A software package for the evaluation of peak parameters in an analytical signal based on a non-linear regression method

Scheeren, P.J.H.; Barna, P.; Smit, H.C.

doi:10.1016/s0003-2670(00)84410-4

Cited by 24 publications

(5 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Third, we affirm our acquisition rates were sufficient to predict N . The Nyquist theorem ensures fidelity of a Gaussian if seven points are acquired, , although studies on area determination recommend the acquisition of 10 or more points/standard deviation. − To preserve fidelity, the acquisition rate also should increase with decreasing S/N. These findings are only partly relevant, however, since our peaks are not Gaussians and we are concerned with N .…”

Section: Resultsmentioning

confidence: 99%

Quantitative Study of Concentration Overload, Peak Asymmetry, and Efficiency Loss in Micellar Electrokinetic Chromatography

Smith

Davis

2002

Anal. Chem.

View full text Add to dashboard Cite

An equation is derived for the velocity of a thin zone of specific analyte concentration in micellar electrokinetic chromatography. The velocity varies with analyte concentration, because micellar solubilization changes electrical conductivity, micellar electrophoretic mobility, and the partitioning of anabyte between mobile and micellar phases. Two studies based on a weakly and a strongly retained neutral analyte are made to test a limiting form of the equation in which the first two changes are ignored. In the first study, peak asymmetries are characterized and plate numbers are measured in two types of experiments: one of fixed surfactant concentration and variable analyte concentration and one of fixed analyte concentration and variable surfactant concentration. In the second study, the isotherm describing both experiment types is measured and interpreted by the Langmuir model to evaluate the velocity equation. The equation of continuity is solved numerically for the peak profiles governed by the velocity equation. In all but one case, a good agreement is found between theoretical and experimental peak asymmetries and plate numbers in both experiment types. An equation is derived for the relative change of analyte velocity caused by the Langmuir isotherm. The change depends on the relative migration time, micellar saturation, and retardation factor. The predicted velocity changes correlate well with peak asymmetries and efficiency losses.

show abstract

Section: Resultsmentioning

confidence: 99%

Quantitative Study of Concentration Overload, Peak Asymmetry, and Efficiency Loss in Micellar Electrokinetic Chromatography

Smith

Davis

2002

Anal. Chem.

View full text Add to dashboard Cite

show abstract

“…The data processing included correction for linear drift of the (digitized) detector signal and, in the case of correlation experiments, cross-correlation between the detector signal and a pattern close related to the injection pattern. 44 To determine the peak parameters, a peak-fitting procedure was applied to the correlogram or the electropherogram, using a nonlinear regression software package with a Fraser-Suzuki peak model 46 and a second-order polynomial describing the baseline. Noise levels, expressed as standard deviations, were calculated from the main baseline part of the correlogram or electropherogram.…”

Section: Methodsmentioning

confidence: 99%

“…To determine the peak parameters, a peak-fitting procedure was applied to the correlogram or the electropherogram, using a nonlinear regression software package with a Fraser−Suzuki peak model and a second-order polynomial describing the baseline. Noise levels, expressed as standard deviations, were calculated from the main baseline part of the correlogram or electropherogram.…”

Section: Methodsmentioning

confidence: 99%

A Micromachined Injection Device for CZE: Application to Correlation CZE

1997

View full text Add to dashboard Cite

A micromachined injection device is described, which can be connected to a fused-silica capillary. This allows injection without interrupting the current, which is an advantage in CZE and essential in correlation CZE. A typical property is the excellent connection, with low dead volume, between the capillary and the microchip. This results in very good repeatability of the peak parameters as is demonstrated by conventional electrokinetic injections. Correlation CZE experiments showed a considerable improvement in S/N ratio at high as well as at low concentrations. An 8-fold improvement in detection limit is achieved. The repeatability of peak height and peak area in correlation CZE was even better than obtained with conventional CZE.

show abstract

“…The required fitting flexibility was obtained by exponentially modifying a tailing peak model, i.e. the Fraser-Suzuki function (21). Profiles from rat samples were analyzed for insulin and PI; in subsequent analysis, peaks of insulin I and II and of PI I and II were counted separately and/or in combination.…”

Section: Calculationsmentioning

confidence: 99%

Effect of Glucose on Production and Release of Proinsulin Conversion Products by Cultured Human Islets1

Zambre

Ling

Hou

et al. 1998

The Journal of Clinical Endocrinology &Amp; Metabolism

View full text Add to dashboard Cite

Isolated human islets were examined for the rates of conversion and release of newly formed (pro)insulin-like peptides. The rate of proinsulin (PI) conversion was 2-fold slower in human ␤-cells (t 1/2 ϭ 50 min) than in rat ␤-cells (t 1/2 ϭ 25 min). During the first hour following labeling of newly synthesized proteins, PI represented the main newly formed hormonal peptide in the medium; its release was stimulated 2-fold over the basal level by 20 mmol/L glucose. During the second hour, newly synthesized hormone was mainly released as insulin, with 10-to 20-fold higher rates at 20 mmol/L glucose. Prolonged preculture of the islets at 20 mmol/L glucose did not delay PI conversion, but markedly increased the release of newly formed PI, des 31,32 -PI, and insulin at both low and high glucose levels. Our data demonstrate that 1) the release of PI provides an extracellular index for the hormone biosynthetic activity of human ␤-cells; 2) an acute rise in glucose exerts a stronger amplification of the release of converted hormone than in that of nonconverted hormone; and 3) prolonged exposure to high glucose levels results in an elevated basal release of converted and nonconverted PI; this elevation is not associated with a delay in PI conversion, but is attributed to the hyperactivated state of the human ␤-cell population, which was recently found to be responsible for an elevation in basal rates of hormone synthesis. These in vitro observations on human ␤-cells provide a possible explanation for the altered circulating (pro)insulin levels measured in nondiabetic and noninsulin-dependent diabetic subjects. (J Clin Endocrinol

show abstract

A software package for the evaluation of peak parameters in an analytical signal based on a non-linear regression method

Cited by 24 publications

References 9 publications

Quantitative Study of Concentration Overload, Peak Asymmetry, and Efficiency Loss in Micellar Electrokinetic Chromatography

Quantitative Study of Concentration Overload, Peak Asymmetry, and Efficiency Loss in Micellar Electrokinetic Chromatography

A Micromachined Injection Device for CZE: Application to Correlation CZE

Effect of Glucose on Production and Release of Proinsulin Conversion Products by Cultured Human Islets1

Contact Info

Product

Resources

About