CHEMOMETRICS ASSISTED UV-SPECTROPHOTOMETRIC ...

Table 14. Actual and predicted amounts of salicylic acid (SA) and resorcinol (RE) given by
applying CLS spectrophotometric techniques for pure, synthetic mixtures, Dorin emulsion,
and Luna soap. (250 nm-400 nm)
Component
analyzed
Pure
component
SA Conc.
Found RE conc. Recovery
used (µg/ml)
Conc.used
µg/ml (%) ∗ RSD µg/ml µg/ml (%) ∗
RSD
5 5.25 106.8 5.0 5 5.28 105.7 2.0
10 9.78 100.2 5.1 10 10.28 102.8 1.9
15 14.85 99.8 0.9 15 15.27 101.8 0.2
20 20.41 103.1 3.9 20 20.54 102.7 0.4
25 23.67 97.1 2.2 25 25.11 100.4 0.3
30 30.71 101.8 1.0 30 30.15 100.5 1.6
35 35.03 99.5 0.4 35 35.06 100.2 0.8
40 40.66 101.2 1.1 40 40.15 100.4 1.5
45 45.49 100.9 0.9 45 44.90 99.7 0.8
50 49.15 98.2 0.7 50 49.42 98.8 0.1
Synthetic
mixtures
Dorin
10(5)
10(10)
5(10)
10.23
10.45
5.17
99.7
101.5
100.8
3.3
1.0
0.6
5(10)
10(10)
10(5)
4.98
10.14
10.19
99.5
101.4
101.9
3.2
2.1
1.6
emulsion 10(5) 10.25 102.5 2.0 5(10) 4.98 99.6 0.6
Luna soap 10(10) 10.45 104.5 1.8 10(10) 10.14 101.4 0.4
∗ RSD is the relative standard deviation
As a preliminary conclusion;
-although the CLS method is a sufficiently good method for analysis of individual
compounds, the method is failed to determine the proper concentrations of components of
benzoic acid in the laboratory preparations and commercial formulations analyzed. Thus the
method is failed to determine the binary combination of benzoic acid and salicylic acid.
- the CLS method is a sufficiently good method for analysis of individual compounds
(salicylic acid and resorcinol ) and their binary mixtures with a considerably good precision
when applied in the same ranges of calibration domains. The variations and relative
deviations from the mean observed is insignificant. Thus, CLS method is a suitable method
for simultaneous determination of salicylic acid and resorcinol mixture.
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