.4 Sample BTB Blank BTB Sample BCG Blank BCG Sample BCP Blank BCP 0.3 0.2 0.1 0.0 360 380 400 420 440 460 480 500 520 540 560 Wavelength, nm Figure 2: Absorption spectra (4 µg ml -1 of PPL in both methods A and B, and 4.8 µg ml -1 of PPL in method C) http://astonjournals.com/csj
Absorbance Absorbance 8 Research Article 0.6 0.5 PPL-BTB ion pair complex PPL-BTB blank PPL-BCG ion pair complex PPL-BCG blank PPL-BCP ion pair complex PPL-BCP blank 0.4 0.3 0.2 0.1 0.0 1,4-Dioxan Chloroform Acetonitrile Acetone Dichloromethane Solvents Figure 3: Effect of solvents on the formation of PPL-BTB complex (3.2 µg ml -1 PPL), PPL- BCG complex (4.0 µg ml -1 PPL) and PPL-BCP complex (4.8 µg ml -1 PPL). 3.1.3 Effect of dye concentration and reaction time The effect of the dye-concentration on the intensity of the color developed at selected wavelengths was studied by measuring the absorbance of solutions containing a fixed concentration of PPL (2.4, 3.5 and 5.0 μg ml -1 in methods A, B and C, respectively) and different amounts (0.5 - 3.0 ml) of the respective dye of 0.1% BTB solution, 0.05% BCG solution and 0.1 % BCP solution. Maximum color intensity of the complex was achieved with 1 ml of dye solutions in all the methods and an excess dye slightly decreases the absorbance of the complex (Figure 4). The addition of the dye solution resulted in an immediate color development at room temperature for method A and B, and takes 5 min to develop color in method C. The formed ion-pairs were stable for at least 24 h in methods A and C and 90 min in method B. 0.45 0.40 0.35 0.30 BTB-PPL ion-pair complex Blank BCG-PPL ion-pair complex Blank BCP-PPL ion-pair complex Blank 0.25 0.20 0.15 0.10 0.05 0.00 0.5 1.0 1.5 2.0 2.5 3.0 Volume of reagent, ml Figure 4: Effect of reagent concentration on the formation PPL-BTB complex (2.4 µg ml -1 PPL), PPL-BCG complex (3.5 µg ml -1 PPL) and PPL-BCP complex (5.0 µg ml -1 PPL). http://astonjournals.com/csj
- Page 1 and 2: RESEARCH ARTICLE Rapid and Sensitiv
- Page 3 and 4: 2 Research Article Due to its thera
- Page 5 and 6: 4 Research Article 2.2 Materials Ph
- Page 7: 6 Research Article Br OH Br O Br O
- Page 11 and 12: 10 Research Article 3.2 Method vali
- Page 13 and 14: 12 Research Article 2.78 and 6.39,
- Page 15: 14 Research Article 16. Marques KL,
Absorbance<br />
Chemical Sciences Journal, Vol. 2012: CSJ-80<br />
7<br />
O<br />
Br<br />
CH 3<br />
OH<br />
O<br />
Br<br />
CH 3<br />
O<br />
O<br />
Br<br />
CH 3<br />
O<br />
H 3 C<br />
O<br />
Br<br />
H 3 C<br />
Br<br />
H 3 C<br />
Br<br />
+ H +<br />
SO 2<br />
SO 3 H<br />
SO 3<br />
BCP<br />
(lactoid ring)<br />
(quinoid ring)<br />
deprotonated dye<br />
O<br />
Propranolol base<br />
(PPL)<br />
Br<br />
CH 3<br />
N O<br />
O<br />
H<br />
OH O N<br />
H2<br />
+<br />
H H +<br />
3 C<br />
Br<br />
OH<br />
SO 3<br />
+<br />
+<br />
O<br />
H 3 C<br />
Br<br />
CH 3<br />
SO 3<br />
O<br />
Br<br />
(c)<br />
1:1 ion-pair complexes of<br />
PPL-BCP (measured at 420 nm)<br />
Scheme 1: (a) Tentative reaction mechanism for PPL-BTB ion-pair complex formation,<br />
(b) Tentative reaction mechanism for PPL-BCG ion-pair complex formation,<br />
(c) Tentative reaction mechanism for PPL-BCP ion-pair complex formation.<br />
0.6<br />
0.5<br />
0.4<br />
Sample BTB<br />
Blank BTB<br />
Sample BCG<br />
Blank BCG<br />
Sample BCP<br />
Blank BCP<br />
0.3<br />
0.2<br />
0.1<br />
0.0<br />
360 380 400 420 440 460 480 500 520 540 560<br />
Wavelength, nm<br />
Figure 2: Absorption spectra (4 µg ml -1 of PPL in both methods A <strong>and</strong> B, <strong>and</strong> 4.8 µg ml -1 of PPL in method C)<br />
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