Sequential Thin-Layer Chromatography of 2,4-D and Related Compounds

Abstract

Separations and identification of carboxylic herbicidal substances such as 2,4-dichlorophenoxyacetic acid, trichloroacetic acid, 2,4,5-trichlorophenoxyacetic acid and plant growth regulators such as benzoic acid, cinnamic acid, indole-3-acetic acid, β-naphthaleneacetic acid, β-naphthoxyacetic acid, phenoxyacetic acid have been made by sequential thin-layer chromatography on calcium sulphate layer with acetone, benzene, carbon tetrachloride, chloroform, ethyl acetate, dioxan, propanol as solvents and bromophenol blue as detector.     

Thin-Layer Chromatographic Studies of 30 Organic Acids on Calcium Sulphate

Abstract

Thin layer chromatographic behaviour of 30 organic acids on coatings of calcium sulphate and calcium sulphate containing charcoal, p-dimethyl-aminobenzaldehyde, flyash, silica gel G etc. has been studied. Farm chemicals: plant growth regulators (benzoic, cinnamic, gallic, β-naphthalene acetic, β-naphthoxy acetic and indole-3-acetic acids) and herbicides (phenoxy acetic acid) have been separated from one another and from several other organic acids.     

Determination of Phenoxy Acid Pesticides in Frog and Fish Tissues by Gas Chromatography-Mass Spectrometry

A gas chromatography-mass spectrometric GC-MS method has been developed for the determination of 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) in frog and fish tissues. After homogenization and sonication of 5 g samples, purification was achieved by a liquid phase extraction procedure using methyl-tert-butyl ether. The extract was reacted for 30 min at 80 °C with 10 % H₂SO₄ in methanol to form the corresponding methyl esters, which were simultaneously extracted with petroleum ether, and analysed by GC-MS in selected ion monitoring mode. Detection limits were 1.0 and 0.5 μg. kg^?1 for 2,4-D and 2,4,5-T respectively in tissue samples and the calibration curves showed good linearity (r ≥ 0.999). Twenty-five frog samples and forty-six fish samples from various regions in Korea were analyzed. 2,4,5-T was detected up to a maximum concentration of 16.2 μg kg^?1 in frogs and fish. The developed method may be valuable for the national monitoring project of endocrine disruptors (EDs) in biota.     

Preparation of Amides of Carboxylic Acid Herbicides for Gas Chromatographic Analysis

Abstract

Amides of 14 carboxylic acid herbicides were prepared by reacting the free acid with the amine in toluene for 1 hr at 80[ddot]C in the presence of PCl₃ or P₂I₄. The acids include phenoxyacetic acids, arylacetic acids, and benzoic acids. Aniline, o-toluidine, 3,5-bis(trifluoromethyl)aniline, piperidine, and tetrahydroquinoline were the amine components. Excess of reagents and by-products of the reaction were removed by partitioning into aqueous acid and base. Retention times relative to 2,4-D anilide on 1% OV-22 and FSOT RSL-150 columns are listed for the anilides and should be useful for confirmation purposes. The anilides of 2,4-D, silvex and 2,4,5-T were obtained in better than 90% yield.     

High-Performance Liquid Chromatographic Determination of the Metabolites of the Potato Glycoalkaloids, α-Chaconine and α-Solanine,in Potato Tubers and Potato Products

Abstract

A high-performance liquid chromatographic method has been developed to separate and quantify the metabolites, γ-chaconine, β₁-and β₂-chaconine, γ-solanine and β₂-solanine, of the potato gly-coalkaloids α-chaconine and α-solanine in potatoes and potato products. A carbohydrate analysis column and a solvent system of tetrahydrofuran-water-acetonitrile (55:8:37) were employed for the separation. Flow rate was 1.1 ml/min and the compounds were monitored at 215 nm. β₂-chaconine (0.63 mg to 29.75 mg/100 g dried weight) was present in all samples whereas the other glycosides of α-chaconine were only detectable in the animal feed products. It appears that some of the animal feeds may contain trace amounts of γ-solanine and an unknown which maybe β₁-solanine. Limit of detection for all glycosides was 0.05 μg/μl. Elution time for all the lower glycosides of α-chaconine was 8 min versus 16 min for the α-solanine group. These metabolic compounds were confirmed using thin-layer chromatography.     

Chromatographic Studies of 34 Organic Acids on Papers Impregnated with Hydroxides of Aluminium and Cadmium

Abstract

Papers impregnated with aluminium hydroxide and cadmium hydroxide have been used for the chromatographic separation of organic acids exist in various biological materials, soil and water. The following important separations: cinnamic acid from hippuric acid; benzoic and m-nitrobenzoic acids from gallic, β-naphthalene acetic, β-naphthoxy acetic, phthalic, quinic and salicylic acids; and salicylic acid from citric, cis-aconitic, malic, quinic, tartaric and trans-aconitic acids can be achieved in common electrolytes (Cd(NO₃)₂, KI, NaCl, NH₄Cl) solution.

Hydroxides¹ show amphoteric behaviour i. e. they may exchange either cations or anions depending upon the pH of the solution, and t h i s may be shown by the following ionic equilibria.     

Quantitative Separation of Citric Acid From Trichloroacetic Acid on Plates Coated with Calcium Sulphate Containing Zinc Oxide

Abstract

Thin-layer chromatographic behaviour of ten acids on coating of calcium sulphate containing ammonium molybdate, aluminium oxide, calcium carbonate, copper sulphate, ferric chloride, magnesium sulphate, phthalic anhydride, titanium oxide, zinc oxide etc. has been studied. Quantitative separation of citric acid from trichloroacetic acids has been achieved on calcium sulphate containirig zinc oxide in ethyl acetate. Herbicide, trichloroacetic acid can be separated from plant growth regulators such as indole-3-acetic, β-naphthaleneacetic and β-naphthoxy acetic acids and from other organic acids.     

A Fast,Simple Method for Analysis of Phenoxy Acid Salt and Ester Formulations by High Performance Liquid Chromatography

Abstract

Salt formulations of 2,4-D (2,4-dichlorophenoxyacetic acid), 2,4,5-T (2,4,5-trichlorophenoxyacetic acid) and dichlorprop [2-(2,4-dichlorophenoxy)propanoic acid] have been analysed by reversed-phase HPLC using a C18-column with 50:50 (v/v) acetonitrile/2% acetic acid as eluant. Internal and external standard HPLC methods are compared.

Ester formulations of 2,4-D and 2,4,5–T are analysed, without hydrolysis, on the same column using 60:40 (v/v) acetonitrile/2% acetic acid as eluant. The method has been used in this laboratory to determine free phenoxy acid in ester formulations, and for the identification of esters in mixed ester formulations.

The methods are fast and accurate, and offer some advantages over previously-described methods.     

Determination of the Pesticides MCPA, 2,4,5-T,and 2,4,5-T-Isopropyl Ester by Low Temperature Phosphorimetry

Abstract

Sensitive low temperature phosphorimetric methods for the determination of the pesticides MCPA, 2,4,5-T, and 2,4,5-T-isopropyl ester in EPA solvent have been developed. The minimum detectable amounts are 0.1 p.p.m. for both 2,4,5-T formulations and 0.2 p.p.m. for MCPA. The ranges in linearity of the analytical calibration graphs are 0.2–60, 0.5–60, and 0.5–50 p.p.m. for 2,4,5-T, 2,4,5-T-isopropyl ester, and MCPA respectively. The procedure for 2,4,5-T has been applied to the analysis of a solid commercial formulation.     

Development and Comparative Study of Different Immunoenzyme Techniques for Pesticides Detection

Abstract

Different ELISA techniques have been developed for the detemination of four widely used pesticides: 2,4-dichlorophenoxyacetic acid (2,4-D), 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), simazine and atrazine. Dependences between the assay scheme and the limiting detectable concentration of the pesticide were studied. The cases of preferential applying of the scheme with immobilized antibodies or one with immobilized pesticide-protein conjugate have been revealed. The following approaches resulting in lowering of ELISA sensitivity were proposed: preliminary incubation of the tested sample with antibodies, immobilization of antibodies via staphylococcal protein A, usage of monovalent fragments of antibodies instead of native ones and chemical modification of the pesticide molecules in the sample. Optimal combinations of these approaches permitted to lower the detection limit of the assays in about 5–30 times. The achieved sensitivities were 3 ng/mL for 2,4-D, 5 ng/mL for 2,4,5-T, 0.05 ng/mL for simazine, and 0.1 ng/mL for atrazine, being acceptable for purposes of ecological monitoring.     

Quantitative Determination of Miconazole in Creams by Second Order Derivative Spectrophotometry

ABSTRACT

A derivative spectrophotometry was developed to determine miconazole in cream formulations that contain benzoic acid as preservative. The procedure was based on the linear relationship in the range 100-500 μg ml^?1 between the drug concentration and the second derivative amplitudes at 276 nm. Results of the recovery experiments performed on various amounts of benzoic acid and of the determination of miconazole in cream confirmed the applicability of the proposed method to complex formulations.     

A New Stereospecific Synthesis of 1,2,4-Trideoxy-1,4-Imino-D-Erythro-Pentitol

ABSTRACT

1,2,4-Trideoxy-1,4-imino-D-erythro-pentitol [(2R,3S)-3-hydroxy-2-hydroxyme-thylpyrrolidine] (4) was synthesised from 2,5-di-O-tosyl-D-ribono-1,4-lactone in 42% overall yield. The key steps were deoxygenation at C-2 and a stereospecific inversion of the configuration at C-4. Compound 4 inhibited α-D-glucosidase (K_i = 25 μM) and β-D-glucosidase (K_i = 80 μM).     

Determination of indole-type phytonutrients in cruciferous vegetables

Abstract

Consumption of cruciferous vegetables has been associated with a low risk of developing cancer. Indole-type phytonutrients, derived from enzymatic hydrolysis of glucobrassicin, exhibit cancer-preventive properties and occur in all vegetables of the Brassicaceae family. A LC-Q-TOF-MS methodology was developed and applied in extracts from seven cruciferous vegetables allowing the rapid determination of indole-3-carbinol, indole-3-carbaldehyde, ascorbigen, indole-3-acetic acid and indole-3-acetonitrile. The novel method described herein, was validated and is characterized by low detection limits and excellent linearity. The simultaneous determination of indole-type phytonutrients in turnip and radish was performed for the first time.     

Synthesis,Characterization, Thermal,and Antibacterial Studies of Organotin(Iv) Complexes of Indole-3-Butyric Acid and Indole-3-Propionic Acid

Abstract

Six organotin(IV) complexes of type Me₂SnL₂, Bu₂SnL₂, and Ph₃SnL [where L = indole-3-butyric acid (1, 2 and 3) or indole-3-propionic acid (4, 5 and 6)] have been synthesized by the reactions of the corresponding diorganotin(IV) oxide and triphenyltin(IV) hydroxide with respective indole-3-butyric acid (IBH) or indole-3-propionic acid (IPH) in the desired molar ratios of 1:2/1:1. All of the compounds have been characterized by elemental analysis, IR, ¹H NMR, ¹³C NMR, and ¹¹⁹Sn NMR spectroscopy. Thermal studies of all synthesized complexes have been carried out using thermogravimetry (TG) technique under a nitrogen atmosphere. The thermal decompositions for compounds Me₂SnL₂ and Bu₂SnL₂ occurred in two steps, whereas in compounds Ph₃SnL, it exhibited as three steps decomposition and resulted into the formation of pure SnO₂. The complexes were also screened against three gram-positive (Staphylococcus aureus, Staphylococcus epidermidis, and Micrococcus luteus) and three gram-negative (Escherichia coli, Pseudomonas aeruginosa, and Enterobacter aerogenes) bacteria using minimum inhibition concentration (MIC) method, and all of these complexes showed significant antibacterial activity.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional text, tables, and figures.]     

Chemical Studies on Tobacco Smoke. LXI. Volatile Pyridines: Quantitative Analysis in Mainstream and Sidestream Smoke of Cigarettes and Cigars

Abstract

A quantitative analytical method has been developed for volatile pyridines in tobacco smoke using pyridine- ¹⁴C as an internal standard. Mainstream and sidestream smoke are trapped in 0.05 N sulfuric acid anti partitioned with chloroform. The acidic portion is then concentrated, adjusted to pH 3 and extracted with chloroform. Methanol and a trace of 2N sulfuric acid are added to this chloroform portion and the mixture is carefully concentrated.

A trace of sodium hydroxide is added and the final concentrate is analyzed by gas chromatography. Twenty-one volatile pyridines have been identified. The mainstream stroke of a popular. 85-mm U.S. cigarette without filter tip contained the following major pyridines: 33.4 μg pyridine, 12.3 μg α-picoline, 24.2 μg. β+γ-picoline, 7.6 μg 3-ethylpgridine, 5.9 μg: 4-ethylpyridine, and 23.3 μg 3,4-lutidine + 3-vinylpyridine. The sidestream smoke of this cigarette contained up to 28 times higher concentrations of pyridines.

Volatile pyridines were also determined in the mainstream smoke of other non-filter cigarettes, filter cigarettes, little cigars and, a non-tobacco cigarette. Of special interest were the much greater quantities of volatile pyridines in the mainstream and sidestream of cigars in comparison to those of cigarettes. The ratio of pyridines in sidestream to those in mainstream was 5 to 50 in large cigars. Selective filtration was observed with both cellulose acetate and charcoal filter tips. The analytical method resulted in reproducible values for pyridine, with an average recovery rate of more than 90%. In addition to pyridines, two pyrazines were also isolated from the smoke. Processed tobacco contained minute amounts of some volatile pyridines.     

1H NMR Study of Methyl O-Acetyl-α-and-β-D-Xylopyranosides Conformational Studies and Non Additivity of 1H-Shift Increments

Abstract

¹H NMR spectra of the complete series of fully and partially acetylated methyl α-and β-D-xylopyranosides have been studied. The α-anomers occur exclusively in ⁴C₁ chairs but the ¹C₄ chair becomes increasingly populated in the β-forms especially when the OH-3 is not acetylated. Increments used for the prediction of the chemical shifts of ring protons are discussed and compared with the literature data. The predictability for changes in shifts upon acetylation is poor.     

A new isoprenyl phenyl ether compound from mangrove fungus

A new isoprenyl phenyl ether, 3-hydroxy-4-(3-methylbut-2-enyloxy)benzoic acid methyl ester (1), together with 4-hydroxybenzoic acid (2), 2-hydroxy-6-methylbenzoic acid (3), and 4-hydroxy-3-methoxybenzoic acid (4) were isolated from Mangrove fungus (No. B60) from the South China Sea. The structures of the compounds were established on the basis of NMR spectroscopic and mass spectrometric data. In the preliminary bioassay, compound 1 exhibited antibacterial and antifungal activities. Compound 1 also inhibited cytotoxicity to the hepG2 cell line with an IC₅₀ value of 10.0 μg/mL. Published in Khimiya Prirodnykh Soedinenii, No. 4, pp. 313–314, July–August, 2007.     

固相萃取-超高效液相色谱-串联质谱法测定人尿中苯氧乙酸除草剂和有机磷、拟除虫菊酯农药代谢物北大核心CSCD

基于96孔固相萃取-超高效液相色谱-串联质谱法,建立了人尿中2种苯氧乙酸除草剂、2种有机磷农药代谢物和4种拟除虫菊酯农药代谢物的测定方法。通过对液相色谱条件、质谱条件和样品前处理过程的系统优化,实现了在16 min内对8种目标分析物的分析测定。具体方法:1 mL尿液经β-葡萄糖醛酸酶酶解过夜,Oasis HLB 96孔固相萃取进行目标分析物的提取净化,甲醇洗脱;以0.1%(体积分数)乙酸乙腈和0.1%(体积分数)乙酸水作为流动相,Acquity BEH C_(18)作为分析柱进行色谱分离;负离子电喷雾(ESI-)多反应监测(MRM)模式下检测目标化合物,同位素内标法定量。2,4-二氯苯氧乙酸(2,4-D)、2,4,5-三氯苯氧乙酸(2,4,5-T)2种苯氧乙酸除草剂和3-苯氧基苯甲酸(3-PBA)、4-氟-3-苯氧基苯甲酸(4F-3PBA)、反式二氯乙烯基二甲基环丙烷羧酸(trans-DCCA)3种拟除虫菊酯农药代谢物在0.1~100μg/L内、对硝基苯酚(PNP)、3,5,6-三氯-2-吡啶酚(TCPY)2种有机磷农药代谢物、顺式二氯乙烯基二甲基环丙烷羧酸(cis-DCCA)1种拟除虫菊酯代谢物在0.2~100μg/L内线性关系良好,相关系数均大于0.9993;方法检出限为0.02~0.07μg/L,方法定量限为0.08~0.2μg/L;低、中、高3个水平下的加标回收率为91.1%~110.5%,日内精密度为2.9%~7.8%,日间精密度为6.2%~10%。应用该方法测定了214份尿液样本。结果显示除2,4,5-T外,其余7种目标分析物均有检出。TCPY、PNP、3-PBA、4F-3PBA、trans-DCCA、cis-DCCA、2,4-D的检出率为2.8%~99.1%。检出浓度(中位值)由高到低分别是2.0μg/L(TCPY)、1.8μg/L(PNP)、0.99μg/L(trans-DCCA)、0.81μg/L(3-PBA)、0.44μg/L(cis-DCCA)、0.35μg/L(2,4-D)和未检出(4F-3PBA)。该方法操作简便,定量准确,灵敏度高,每批次可完成96个样品测定,适用于人尿中多种农药及农药代谢物的批量分析测定。     

Determination of the Phytohormone Indole-3-Acetic Acid by Synchronous Derivative Spectrofluorometry Following Acetic Anhydride Derivatization

Abstract

The very selective fluorogenic reaction of indole-3-acetic acid (IAA) with acetic anhydride, acid catalyzed, is used to perform an improved fluorometric method for the determination of nanogram amounts of IAA. The synchronous derivative approach used in this work provides significant advantages in the more relevant analytical figures of merit, especially in sensitivity and precision.     

Novel and enantioselective syntheses of (R)- and (S)-3-hydroxy-4-(2,4,5-trifluorophenyl)butanoic acid: a synthon for sitagliptin and its derivatives

A new synthetic strategy for (R)- and (S)-3-hydroxy-4-(2,4,5-trifluorophenyl)butanoic acid, a building block in the preparation of sitagliptin and its derivatives, was developed. Pd(OAc)₂ catalyzed coupling of 2,4,5-trifluoro-1-iodobenzene with allyl alcohol gave 3-(2,4,5-trifluorophenyl)propanal in a yield of 95%. l-Proline catalyzed reaction of the 3-phenylpropanal (in only 1.2 molar equiv) with nitrosobenzene followed by reduction with NaBH₄ and Pd/C catalyzed hydrogenation gave (R)-3-(2,4,5-trifluorophenyl)propane-1,2-diol with >99% ee and 65% yield. Selective tosylation of primary hydroxyl group of the 1,2-propandiol unit followed by cyanide displacement afforded (R)-3-hydroxy-4-(2,4,5-trifluorophenyl)butanenitrile (80%). The nitrile was converted to the title β-hydroxy acid under basic hydrolysis in a yield of 90%. Thus, (R)-3-hydroxy-4-(2,4,5-trifluorophenyl)butanoic acid was prepared enantioselectively from the starting material in four steps and 45% overall yield. The reaction sequence was repeated with d-proline as the catalyst to give (S)-3-hydroxy-4-(2,4,5-trifluorophenyl)butanoic acid in 45% overall yield and >99% enantiomeric excess.