High-performance liquid calibration curves

Hasegawa et al. [76] measured miconazole serum concentration by a high performance liquid chromatographic method. The authors assessed whether the internal standard method produced an intra-assay error and found that the method gave more precise and more reproducible results compared to the absorption calibration curve method. With 0.5 pg/mL of miconazole, the coefficient of variation produced by that method was 3.41%, whereas that of the absorption calibration curve method was 5.20%. The concentration of absorptions calibration curve method showed higher values than the internal standard method. This indicated that the internal standard method was far more precise in measuring the miconazole serum concentrations than the absorption calibration curve method. 

De Ruiter et al. [4] observed that photochemical decomposition by ultraviolet irradiation of dansyl derivatives of chlorinated phenolic compounds in methanol-water mixtures led to the formation of highly fluorescent dansyl-OH and dansyl-OH3 species. The optimal irradiation time was 5.5s. This reaction was utilised in a post-column photochemical reactor in the high performance liquid chromatography determination of highly chlorinated phenols in river water. The method calibration curve (for dansylated pentachlorophenol) was linear over three orders of magnitude. 

Diclofenac sodium concentrations in aqueous solutions and in plasma were estimated by means of a published high performance liquid chromatographic technique ( 1 ). This method had a detection limit of 5 ng/ml and gave replicate values within 10% at levels above 20 ng/ml. Calibration curves were linear throughout the range of measured concentrations. 

Arun et al. [30] developed and validated a rapid high-performance liquid chromatographic method for the estimation of buclizine hydrochloride in tablet dosage form. The stationary phase used was precoated silica gel 60 F254. The mobile phase used was a mixture of methanol chloroform ammonia (8 1 1). The detection of spots was carried out at 234 nm. The method was validated in terms of linearity, accuracy, precision, and specificity. The calibration curve was linear between 100 and 700 ng/spot. The limit of detection and the limit of quantification were 20 and 100 ng/spot, respectively. The method can be used to determine the drug content of tablet dosage formulation. 

Indapamide can be analyzed in blood, plasma and urine by HPLC and fluorescence methods. A specific and sensitive assay method for the analysis of indapamide in urine, blood and plasma was developed (31). The method uses a 250 x 4.6 mm i.d. Zorbax ODS (5 pm particle size) column and a mobile phase of 0.1 M sodium acetate buffer (pl =3.6)/acetonitrile at a ratio of 65/35 (v/v). This method uses an internal standard of sulfanilanilide. Calibration curves obtained by plotting the ratio of the peak height of indapamide to that of sulfanilanilide versus the concentration of indapamide were linear over the concentration ranges of 25-200 ng/mL for plasma and 50-400 ng/mL for blood and urine using UV detection at 241 nm. Another publication reports a high performance liquid chromatographic assay method for monitoring indapamide and Its major metabolite in urine (32). 

Recent developments in the sensitivity and resolution of NMR spectrometers permitted us to use one as a real-time detector for high-performance liquid chromatography as demonstrated in recent review articles.332,333 Recently we developed an on-line GPC/NMR system in which a 500-MHz 1H NMR spectrometer was used as a detector.334-339 By using on-line GPC/NMR the molecular weight of a polymer can be determined without a calibration curve if the polymer sample contains a known amount of end-group per polymer molecule. 

Standards a stock solution (2.5 mM) of SN-38 glucuronide (kindly supplied by Yakult Honsha Co. Ltd.) is dissolved in 5 mL of methanol. A working solution (0.5-250 iiM) for calibration curves is prepared by the serial dilution of the 2.5 mM stock solution with high-performance liquid chromatography (HPLC) elution buffer. 

Quantitation of 1. Quantitation was performed by high performance liquid chromatography using a Hewlett Packard 1050 system. One mg of root exudates were dissolved in I mL of acetonitrile. Components of the root exudates was separated on an Alltech EPS CIS column 100 A 3p (ISO mm length x 4.5 mm internal diameter). The mobile phase was eluted at a flow rate of 2 mL/min as follows (solvent A is 2.5% acetic acid in water, solvent B is acetonitrile) 0-15 min 45% A / 55% B isocratic 15-22 min linear gradient from 55% to 100% B 22-25 min 100%B 25-26 min 100% to 55% B 26-30 min 45% A / 55% B isocratic. The peaks were monitored at X280 nm, and the volume of injection was 20 pL. Quantitation was based on a calibration curve of an external standard of purified 1. 

Seppanen, C.M., Rahmani, M., and Csallany, A.S., Simultaneous determination of chlorophylls, pheophytins, beta-carotene, tocopherols, and tocotienols in olive and soybean oils by high-performance liquid chromatography. J. Food Sci., 68, 1644, 2003. Torsi, G., Chiavari, G., and Lippolis, M.T., Quantitation without calibration curves using HPLC with nondestructive detectors, LC-GC Inti., 5, 37, 1992. 

Fig, 4. A typical size exclusion calibration curve and chromatogram of the separation of a protein mixture. Column BIOSEP-SEC-S3000. Mobile phase pH 6.8 phosphate buffer. Detector UV abs. at 280nm. Reproduced from W.J. Lough I.W. Wainer (eds), High Performance Liquid Chromatography, 1996, first published by Blackie Academic Professional,... 

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