ODS column chromatography

Another example describes the isolation of three hexasaccharides (I, HI and V) and two trisaccharides (II and IV) from the leaves of Agave fourcroydes (36). Air-dried leaves were extracted with methanol and applied to a column of Diaion HP-20. The fraction eluted with 100% methanol was partitioned between ethyl acetate and 10% aqueous methanol and the aqueous phase was further extracted with re-butanol. This re-butanol-soluble fraction was subjected to ODS column chromatography and eluted with gradient mixtures of 50-100% methanol in water. Rechromatography over ODS of the 80% methanol-eluted fraction using gradient mixtures of 60-75% methanol in water furnished... 

Dibenzyl-14-crown-4 (lithium ionophore VI 6,6-dibenzyl-l,4,8,ll-tetra-oxa-cyclo-tetradecane) [106868-21-7] M 384.5, m 102-103°. Dissolve in CHCI3, wash with saturated aqueous NaCl, dry with MgSOa, evaporate and purify by chromatography on silica gel and gradient elution with C6Hg-MeOH followed by preparative reverse phase HPLC on an octadecyl silanised silica (ODS) column and eluting with MeOH. It can be crystd from MeOH (v Br 120 cm , C-O-C). [7 Chem Soc Perkin Trans 1 1945 1986.]... 

FIGURE 4.22 HPLC chromatogram of amino acids employing precolumn derivatiza-tion with OPA. Chromatography was carried out on an Ultrasphere ODS column using a complex tetrahydrofuran methanol 0.05 M sodium acetate (pH 5.9) 1 19 80 to methanol 0.05 M sodium acetate (pH 5.9) 4 1 gradient at a flow rate of 1.7 mL/min. 

Quantitative HPLC analysis was carried out on a Spectraphysics 8720 chromatography system, a rapid scan detector by Barspec on a Zorbax ODS column with acetonitrile water 75/25 as the eluent. 

The analysis of amino acids involves chromatographic issues similar to those encountered in analysis of simple amines. Underivatized amino acids have, with a few exceptions, weak UV absorbance and a strong tendency to interact with stationary phases in undesirable ways. Underivatized amino acids are normally separated with ion exchange chromatography, then visualized post-column by reaction with ninhydrin, o-phthaladehyde (OPA), or other agents. Underivatized tryptophan and the metabolites kynurenine, 3-hydroxykynurenine, kynurenic acid, and 3-hydroxyanthranilic acid, were separated on a Partisphere 5-p ODS column with fluorescent detection.121... 

Ito, K. and Kumamaru, T., Separation and detection of common mono- and divalent cations by ion chromatography with an ODS column and conduc-tivity/UV detection, /. Chromatogr. A, 850, 247, 1999. 

Achiral-chiral chromatography has also been accomplished using subcritical fluid chromatography (Phinney et al., 1998). In this work, the structurally related [3-blockers, 1,4-benzodiazepines, and two cold medicines were separated using methanol or ethanol modified carbon dioxide mobile phases. The (3-blockers were separated using cyanopropyl and Chiracel OD columns connected in series. Likewise, an amino bonded phase and Chiracel OD column were used for the separation of the 1,4-benzodiazepines. Guaifenesin and phenylpropanolamine from cough syrup were separated on cyanopropyl and Chiralpak AD columns in series. 

Thiocyanate Human urine, saliva Dilution with water then filtration (0.45 pm) Ion chromatography utilizing ODS column coated with cetyl-dimethylamine and with UV absorbance (210 nm) detection 20 ng/mL 95-101 Michigami et al. 1992... 

Size-exclusion chromatography combined with RP-HPLC-MS was employed for the separation of pyranoanthocyanins from red wine. Wine samples (10 ml) were acidified with 3 M HC1 to pH 1 then sodium bisulphite was added at a concentration of 400 g/1. After 15 min reaction time the treated wine was loaded into a gel column (200 X 15 mm i.d.). Pigments were eluted with 95 per cent ethanol followed with 100 per cent methanol. The various fractions were acidified to pH 1, concentrated and redissolved in water. HPLC-DAD was carried out in an ODS column (150 X 4.6 mm i.d. particle size 5 /nn) at 35°C. Solvents were 0.1 per cent aqueous TFA (A) and ACN (B). The gradient started with 10 per cent B for 5 min to 15 per cent B for 15 min isocratic for 5 min to 18 per cent B for 5 min to 35 per cent B for 20 min. The flow rate was 0.5 ml/min and analytes were detected at 520 nm. MS conditions were sheath and auxiliary gas were a mixture of nitrogen and... 

The anthocyanin profile of the flowers of Vanda (Orchidaceae) was investigated with a similar technique. Flowers (2 kg) were extracted with 101 of methanol-acetic acid-water (9 l 10,v/v) at ambient temperature for 24 h. The extract was purified by column chromatography, paper chromatography, TLC and preparative RP-HPLC. Analytical HPLC was carried out in an ODS column (250 X 4.6 mm, i.d.) at 40°C. Gradient conditions were from 40 per cent to 85 per cent B in 30 min (solvent A 1.5 per cent H3P04 in water solvent B 1.5 per cent H3P04, 20 per cent acetic acid and 25 per cent ACN in water). The flow rate was 1 ml/min and analytes were detected at 530 nm. The chemical structures of acylated anthocyanins present in the flowers are compiled in Table 2.90. The relative concentrations of anthocyanins in the flower extracts are listed in Table 2.91. It can be concluded from the results that the complex separation and identification methods (TLC, HPLC, UV-vis and II NMR spectroscopy, FAB-MS) allow the separation, quantitative determination and identification of anthocyanins in orchid flowers [262],... 

T. Cserhati, E. Forgacs, H. Morais and C. Ramos, Use of a microbore ODS column for the separation of paprika (Capsicum annuum) pigments by high performance liquid chromatography. Pol. J. FoodNutr. Sci. 11/52 (2002) 11-13. 

Sulphonated azo dyes were separated and quantitated in various food products by ion-pair liquid chromatography with DAD and electrospray MS detection. The chemical structure of sulphonated azo dyes included in the investigation are shown in Fig. 3.36. Dyes were separated in an ODS column (125 X 2.0 mm i.d. particle size 5 pm) using gradient elution. An aqueous solution of 3 mM triethylamine (pH adjusted to 6.2 with acetic acid) and methanol... 

The mixture was extracted with diethyl ether (three times). The combined organic layers were washed with brine and dried over sodium sulfate. After concentration in vacuo, the residue was purified by silica gel flash column chromatography (hexane/ethyl acetate = 20/1-3/1) to give (5)-l (426.3 mg, 74%, 98% ee) as a colourless solid. The enantiomeric excess of (5)-l was determined by chiral stationary-phase HPLC analysis DAICEL CHIRALCEL OD-H, j-PrOH/hexane 1/4, flow rate l.OmLmin tR 14.0 min [(R)-isomer)] and 21.3 min [(5)-isomer), detection at 254 nm]. ... 

The removal of triglycerides from the food sample by saponification provides the opportunity to utilize reversed-phase chromatography. The unsaponifiable matter is conventionally extracted into a solvent [e.g., diethyl ether/petroleum ether (50 50) or hexane] that is incompatible with a semiaqueous mobile phase. It then becomes necessary to evaporate the unsaponifiable extract to dryness and to dissolve the residue in a small volume of methanol (if methanol is the organic component of the mobile phase). For the analysis of breakfast cereals, margarine, and butter, Egberg et al. (153) avoided the time-consuming extraction of the unsaponifiable matter and the evaporation step by acidifying the unsaponifiable matter with acetic acid in acetonitrile to precipitate the soaps. An aliquot of the filtered extract could then be injected, after dilution with water, onto an ODS column eluted with a compatible mobile phase (65% acetonitrile in water). 

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