A quantitative structure-retention relationships (QSRRs) method is employed to predict the retention time of 300 pesticide residues in animal tissues separated by gas chromatography-mass spectroscopy (GC-MS). Firstly, a six-parameter QSRR model was developed by means of multiple linear regression. The six molecular descriptors that were considered to account for the effect of molecular structure on the retention time are number of nitrogen, Solvation connectivity index-chi 1, Balaban
Pesticides are used on a large scale for agricultural purposes. The adverse effects of pesticides on both human health and the environment are a matter of public concern. Thus, both the actual state and the transition of pesticide residues in various matrices including water, soil, and agricultural products should be extensively monitored. These researches should be undertaken using an efficient analytical system with a laborsaving and cost-effective device, as pesticides as well as applicable fields of research rang over a broad spectrum. Conventional sample preparation methods used to analyze pesticide residues in various matrices require expensive instrumentation, an expert analyst [
QSRR studies [
Today artificial neural networks [
Development of the multiple linear regression and artificial neural networks in the present work relies on a data set taken from reference [
Experimental, ANN, and MLR predicted values of the retention times (
Number | Pesticide | ( | |||
---|---|---|---|---|---|
Training set | |||||
1 | Allidochlor | 8.78 | 10.22 | 9.83 | −1.05 |
2 | Dichlormid | 9.74 | 10.27 | 9.88 | −0.14 |
3 | Etridiazol | 10.42 | 16.11 | 12.9 | −2.48 |
4 | Chlormephos | 10.53 | 11.88 | 14 | −3.47 |
5 | Propham | 11.36 | 14.17 | 12.13 | −0.77 |
6 | Cycloate | 13.56 | 16.32 | 16.4 | −2.84 |
7 | Diphenylamine | 14.55 | 18.13 | 15.58 | −1.03 |
8 | Chlordimeform | 14.93 | 17.44 | 13.69 | 1.24 |
9 | Ethalfluralin | 15.00 | 16.17 | 14.56 | 0.9 |
10 | Thiometon | 16.20 | 18.1 | 17.82 | −1.62 |
11 | Atrazine-desethyl | 16.76 | 13.96 | 17.25 | −0.49 |
12 | Clomazone | 17.00 | 20.95 | 18.63 | −1.63 |
13 | Fonofos | 17.31 | 20.48 | 16.24 | 1.07 |
14 | Simazine | 17.85 | 16.99 | 18.93 | −1.08 |
15 | Propetamphos | 17.97 | 19.72 | 18.93 | −0.96 |
16 | Secbumeton | 18.36 | 20.2 | 19.21 | −0.85 |
17 | Dichlofenthion | 18.80 | 21.02 | 17.38 | 1.42 |
18 | Pronamide | 18.72 | 19.61 | 21.15 | −2.43 |
19 | Mexacarbate | 18.83 | 17.05 | 18.64 | 0.2 |
20 | Aldrin | 19.67 | 22.92 | 21.33 | −1.66 |
21 | Dinitramine | 19.35 | 18.57 | 16.45 | 2.9 |
22 | Ronnel | 19.80 | 22.63 | 21.2 | −1.4 |
23 | Cyprazine | 20.18 | 19.82 | 18.43 | 1.75 |
24 | Beta-HCH | 20.31 | 16.11 | 16.93 | 3.38 |
25 | Metalaxyl | 20.67 | 20.19 | 21.92 | −1.25 |
26 | Chlorpyrifos (-ethyl) | 20.96 | 25.26 | 22.59 | −1.63 |
27 | Methyl-parathion | 20.82 | 22.85 | 21.44 | −0.62 |
28 | Malathion | 21.54 | 21.2 | 22.9 | −1.36 |
29 | Fenitrothion | 21.62 | 23.17 | 21.19 | 0.43 |
30 | Paraoxon-ethyl | 21.57 | 22.19 | 21.39 | 0.18 |
31 | Triadimefon | 22.22 | 25.41 | 25.62 | −3.4 |
32 | Parathion | 22.32 | 24 | 23.28 | −0.96 |
33 | Pendimethalin | 22.59 | 20.84 | 19.77 | 2.82 |
34 | Linuron | 22.44 | 21.13 | 19.94 | 2.5 |
35 | Bromophos-ethyl | 23.06 | 23.18 | 21.51 | 1.55 |
36 | trans-chlordane | 23.29 | 23.4 | 22.61 | 0.68 |
37 | Phenthoate | 23.30 | 24.91 | 25.59 | −2.29 |
38 | Fenothiocarb | 23.79 | 23.76 | 24.85 | −1.06 |
39 | Prothiophos | 24.04 | 24.99 | 23.69 | 0.35 |
40 | Dieldrin | 24.43 | 24.77 | 24.55 | −0.12 |
41 | Procymidone | 24.36 | 22.91 | 26.47 | −2.11 |
42 | Methidathion | 24.49 | 27.18 | 26.96 | −2.47 |
43 | Napropamide | 24.84 | 24.35 | 23.12 | 1.72 |
44 | Fenamiphos | 25.29 | 23.4 | 26.85 | −1.56 |
45 | Aramite | 25.60 | 26.63 | 25.36 | 0.24 |
46 | Bupirimate | 26.00 | 25.11 | 24.63 | 1.37 |
47 | Carboxin | 26.25 | 23.23 | 25.54 | 0.71 |
48 | Flutolanil | 26.23 | 22.66 | 27.39 | −1.16 |
49 | Ethion | 26.69 | 26.7 | 26.6 | 0.09 |
50 | Sulprofos | 26.87 | 25.6 | 25.14 | 1.73 |
51 | Etaconazole-2 | 26.89 | 22.06 | 26.1 | 0.79 |
52 | Myclobutanil | 27.19 | 26.34 | 26.45 | 0.74 |
53 | Diclofop-methyl | 28.08 | 28.79 | 27.35 | 0.73 |
54 | Propiconazole | 28.15 | 30.15 | 28.96 | −0.81 |
55 | Fensulfothin | 27.94 | 25.84 | 26.94 | 1 |
56 | Bifenthrin | 28.57 | 27.56 | 29.69 | −1.12 |
57 | Mirex | 28.72 | 28.48 | 28.33 | 0.39 |
58 | Benodanil | 29.14 | 22.77 | 27.08 | 2.06 |
59 | Nuarimol | 28.90 | 26.9 | 26.93 | 1.97 |
60 | Oxadexyl | 29.59 | 23.49 | 25.44 | 4.06 |
61 | Tetramethirn | 29.59 | 28.2 | 28.88 | 0.71 |
62 | Phosmet | 30.46 | 29.34 | 29.94 | 0.52 |
63 | Oxycarboxin | 31.00 | 25.76 | 28.63 | 2.37 |
64 | cis-Permethrin | 31.42 | 31.5 | 32.3 | −0.9 |
65 | trans-Permethrin | 31.68 | 32.74 | 32.6 | −0.92 |
66 | Pyrazophos | 31.60 | 32.87 | 29.97 | 1.63 |
67 | Cypermethrin | 33.19 | 33.64 | 33.73 | −0.54 |
68 | Fenvalerate | 34.45 | 35.59 | 34.07 | 0.38 |
69 | Deltamethrin | 35.77 | 32.69 | 33.93 | 1.84 |
70 | EPTC | 8.54 | 9.64 | 11.15 | −2.61 |
71 | Butylate | 9.49 | 10.01 | 10.12 | −0.63 |
72 | Dichlobenil | 9.75 | 11.27 | 11.75 | −2 |
73 | Pebulate | 10.18 | 11.32 | 11.54 | −1.36 |
74 | Nitrapyrin | 10.89 | 10.95 | 12.12 | −1.23 |
75 | Chloroneb | 11.85 | 15.37 | 13.01 | −1.16 |
76 | Tecnazene | 13.54 | 15.8 | 16.61 | −3.07 |
77 | Heptenophos | 13.78 | 18.84 | 15.01 | −1.23 |
78 | Hexachlorobenzene | 14.69 | 16.1 | 18.31 | −3.62 |
79 | Ethoprophos | 14.40 | 13.64 | 12.5 | 1.9 |
80 | cis-Diallate | 14.75 | 14.67 | 15.7 | −0.95 |
81 | Propachlor | 14.73 | 16.12 | 13.97 | 0.76 |
82 | Trifluralin | 15.23 | 19.7 | 14.95 | 0.28 |
83 | Chlorpropham | 15.49 | 16.41 | 16.17 | −0.68 |
84 | Sulfallate | 15.75 | 12.79 | 12.78 | 2.97 |
85 | Alpha-HCH | 16.06 | 15.99 | 18.04 | −1.98 |
86 | Terbufos | 16.83 | 16.38 | 17.13 | −0.3 |
87 | 4,4-DDE | 23.92 | 24.19 | 24.68 | −0.76 |
88 | Chlorbufam | 17.85 | 18.15 | 18.66 | −0.81 |
89 | Fluotrimazole | 28.39 | 26.67 | 28.64 | −0.25 |
90 | Terbuthylazine | 18.07 | 18.42 | 19.7 | −1.63 |
91 | Monolinuron | 18.15 | 19.36 | 20.27 | −2.12 |
92 | Cyanophos | 18.73 | 20.34 | 19.53 | −0.8 |
93 | Chlorpyrifos-methyl | 19.38 | 23.86 | 21.45 | −2.07 |
94 | Desmetryn | 19.64 | 17.4 | 18.43 | 1.21 |
95 | Alachlor | 20.03 | 19.24 | 19.27 | 0.76 |
96 | Terbutryn | 20.61 | 20.03 | 19.37 | 1.24 |
97 | Thiobencarb | 20.63 | 20.77 | 19.73 | 0.9 |
98 | Dicofol | 21.33 | 23.76 | 23.45 | −2.12 |
99 | Metolachlor | 21.34 | 21.05 | 21.68 | −0.34 |
100 | Methoprene | 21.71 | 23.08 | 22.07 | −0.36 |
101 | Bromofos | 21.75 | 23.72 | 22.31 | −0.56 |
102 | Ethofumesate | 21.84 | 24.27 | 23.8 | −1.96 |
103 | Isopropalin | 22.10 | 26.6 | 24.73 | −2.63 |
104 | Propanil | 22.68 | 16.94 | 19.79 | 2.89 |
105 | Crufomate | 22.93 | 21.31 | 19.59 | 3.34 |
106 | Chlorfenvinphos | 23.19 | 23.53 | 23.32 | −0.13 |
107 | cis-Chlordane | 23.55 | 23.4 | 21.71 | 1.84 |
108 | Tolylfluanide | 23.45 | 22.76 | 23.52 | −0.07 |
109 | Butachlor | 23.82 | 22.55 | 24.27 | −0.45 |
110 | Chlozolinate | 23.83 | 25.54 | 23.06 | 0.77 |
111 | Crotoxyphos | 23.94 | 24.26 | 24.8 | −0.86 |
112 | Iodofenphos | 24.33 | 23.85 | 21.87 | 2.46 |
113 | Chlorbromuron | 24.37 | 21.89 | 20.71 | 3.66 |
114 | Profenofos | 24.65 | 22.73 | 23.34 | 1.31 |
115 | Buprofezin | 24.87 | 24.53 | 23.88 | 0.99 |
116 | 2,4′-DDD | 24.94 | 23.16 | 23.56 | 1.38 |
117 | Endrin | 25.15 | 24.92 | 25.1 | 0.05 |
118 | Hexaconazole | 24.92 | 26.84 | 26.97 | −2.05 |
119 | 2,4-DDT | 25.56 | 22.31 | 23.68 | 1.88 |
120 | Methoprotryne | 25.63 | 26.87 | 25.6 | 0.03 |
121 | Erbon | 25.68 | 25.93 | 26.83 | −1.15 |
122 | Chloropropylate | 25.85 | 25.43 | 25.32 | 0.53 |
123 | Nitrofen | 26.12 | 23.08 | 28.85 | −2.73 |
124 | Oxyfluorfen | 26.13 | 25.59 | 29.37 | −3.24 |
125 | Chlorthiophos | 26.52 | 26.26 | 25.96 | 0.56 |
126 | Endosulfan I | 26.72 | 23.96 | 26.39 | 0.33 |
127 | 4,4-DDT | 27.22 | 22.9 | 25.15 | 2.07 |
128 | Carbofenothion | 27.19 | 27 | 26.87 | 0.32 |
129 | Benalyxyl | 27.54 | 27.7 | 27.98 | −0.44 |
130 | Edifenphos | 27.94 | 25.87 | 25.96 | 1.98 |
131 | Triazophos | 28.23 | 27.84 | 26.84 | 1.39 |
132 | Chlorbenside sulfone | 28.88 | 26.15 | 27.85 | 1.03 |
133 | Endosulfan-sulfate | 29.05 | 28.31 | 28.93 | 0.12 |
134 | Bromopropylate | 29.30 | 25.93 | 27.74 | 1.56 |
135 | Benzoylprop-ethyl | 29.40 | 28.81 | 28.84 | 0.56 |
136 | Fenpropathrin | 29.56 | 28.79 | 29.79 | −0.23 |
137 | Phosalone | 31.22 | 31.11 | 31.56 | −0.34 |
138 | Azinphos-methyl | 31.41 | 31.36 | 30.37 | 1.04 |
139 | Fenarimol | 31.65 | 29.56 | 28.81 | 2.84 |
140 | Azinphos-ethyl | 32.01 | 32.91 | 31.79 | 0.22 |
141 | Prochloraz | 33.07 | 33.03 | 31.52 | 1.55 |
142 | Coumaphos | 33.22 | 28.77 | 30.86 | 2.36 |
143 | Cyfluthrin | 32.94 | 34.18 | 33.61 | −0.67 |
144 | Dichlorvos | 7.80 | 9.72 | 7.98 | −0.18 |
145 | Biphenyl | 9.00 | 16.62 | 11.96 | −2.96 |
146 | Vernolate | 9.82 | 11.57 | 10.9 | −1.08 |
147 | 3,5-Dichloroaniline | 11.20 | 10.42 | 10.55 | 0.65 |
148 | Molinate | 11.92 | 14.07 | 13.92 | −2 |
149 | Methacrifos | 11.86 | 15.7 | 13.49 | −1.63 |
150 | 2-Phenylphenol | 12.47 | 16.32 | 12.14 | 0.33 |
151 | cis-1,2,3,6-tetrahydrophthalimide | 13.39 | 12.35 | 11.96 | 1.43 |
152 | Fenobucarb | 14.60 | 14.42 | 13.7 | 0.9 |
153 | Prometon | 16.66 | 18.42 | 16.82 | −0.16 |
154 | Triallate | 17.12 | 15.55 | 13.9 | 3.22 |
155 | Pyrimethanil | 17.28 | 18.45 | 18.46 | −1.18 |
156 | Gamma-HCH | 17.48 | 16.12 | 18.09 | −0.61 |
157 | Disulfoton | 17.61 | 16.97 | 16.66 | 0.95 |
158 | Heptachlor | 18.49 | 21.61 | 19.83 | −1.34 |
159 | Isazofos | 18.54 | 22.62 | 20.07 | −1.53 |
160 | Fenpropimorph | 19.22 | 25 | 21.3 | −2.08 |
161 | Transfluthrin | 19.04 | 23.96 | 22.15 | −3.11 |
162 | Tolclofos-methyl | 19.69 | 21.11 | 18.51 | 1.18 |
163 | Metobromuron | 20.07 | 19.92 | 20.38 | −0.31 |
164 | HCH, epsilon- | 20.78 | 16.05 | 17.54 | 3.24 |
165 | Dipropetryn | 20.82 | 20.32 | 21.8 | −0.98 |
166 | Formothion | 21.42 | 17.67 | 18.96 | 2.46 |
167 | Diethofencarb | 21.43 | 20.66 | 19.42 | 2.01 |
168 | Dimepiperate | 22.28 | 21.74 | 21.92 | 0.36 |
169 | Bioallethrin-1 | 22.29 | 22.9 | 21.57 | 0.72 |
170 | 2,4-DDE | 22.64 | 22.46 | 24.45 | −1.81 |
171 | Fenson | 22.54 | 23.65 | 21.87 | 0.67 |
172 | Chlorthion | 22.86 | 24.7 | 22.65 | 0.21 |
173 | Prallethrin | 23.11 | 23.96 | 22.59 | 0.52 |
174 | Mecarbam | 23.46 | 22 | 25.24 | −1.78 |
175 | Flumetralin | 24.10 | 27.85 | 24.44 | −0.34 |
176 | Triadimenol | 24.22 | 25.2 | 24.81 | −0.59 |
177 | Pretilachlor | 24.67 | 22.65 | 24.59 | 0.08 |
178 | Uniconazole | 26.15 | 25.53 | 26 | 0.15 |
179 | Flusilazole | 26.19 | 29.21 | 27.8 | −1.61 |
180 | Fluorodifen | 26.59 | 25.19 | 25.07 | 1.52 |
181 | Diniconazole | 27.03 | 26.95 | 27.24 | −0.21 |
182 | Piperonyl butoxide | 27.46 | 28.93 | 26.8 | 0.66 |
183 | Mepronil | 27.91 | 25.31 | 27.43 | 0.48 |
184 | Fenazaquin | 28.97 | 29.38 | 30.6 | −1.63 |
185 | Fenoxycarb | 29.57 | 29.01 | 30.52 | −0.95 |
186 | Sethoxydim | 29.63 | 24.8 | 27.28 | 2.35 |
187 | Anilofos | 30.68 | 29.82 | 28.59 | 2.09 |
188 | Permethrin | 31.57 | 30.27 | 32.38 | −0.81 |
189 | Pyridaben | 31.86 | 31.57 | 30.56 | 1.3 |
190 | Fluoroglycofen-ethyl | 32.01 | 34.85 | 33.64 | −1.63 |
191 | Bitertanol | 32.25 | 32.05 | 30.82 | 1.43 |
192 | Etofenprox | 32.75 | 32.57 | 32.87 | −0.12 |
193 | Cycloxydim | 33.05 | 28.55 | 30.36 | 2.69 |
194 | Alpha-cypermethrin | 33.35 | 28.9 | 31.06 | 2.29 |
195 | Esfenvalerate | 34.65 | 36.73 | 34 | 0.65 |
196 | Difenconazole | 35.40 | 36.14 | 33.03 | 2.37 |
197 | Flumioxazin | 35.50 | 32.67 | 32.45 | 3.05 |
198 | Dimefox | 5.62 | −0.46 | 7.13 | −1.51 |
199 | Tri-iso-butyl phosphate | 11.65 | 10.47 | 12.32 | −0.67 |
200 | Crimidine | 13.13 | 12.37 | 12.09 | 1.04 |
201 | Chlorfenprop-methyl | 13.57 | 17.75 | 13.6 | −0.03 |
202 | 2,3,5,6-Tetrachloroaniline | 14.22 | 13.5 | 12.71 | 1.51 |
203 | Tri-n-butyl phosphate | 14.33 | 16.15 | 14.42 | −0.09 |
204 | 2,3,4,5-Tetrachloroanisole | 14.66 | 15.91 | 14.51 | 0.15 |
205 | Tebutam | 15.30 | 16.51 | 17.61 | −2.31 |
206 | Dioxabenzofos | 16.14 | 17.74 | 15.19 | 0.95 |
207 | Simetone | 16.69 | 17.79 | 16.84 | −0.15 |
208 | Atratone | 16.70 | 18.87 | 18.68 | −1.98 |
209 | Bromocylen | 17.43 | 18.53 | 17.24 | 0.19 |
210 | Cycluron | 17.95 | 17.22 | 19.68 | −1.73 |
211 | Musk ambrette | 18.62 | 18.86 | 17.77 | −1.15 |
212 | Musk xylene | 18.66 | 20.74 | 18.81 | −0.15 |
213 | Pentachloroaniline | 18.91 | 15.38 | 16.2 | 2.71 |
214 | Aziprotryne | 19.11 | 21.05 | 19.07 | 0.04 |
215 | Sebutylazine | 19.26 | 19.07 | 19.03 | 0.23 |
216 | Isocarbamid | 19.24 | 16.72 | 17.15 | 2.09 |
217 | Musk moskene | 19.46 | 21.79 | 21.16 | −1.7 |
218 | Dimethenamid | 19.55 | 20.54 | 20.39 | −0.84 |
219 | Fenchlorphos oxon | 19.72 | 21.04 | 18.44 | 1.28 |
220 | BDMC-2 | 19.74 | 15.49 | 19.3 | 0.44 |
221 | Paraoxon-methyl | 19.83 | 20.87 | 20.76 | −0.93 |
222 | Monalide | 20.02 | 19.22 | 21.33 | −1.31 |
223 | Isobenzan | 20.55 | 22.18 | 21.66 | −1.11 |
224 | Pyrimitate | 20.59 | 22.79 | 18.97 | 1.62 |
225 | Isodrin | 21.01 | 21.88 | 22.55 | −1.54 |
226 | Isomethiozin | 21.06 | 22.14 | 19.89 | 1.17 |
227 | Dacthal | 21.25 | 22.38 | 21.38 | −0.13 |
228 | 4,4-Dichlorobenzophenone | 21.29 | 21.45 | 19.45 | 1.84 |
229 | Nitrothal-isopropyl | 21.69 | 21.85 | 21.6 | 0.09 |
230 | Rabenzazole | 21.73 | 21.17 | 24.36 | −2.63 |
231 | Fuberidazole | 22.10 | 20.67 | 21.26 | 0.84 |
232 | Isofenphos oxon | 22.04 | 23.32 | 21.78 | 0.26 |
233 | Dicapthon | 22.44 | 22.74 | 22.2 | 0.24 |
234 | Isocarbophos | 22.87 | 24.01 | 22.75 | 0.12 |
235 | Phorate sulfone | 23.15 | 19.74 | 25.53 | −2.38 |
236 | Chlorfenethol | 23.29 | 21.98 | 22.52 | 0.77 |
237 | trans-Nonachlor | 23.62 | 25.1 | 24.51 | −0.89 |
238 | Dinobuton | 23.88 | 22.71 | 22.01 | 1.87 |
239 | DEF | 24.08 | 21.24 | 23.61 | 0.47 |
240 | Flurochloridone | 24.31 | 18.15 | 21.83 | 2.48 |
241 | Bromfenvinfos | 24.62 | 25.03 | 24.94 | −0.32 |
242 | Ditalimfos | 24.82 | 25.28 | 25.31 | −0.49 |
243 | 4,4-Dibromobenzophenone | 25.30 | 23.06 | 24.62 | 0.68 |
244 | Disulfoton sulfone | 26.16 | 20.66 | 24.24 | 1.92 |
245 | Cyproconazole | 27.23 | 26.87 | 26.41 | 0.82 |
246 | Phthalic acid, benzyl butyl ester | 27.56 | 27.11 | 26.22 | 1.34 |
247 | Clodinafop-propargyl | 27.74 | 31.2 | 29.61 | −1.87 |
248 | Fenthion sulfone | 28.55 | 27.46 | 29.4 | −0.85 |
249 | Metamitron | 28.63 | 21.78 | 27.39 | 1.24 |
250 | Tebufenpyrad | 29.06 | 30.01 | 29.27 | −0.21 |
251 | Cloquintocet-mexyl | 29.32 | 29.62 | 29.85 | −0.53 |
252 | Lenacil | 29.70 | 21.63 | 28.28 | 1.42 |
253 | Bromuconazole | 29.90 | 28.32 | 29.66 | 0.24 |
254 | Fenamiphos sulfone | 31.34 | 29.08 | 30.17 | 1.17 |
255 | Fluquinconazole | 32.62 | 32.22 | 30.22 | 2.4 |
256 | Fenbuconazole | 34.02 | 33.6 | 31.53 | 2.49 |
Test set | |||||
257 | Tetradifon | 30.70 | 29.14 | 30.26 | 0.44 |
258 | Fluorochloridone | 25.14 | 19.72 | 24.4 | 0.74 |
259 | Cyanofenphos | 28.43 | 27.78 | 29.74 | −1.31 |
260 | EPN | 30.06 | 30.42 | 31.71 | −1.65 |
261 | Benfluralin | 15.23 | 16.21 | 14.16 | 1.07 |
262 | Atrizine | 17.64 | 16.45 | 19.4 | −1.76 |
263 | Simetryn | 20.18 | 18.85 | 19.71 | 0.47 |
264 | Metribuzin | 20.33 | 17.61 | 17.78 | 2.55 |
265 | Bioallethrin-2 | 22.34 | 23.58 | 21.89 | 0.45 |
266 | Kresoxim-methyl | 25.04 | 27.47 | 27.78 | −2.57 |
267 | Propargite | 27.87 | 26.85 | 30.06 | −2.19 |
268 | Amitraz | 30.29 | 28.83 | 29.76 | 0.53 |
269 | Trietazine | 17.53 | 18.78 | 19.76 | −2.23 |
270 | Prosulfocarb | 19.51 | 21.08 | 21.51 | −2 |
271 | Octachlorostyrene | 20.60 | 20.81 | 23.38 | −2.78 |
272 | Methfuroxam | 22.45 | 21.15 | 24.43 | −1.98 |
273 | Flutriafol | 25.31 | 26.82 | 27.15 | −1.84 |
274 | Diclobutrazole | 25.95 | 27.22 | 27.61 | −1.66 |
275 | Triphenyl phosphate | 28.65 | 26.88 | 30.41 | −1.76 |
276 | Desbrom-leptophos | 30.15 | 27.97 | 28.32 | 1.83 |
277 | Propisochlor | 19.89 | 16.96 | 19.98 | −0.09 |
278 | Ametryn | 20.11 | 18.98 | 19.4 | 0.71 |
Valid set | |||||
279 | Quintozene | 16.75 | 18.1 | 18.4 | −1.65 |
280 | Prometryne | 20.13 | 19.82 | 19.71 | 0.42 |
281 | Chlorbenside | 22.96 | 23.73 | 25.4 | −2.44 |
282 | Oxadiazone | 25.06 | 26.67 | 26.72 | −1.66 |
283 | Tetrasul | 25.85 | 25.48 | 26.27 | −0.42 |
284 | Etaconazole-1 | 26.81 | 28.41 | 27.98 | −1.17 |
285 | Pyridaphenthion | 30.17 | 29.14 | 29.64 | 0.53 |
286 | trans-Diallate | 15.29 | 14.82 | 15.52 | −0.23 |
287 | Propazine | 17.67 | 18.15 | 19.5 | −1.83 |
288 | Pirimiphos-methyl | 20.30 | 23.66 | 22.81 | −2.51 |
289 | Dichlofluanid | 21.68 | 22.03 | 22.53 | −0.85 |
290 | Profluralin | 17.36 | 22.64 | 17.16 | 0.2 |
291 | Tetrachlorvinphos | 24.36 | 22.75 | 24.14 | 0.22 |
292 | Chlorfenson | 25.05 | 26.07 | 23.34 | 1.71 |
293 | 2,4-DDD | 24.94 | 26.13 | 27.65 | −1.75 |
294 | Leptophos | 30.19 | 30.5 | 29.65 | 0.54 |
295 | Nitralin | 30.92 | 29.65 | 29.37 | 1.55 |
296 | Fenamiphos sulfoxide | 31.03 | 26.93 | 30.38 | 0.65 |
297 | Dicloran | 17.89 | 26.94 | 17.14 | 0.75 |
298 | Perthane | 24.81 | 15.1 | 26.01 | −1.2 |
299 | Cyprodinil | 21.94 | 22.19 | 22.63 | −0.69 |
300 | Mefenacet | 31.29 | 29.75 | 30.27 | 1.02 |
All structures were generated with the HyperChem (Version 7) [
The main goal of the generation of the MLR model was to choose a set of suitable descriptors that can be used as inputs for construction of the ANN model. Linear models were formed by a stepwise selection of important descriptors and MLR model construction [
Specifications of the selected multiple linear regression model.
Descriptor | Notation | Coefficient | Mean effect |
---|---|---|---|
Number of nitrogen atoms | 0.980 (±0.123) | 0.091 | |
Solvation connectivity index-Chi1 | 2.191 (±0.125) | 1.467 | |
Balaban | −4.639 (±0.401) | −0.421 | |
Moran autocorrelation-lag 2/weighted by atomic sanderson electronegativity | MATS2e | −7.386 (±1.022) | −0.104 |
Total absolute charge (electronic charge index—ECI) | Qtot | 0.499 (±0.084) | 0.211 |
Radial Distribution-6.0/unweighted | RDF060u | −0.156 (±0.025) | −0.140 |
Constant | 7.045 (±1.346) |
A detailed description of theory behind artificial neural networks has been adequately described in several publications [
The best MLR model (Table
The correlation between these descriptors is shown in Table
Correlation matrix for descriptors applying in this work.
MATS2e | Qtot | RDF060u | ||||
---|---|---|---|---|---|---|
1 | ||||||
−0.162 | 1 | |||||
−0.120 | 0.540 | 1 | ||||
MATS2e | 0.315 | −0.240 | 0.065 | 1 | ||
Qtot | −0.082 | 0.427 | 0.034 | −0.535 | 1 | |
RDF060u | 0.084 | 0.634 | −0.363 | 0.162 | 0.433 | 1 |
The first descriptor with the larger mean effect is solvation connectivity index—chi 1 (
The positive sign for the mean effect of this descriptor reveals that molecules have higher numerical value of
Comparison of
Comparison of
The total absolute charge is the other descriptor which, also known as the electronic charge index (ECI), is the sum of absolute charge over all atoms in a molecule and is a measure of molecule polarity [
Comparison of Qtot values for pirimiphos-methyl and dichlobenil.
So the Moran autocorrelation-lag 2/weighted by atomic sanderson electronegativity can be a factor of electronegativity of moleculs. The last descriptor is radial distribution-6.0/unweighted. The 3D coordinates of the atoms of molecules can be transformed into a structure code that has a fixed number of descriptors irrespective of the size of a molecule. This task is performed by a structure coding technique referred to as radial distribution function code (RDF code) [
Formally, the radial distribution function of an ensemble of
The atomic properties
From the above discussion, it can be seen that all descriptors involved in the QSRR model has physical meaning, and these descriptors can account for the structural features that affect the retention time of under studied pesticides.
A graphical comparison of ANN and MLR analysis is given in Figure
Statistical parameters obtained using the ANN and MLR models.
Model | SEv | ||||||||
---|---|---|---|---|---|---|---|---|---|
ANN | 1.559 | 1.517 | 1.249 | 0.969 | 0.951 | 0.971 | 3928 | 188 | 334 |
MLR | 2.402 | 1.858 | 2.036 | 0.925 | 0.924 | 0.922 | 1508 | 118 | 113 |
Plot of the calculated
Plot of the residuals versus the experimental values of
Few structure-activity relationships involving pesticides have been published. In this study, we use MLR and ANN to predict the retention time of 300 pesticides that were different in molecular structure. The results of this study demonstrate that QSRRs method using ANN techniques can generate a suitable model for prediction of gas chromatographic retention of pesticides.
Also the results obtained in this work indicate that the regression and ANN models exhibit reasonable prediction capabilities. Descriptors which appeared in the obtained QSRR models reveal that electronic interactions as well as steric parameters can be affected on the gas chromatographic retention time of pesticides.