Separation and determination of triadimefon and its metabolites triadimenol enantiomers in fruit puree by supercritical fluid chromatography.

A method was established for the separation and determination of triadimefon and its metabolite triadimenol enantiomer residues in major complementary fruit puree for infants and young children (banana puree, pineapple puree, and grape puree) by supercritical fluid chromatography. After the samples were extracted with acetonitrile and purified with a solid phase extraction cartridge, Acquity Trefoil CEL2 chiral chromatographic column was adopted for separation, and gradient elution was conducted at the flow rate of 1.0 ml/min under the mobile phase of supercritical carbon dioxide - 0.5% ammonia methanol, the detection wavelength was 220 nm and quantification was conducted with the external standard method. The limits of quantitation of triadimefon and triadimenol enantiomers were both 0.05 mg/kg, the linear ranges were 0.5-50 mg/L, and the linear correlation coefficients were greater than 0.9993. The recoveries in the spiked samples at 0.05, 0.2, and 3.0 mg/kg were from 80.1 to 106%, and the relative standard deviation reached 3.3-7.6%. The method is efficient, rapid, reproducible, and environmentally friendly, enabling accurate analysis of pesticide enantiomers, which can detect the enantiomer residues of triadimefon and its metabolite triadimenol in major complementary fruit puree for infants and young children.

Research method of rapid determination of chiral pesticide fenpropathrin enantiomers in fruit and vegetable puree by supercritical fluid chromatography.

A method is first established for the separation and determination of fenpropathrin enantiomer residues in apple puree, strawberry puree, and tomato puree considered a supplementary food for infants by supercritical fluid chromatography. After the sample was extracted with acetonitrile and cleaned up by a solid-phase extraction column, then it was separated by a CHIRALPAK AD-3 chiral column with gradient elution at a flow rate of 1.5 mL/min using methanol and supercritical carbon dioxide as the mobile phase, detected by ultraviolet detector at 230 nm wavelength and quantified with the external standard method. The limits of quantification of the two fenpropathrin enantiomers were both 0.2 mg/kg, the linear ranges were 1.0-20.0 mg/L with linear correlation coefficients greater than 0.9992, the recoveries in the spiked samples at 0.2, 0.4 and 2.0 mg/kg were from 80.6 to 105%, and the relative standard deviation reached 2.6-7.7%. This method has the advantages of convenient operation, good resolution, and environmental protection, which can satisfy the requirement of determination for fenpropathrin enantiomer residues in fruit and vegetable puree as supplementary food for infants.

Analytical research on the separation and residue of chiral pesticide triadimenol in fruit and vegetable puree.

In this paper, a method for the separation of triadimenol stereoisomers using ultra-performance convergence chromatography and an analytical method for the determination of triadimenol stereoisomer residues in pumpkin puree, apple puree, and tomato puree as a supplement for infants are established. Test samples were extracted with acetonitrile and successively purified with graphitized carbon black and Florisil column. Afterward, Acquity Trefoil AMY1 column was adopted for chiral separation of chromatographic column, and gradient elute was carried out with supercritical carbon dioxide-methanol as the mobile phase and with external standard method for quantitation. Results showed that the linearly dependent coefficient of the four kinds of triadimenol stereoisomers within 1.0 and 50 mg/L was greater than 0.9997, and the limit of quantitation of the four kinds of triadimenol stereoisomers was 0.05 mg/kg. Recovery experiment was carried out within 0.05 and 1.0 mg/kg scope, the recoveries were 81.0-107％, and the relative standard deviation was 2.3-7.6%. This method implemented the separation of triadimenol stereoisomers and its residue test in pumpkin puree, apple puree, and tomato puree as a supplement for infants, and it can provide reliable technical support for the analysis of pesticide residue and assessment of product quality.

Synthesis and identification of antigenic conjugates of podophyllotoxin.

AIM: To synthesize and identify artificial antigen of podophyllotoxin for the production of podophyllotoxin polyclonal antibody. METHODS: The hapten was synthesized by two different chemical approaches and characterized by TLC, IR, NMR, and MS. Mixed anhydride reaction (MAR) and active ester method (AEM) were used to couple the podophyllotoxin to carrier proteins (BSA and OVA). Characterization of artificial antigens was done by using spectroscopy and electrophoresis. The anti-podophyllotoxin polyclonal antibodies were obtained through immunizing rabbits. RESULTS: The results from IR, NMR and MS showed that 4-O-succinoyl podophyllotoxin (hapten) was successfully synthesized. The coupling molar ratios of the hapten and carrier proteins were 88.6 for Hapten-BSA1, 40.3 for Hapten-BSA2, 17.8 for Hapten-OVA1, and 54.2 for Hapten-OVA2. Hapten conjugates coupled with BSA yielded two sets of the specific and affinitive polyclonal antibodies. One set of antibodies showed an IC50 value of 2.21 microg.mL(-1) with a detection limit of 0.12 microg.mL(-1). CONCLUSION: Antigenic conjugates were artificially synthesized, and based on these artificial antigens, polyclonal antibodies against podophyllotoxin were raised from rabbits immunized with two different immunogens and characterized with an indirect ELISA format.

Development of an enzyme-linked immunosorbent assay for podophyllotoxin.

A competitive indirect enzyme-linked immunosorbent assay (ciELISA) for podophyllotoxin was developed by using polyclonal antibody, and its suitability for the determination of this analyte in spiked water samples was studied. To avoid antibody production to the linker, the succinoyl-podophyllotoxin (hapten) mimicking the analyte was synthesized and conjugated with the carrier proteins bovine serum albumin (BSA) and ovalbumin (OVA) by mixed anhydride reaction (MAR) and active ester method (AEM). Polyclonal antibodies raised against Hapten-BSA(1) synthesized by MAR and Hapten-BSA(2) by AEM were screened and selected for the ciELISA. One set of antibodies from the rabbit M4440 immunized with Hapten--BSA(1) showed an I(50) value of 2.21 microg/mL with a detection limit of 0.12 microg/mL, and the other set from the rabbit M4469 immunized with Hapten-BSA(2) had an I(50) value of 0.7897 microg/mL with a detection limit of 0.0056 microg/mL. This assay showed the cross-reactivities with the structurally closely related compounds. Recoveries from the podophyllotoxin-fortified tap water in the assay were in the range of 72--115%. A good correlation between podophyllotoxin concentration measured by the ELISA and HPLC (R(2)=0.9924, Y=1.195X-0.257) was obtained from linear regression analysis. These results indicate that the ELISA could be a convenient and supplemental analytical tool for monitoring podophyllotoxin and its analogues in waters without previous extraction or cleanup.