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Chromatographic scince series - Cazes J.

Cazes J. Chromatographic scince series - Marcel Dekker, 1996. - 1098 p.
ISBN 0-8247-9454-0
Download (direct link): сhromatography1996.pdf
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Culvutaria lunata 10-30 Plants 110
Soil
Pesticides 787
788
Fodor-Csorba
a florisil, celite, and charcoal mixed stationary phase. The spots were extracted and quantitated by UV spectrophotometry (106).
Dinitro-octyl-phenyl-crotonate is the active ingredient of Karathan 50 EC. The isomers of this fungicide, along with dinitro-octyl-phenol, mononitro-octyl-phenol isomers, and other impurities, are present in the commercial fungicide. These compounds were investigated on modified silicas as reversed-phase TLC sorbents. Modifiers containing chloropropyl and chloromethyl groups had better properties than the aminopropyl derivative because of their greater adsorptive power (107) (Table 8).
Triform (Saprol) was semiquantitatively determined in soil and water samples by two-dimensional TLC using silver nitrate-ammonia spray reagent (19).
The research for new fungicidal compounds forms the second part of this section. Some compounds having nematocidal activity were isolated by preparative TLC from leaves of Piper beetle (piperacae). Their biological activity was checked on the same layer using Phithium ultimum and Cladosporium cucumerinum strains (108) (Table 8).
l-phenyl-2-nitro-3-acetoxyprop-l-ene has fungicidal activity. This compound acts by blocking the thiol groups in the proteins of fungi. This interaction was studied between the above-mentioned fungicide and amino acids or glutathion by reversed-phase charge-transfer TLC (109). This method is an example of the use ofTLC as the basic method in mode-of-action studies.
Organotin fungicides were extracted from plants and soils with benzene. A sensitive biological method was developed for their detection on TLC plates based on their biological activity using Culvularia lunata strains (110). This method makes visible as little as 10-30 ng of fungicide (Table 8). New methods were listed in several reviews published recently (25a-e).
F. Pyrethroids
Synthetic pyrethroids constitute a new generation of pesticides that have been developed as good substitutes for persistent organochlorine and toxic organophosphorus insecticides.
Deltamethrin (XX, Fig. 7) has been developed for control of insect pests of crops, livestock, and humans. Deltamethrin and its trans isomer have been reported to be highly active against insects, but only deltamethrin is of high acute toxicity to mammals (111). Some isomerization takes place when deltamethrin is exposed to light. The eight possible isomers of deltamethrin were isolated from environmental samples and separated by TLC (112). The cis and trans isomer pairs were resolved in a benzene-carbontetrachloride (1:1) mixture (Table 9) after three developments in the same direction.
Figure 7 Pyrethroids. XX, deltamethrin; XXI, fenvalerate.
Table 9 Pyrethroids
Compound
Stationary phase
Mobile phase
Deltamethrin
|aS,lR,3R-m]
[aR.lS,3S-c«] |aR,lR,3R-m] [aS, IS.3S-cij] [aS, IR,3S-/ran.s] [aR,lS,3R-(rflnsl |aR,lR,3S-rra/is] [aS, lS,3R-/rani] l4C-deltamethrin and metab.
Baker-flex
Silica gel IB2-F
Silica gel F254 (Whatman)
(1) Benzene-CCl4 (1 : 1).
3 x development
(2) Hexane-ether (4:1),
3 x development
Benzene saturated with formic acid-ether (10:3)
Deltamethrin
Silica gel (I) CHCI^-acetic acid (99: 1)
(Whatman) (2) Toulene-hexane (80 : 20)
C-fenvalerate
isomers
S,S;R,R
S,R;R.S
l4C-fenvalerate CPIA
4'-HO-fenvalerate
CONH2-fenvalerate P Bacid 4'HO-P Bacid
Silica gel F254 (Merck)
Silica gel F, (Merck)
Hexane-ether (20 : 1), 6 x development
(1) Hexane-acetone-acetic acid
(25:25: 1)
(2) Toluene-ether-acetic acid
(75:25: I)
Diastereomers of Silica gel H_,S4
fenvalerate (Merck)
Decarboxyfenvalerate
Hexane-ether (20: I)
R, x 100
Detection
Sample
Ref.
(1) (2)
UV
Pasture
112
74
Forage
Litter
61
52
92
86
79
69
74
78
70
62
57
46
49
72
38
42
UV
Autorad.
UV
Autorad.
UV
Autorad.
Autorad.
Hen's liver
Kidney
Eggs
Albumen
Yolks
Cow. chicken liver, enzyme prep.
Lettuce
Beets
Wheat
113
114
115
16
(I)
47
54-57
49
41 (2)
42
3 - 35 38 16
Autorad.
Soil
Wheat
117
50 38
Pesticides 789
Table 9 (continued)
Compound
Stationary phase
Mobile phase
Chlorophenyl-'4C-
fenvalerate
4C-fenvalerate
Permethrin cis
Permethrin trans Cypermethrin cis Cypermethrin trans Decamethrin Fenvalerate
Silica gel 60 F25
Silica gel F254 (Merck)
(1) Hexane-acetone-acetic acid
(25:25: 1)
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