Thin-layer chromatographic technique for the separation and identification of carbamate pesticides in post mortem material

Thin Layer Chromatography with Post-Chromatographic Iodine-Azide Reaction for Thiuram Analysis in Food Samples

“…There was no need to find new chromatographic systems because several different ones had been already proposed for standards. [1][2][3][4][5][6][7][8][9][10][11] It was necessary to establish a good resolution of thiuram in food samples since the iodine-azide detection system is sensitive towards other thiols present in the samples (e.g., cysteine, glutathione) or substances, which react with iodine in an acid conditions (e.g., ascorbic acid). It appeared that dichloromethane was sufficient enough as a mobile phase to separate thiuram (R F ¼ 0.29) from other sulfur(II) compounds in apples as well as in apple (R F ¼ 0.20) and carrot (R F ¼ 0.0) juice samples.…”

“…The methods utilized for detection in TLC, such as visualization under 254 nm [4,5] with a TLC=HPTLC scanner, [6,7] iodine vapor, [8] fast blue B, [5] 2,6-dibromoquinone chlorimide [5] 2,6-dichloroquinone chlorimide, [9] Dragendorff reagent, [9] dithizone [9,10] copper(II) ions [9,10] procedures, gave a detection limit at the level of 0.2-20 nmol per spot. Only the enzymatic technique [11] enables lowering the detection limit to 80 pmol per spot.…”

“…[3] The most common method utilized for detection in TLC is visualization under 254 nm [4,5] and with a TLC=HPTLC scanner. [6,7] Most of the procedures cited in literature employed general (such as fast blue B, [5] 2,6-dibromoquinone chlorimide, [5] iodine vapor, [8] 2,6-dichloroquinone chlorimide, [9] Dragendorff reagent, [9] dithizone, [9,10] copper(II) ions [9,10] and enzymatic [11] procedures) rather than a specific detection reagent for thiuram. A great number of analyses require application of a selective and sensitive reagent for post-chromatographic detection.…”

TLC determination of airbone carbofuran and quinalphos for industrial hygiene purposes

“…Several solvent systemssuggested in other publication [4,5] were tested, but the benzenelrnethyl ethyl ketone (90 : 1Ovlv) system proved to be the most satisfactory for carbofuran and the ethyl acetatelbenzene (55 : 45 vlv) system for quinalphos. Carbofuran had an Rf-value of 0.27 and quinalphos one of 0.68.…”