| Parameter |
Methods |
A |
B |
C |
D |
I |
II |
I |
II |
I |
II |
I |
II |
| pH |
3.0 |
3.0 |
2.2 |
2.2 |
- |
- |
- |
- |
| Solvent |
chloroform |
chloroform |
chloroform |
chloroform |
acetonitrile |
acetonitrile |
acetonitrile |
acetonitrile |
| λmax |
420 |
424 |
480 |
480 |
415 |
841 |
415 |
841 |
| Molar ratio (D:R) |
1 : 1 |
1 : 1 |
1 : 1 |
1 : 1 |
1:1 |
1:1 |
1:1 |
1:1 |
| pK |
4.64 |
5.45 |
4.14 |
4.77 |
3.78 |
3.58 |
3.90 |
3.73 |
| Beer’s law limits (µg mL−1) |
2.0 - 16 |
2.0 – 14 |
2.0 - 18 |
2.0 -14 |
1.4 – 20.6 |
1.4 – 24.0 |
1.6 -22.4 |
2.0 - 25.5 |
| Ringbom Range (µg Ml−1) |
3.6 – 14.4 |
3.8 - 12.2 |
3.7 - 16.4 |
3.8 - 12.2 |
3.0 – 19.2 |
3.0 – 22.5 |
3.0 – 21.5 |
3.4 – 23.5 |
| Molar absorptivity (L mol−1 cm−1) |
4.2 × 104 |
5.5 × 104 |
5.0 × 104 |
4.1 × 104 |
1.72 × 104 |
1.76 ×104 |
1.37 ×104 |
1.28 ×104 |
| Sandell’s sensitivity (ng cm−2) |
10.2 |
7.7 |
8.8 |
10.8 |
2.27 |
2.50 |
2.86 |
3.40 |
| Range of error % |
-0.67:0.34 |
-0.55:0.66 |
-0.66:0.54 |
-0.51:0.45 |
-0.35:0.55 |
-0.50:0.75 |
-0.45:0.75 |
-0.70:0.55 |
| Regression equation * |
|
|
|
|
|
|
|
|
| Intercept |
0.250 |
0.098 |
0.093 |
0.310 |
- 0.075 |
- 0.11 |
0.20 |
- 0.088 |
| Slope |
0.098 |
0.130 |
0.113 |
0.093 |
0.044 |
0.040 |
0.035 |
0.029 |
| Correlation coefficient (r) |
0.9991 |
0.9986> |
0.9989 |
0.9981 |
0.9992 |
0.9996 |
0.9998 |
0.9994 |
| t-value (2.56)* * |
1.29 |
1.56 |
1.13 |
1.37 |
1.06 |
1.34 |
0.96 |
1.23 |
| F- value (5.05)* * |
2.18 |
2.73 |
2.58 |
2.61 |
2.24 |
2.86 |
2.05 |
2.58 |
*A = a + bC, where C is the concentration in mg mL−1
** Values in parentheses are the theoretical values for t- and F- values at 95% confidence limits and five degrees of freedom. |
