High performance liquid chromatography isocratic

Procedure Flavonoids are then further purified with 2 ml of methanolic HC1 (2 N), followed by centrifugation (2 min, 15 600 g), hydrolyzation of 150 il of suspension in an autoclave (15 min, 120 C). A reverse osmosis-Millipore UF Plus water purification system is used in high performance liquid chromatography (HPLC) with an autosampler. After injections of 5 pg of samples, the mobile phases flow at a rate of 1 ml/minute with isocratic elution in a column at 30 C. 

The isocratic system (Fig. 1.2 (a)) provides an economic first step into high-performance liquid chromatography techniques. The system is built around a high-performance, dual-piston, pulse-free pump providing precision flow from 0.01 to 5ml min-1. 

M. Weissenberg, I. Schaeffler, E. Menagem, M. Barzilai and A. Levy, Isocratic non-aqueous reversed-phase high-performance liquid chromatography separation of capsanthin and cap-sorubin in red peppers (Capsicum annuum L.), paprika and oleoresin. J. Chromatogr.A 757... 

Lou, D.-W., Saito, Y., Zarzycki, P. K., Ogawa, M., and Jrrmo, K. (2006b). Isocratic separation of ginsenosides by high-performance liquid chromatography on a diol column at subambient temperatures. Ancd. Bioanal. Chem. 385, 96-104. 

Product ester ee was determined by isocratic normal-phase high-performance liquid chromatography using a Chiralcel OD-H (250 mm x 4.6 mm) column and a 98 % hexanes/2 % isopropanol mobile phase at 1.75 mL min and 25 °C. The undesired (/ )-ester and desired (5)-ester were quantified using their characteristic retention times of 10.3 min and 21 min respectively during elution. 

Lakshmana MK, Trichur TR. 1997. An isocratic assay for norepinephrine, dopamine and 5-hydroxytryptamine using their native fluorescence by high-performance liquid chromatography with fluorescence detection in discrete brain areas of rat. Anal Biochem 246 166-170. 

Pietta PG, Mauri PL, Gardana C, Benazzi L. Assay of soluble guanylate cyclase activity by isocratic high-performance liquid chromatography. J Chromatogr B Biomed Sci Appl 1997 690 343-347. 

High performance liquid chromatography (HPLC) apparatus (isocratic system) fitted with a 2-mL sample loop. 

SU Rehman. Rapid isocratic method for the separation and quantification of major phospholipid classes by high performance liquid chromatography. J Chromatogr 567 29-37, 1991. 

Acetonitrile-silver nitrate extracts of soil, partitioned with methylene chloride and cleaned up on silica gel, have been used in the high-performance liquid chromatographic determination of benfuracarb and carbofuran herbicides [204], McGarevy et al. [336] and Lin and Cooper [336] used optimised isocratic high-performance liquid chromatography with UV detection to determine Aldicarb and its metabolites in soil. 

High performance liquid chromatography in reversed phase mode was performed isocratically with 82% acetonitrile in water. Detection wavelengths of 254 and 280nm... 

A. R. Ivanov, I. V. Nazimov, and L. Baratova, Determination of biologically-active low-molecular-mass thiols in human blood. I. Fast qualitative and quantitative, gradient and isocratic reversed-phase high-performance liquid-chromatography with photometric and fluorescence detection, J. Chromatogr. A. 895, 157-166 (2000). 

Donovan SF, Pescatore MC (2002) Method for measuring the logarithm of the octanol-water partition coefficient by using short octadecyl-poly(vinyl alcohol) high performance liquid chromatography columns. J Chrom A 952 47-61 Du CM, Valko K, Bevan C et al. (1998) Rapid gradient RP-HPLC method for lipophilicity determination s solvation equation based comparison with isocratic methods. Anal Chem 70 4228-4234... 

Peroxidase-Catalyzed Polymerization of p-Cresol. Large scale polymerizations were carried out in a volume of 250 mL in a 500 mL round bottom flask at 25°C with stirring at ca. 250 rpm. p-Cresol (688 mg, 25 mM) was dissolved in 213 mL dioxane and 37 mL aqueous buffer, pH 7 (0.01 M phosphate) added to give a solution consisting of 85% (v/v) dioxane. Horseradish peroxidase (25 mg, free powder) was added and the reaction was initiated by the addition of 0.28 mL of 30% H2O2 (10 mM). The suspension (peroxidase is insoluble in 85% dioxane) immediately turned yellow and the reaction was allowed to proceed 15 min. The concentrations of p-cresol and reaction products were determined by high performance liquid chromatography (HPLC) with a Ci8-reverse phase column (Waters Associates, Milford, MA). The isocratic solvent used was acetonitrile water (56 44) with... 

Haghi, G. Hatami, A. 2010. Simultaneous quantification of flavonoids and phenolic acids in plant materials by a newly developed isocratic high-performance liquid chromatography approach. J. Agric. Food Chem. 58 10812 10816. 

Vanbeneden, N., Delvaux, E, Delvaux, ER. (2006). Determination of hydroxycinnamic acids volatile phenols in wort and beer by isocratic high-performance liquid chromatography using electrochemical detection. J. Chromatogr. A, 1136, 237-242. 

Thin-layer chromatography (TLC) is mainly applied in micropreparative taxoids separation [2-4]. Silica gel 6OF254 preparative plates are usually applied for this purpose. The problem of taxoids separation involves not only their similar chemical structure (e.g., paclitaxel versus cephalomannine) but also, due to different coextracted compounds usually encountered in crude yew extracts (polar compounds such as phenolics and nonpolar ones such as chlorophylls and biflavones), the separation is very difficult. The common band of paclitaxel and cephalomannine was satisfactorily resolved from an extraneous fraction in isocratic elution with ethyl acetate as a polar modifier [4] and n-heptane-dichloromethane as the solvent mixture and it was of suitable purity for high-performance liquid chromatography (HPLC) quantitative determination. 

---