Response Surface Optimization of a Rapid Ultrasound-Assisted Extraction Method for Simultaneous Determination of Tetracycline Antibiotics in Manure
Table 3
Analysis of variance of the response surface quadratic model.
Source
Sum of squares
Dfa
Mean square
-valueb
valuec Prob >
Model
418.10
9
46.46
49.74
0.0002
, pH
15.74
1
15.74
16.85
0.0093
, volume (mL)
135.3
1
135.3
144.86
<0.0001
, temperature (°C)
119.66
1
119.66
128.11
<0.0001
1.22
1
1.22
1.31
0.3047
6.84
1
6.84
7.32
0.0425
0.013
1
0.013
0.014
0.9099
17.34
1
17.34
18.57
0.0077
10.26
1
10.26
10.99
0.0211
101.49
1
101.49
108.67
0.0001
Residual
4.67
5
0.93
Lack of fit
3.84
3
1.28
3.09
0.2540
Pure error
0.83
2
0.41
0.9889
Adj
0.9691
Degree of freedom. bTest for comparing model variance with residual (error) variance. cProbability of seeing the observed -value if the null hypothesis is true.