CHEMOMETRICS ASSISTED UV-SPECTROPHOTOMETRIC ...

Table 5. Actual and predicted amounts of salicylic acid given by applying first derivative
zero crossing points spectrophotometric techniques for pure, synthetic mixtures with
resorcinol and luna soap and dorin emulsion determined at 290.5 nm and 317.5 nm .
Component
analyzed
Pure salicylic acid
Salicylic acid in
binary mixture
Concentrat
ions used
(µg/ml)
µg/ml
Dorin emulsion 10(5) 7.41 130.2 12.8 13.30 266.1 5.1
Luna soap 10(10) 12.27 109.7 0.3 15.26 152.6 3.4
* ( ) the concentrations of resorcinol in the studied mixtures in µg/ml
∗ RSD is the relative standard deviation
Recovery at 290.5 nm Recovery at 317.5 nm
%
39
∗RSD
µg/ml
%
∗RSD
5 5.07 101.4 3.8 6.27 125.3 16
10 10.32 103.3 3.6 10.36 103.6 3.5
15 15.13 100.9 1.9 15.04 100.3 1.0
20 20.45 102.3 3.4 19.60 98.0 4.3
25 23.51 94.0 1.3 22.63 90.5 3.7
30 30.01 100.0 1.3 28.45 94.8 5.2
35 34.74 99.3 0.6 35.78 102.2 1.7
40 40.89 102.2 1.1 41.32 103.3 2.0
45 44.62 99.2 0.8 45.85 101.9 0.6
50 50.26 100.5 1.4 49.69 99.4 0.4
10( 5)* 12.21 118.3 0.1 11.51 115.1 6.9
10(10) 13.16 128.1 0.5 14.10 141.0 6.3
with resorcinol 5(10) 8.64 162.9 2.1 8.57 171.3 5.3