Calibration curve

About: Calibration curve is a research topic. Over the lifetime, 6552 publications have been published within this topic receiving 95128 citations.

Apparatus and breathing bag for spectrometrically measuring isotopic gas

Abstract: A correction curve (FIG. 19) is prepared by plotting 12 CO 2 concentrations and 13 CO 2 / 12 CO 2 concentration ratios which are determined on the basis of a calibration curve and 13 CO 2 and 12 CO 2 absorbances of gaseous samples having the same 13 CO 2 / 12 CO 2 concentration ratio but known different 12 CO 2 concentrations. A gaseous test sample containing 13 CO 2 and 12 CO 2 as component gases is introduced into a cell, and spectrometrically measured. A 12 CO 2 concentration of the gaseous test sample is determined by way of the spectrometric measurement. A concentration ratio correction value is obtained on the basis of the correction curve and the 12 CO 2 concentration of the gaseous test sample thus determined. A measured 13 CO 2 / 12 CO 2 concentration ratio is divided by the concentration ratio correction value thus obtained for correction of the 13 CO 2 / 12 CO 2 concentration ratio. Thus, the measurement accuracy of the concentration ratios of the component gases can be improved. A breath sampling bag and gas measuring system is also disclosed where each is configured such that breath inlets of the gas measuring apparatus are prevented from being respectively connected to the wrong breath introduction pipes of the breath sampling bag.

Determination of lead in wine by hydride generation atomic fluorescence spectrometry in the presence of hexacyanoferrate(III)

Abstract: A rapid, accurate, and precise method is described for the determination of Pb in wine using continuous-flow hydride generation atomic fluorescence spectrometry (CF-HGAFS). Sample pretreatment consists of ten-fold dilution of wine followed by direct plumbane generation in the presence of 0.1 mol L−1 HCl and 1% m/v K3[Fe(CN)6] with 1% m/v NaBH4 as reducing agent. An aqueous standard calibration curve is recommended for Pb quantification in wine sample. The method provides a limit of detection and a limit of quantification of 0.3 μg L−1 and 1 μg L−1, respectively. The relative standard deviation varies between 2–6% (within-run) and 4–11% (between-run) at 3–30 μg L−1 Pb levels in wine. Good agreement has been demonstrated between results obtained by CF-HGAFS and direct electrothermal atomic absorption spectrometry in analyses of red and white wines within the concentration range of 9.2–25.8 μg L−1 Pb.

Stable isotope measurement method and apparatus by spectroscopy

Abstract: In accordance with the present invention, a test gas sample containing carbon dioxide 13CO2 as a component gas is introduced into a cell, then the absorbance of light transmitted therethrough at a wavelength suitable for the component gas 13CO2 is determined, and the concentration of the component gas is determined on the basis of a calibration curve prepared through measurement on test gas samples each containing the component gas in a known concentration. Further, the concentration of water vapor contained in the test gas sample is measured, and the concentration of the component gas in the test gas sample is corrected in accordance with the measured water vapor concentration on the basis of a correction curve prepared through measurement on the test gas samples each containing water vapor in a known concentration. With the spectrometry, the concentration ratio of the component gas can precisely be determined and corrected by measuring the moisture content in the test gas sample.

Determination of copper by flame atomic absorption spectrometry after solid-phase extraction

Abstract: A new solid‐phase extraction method was developed for trace analysis of copper. The method is based on the retention of copper as methylthymol blue complex on naphthalene–methyltrioctyl ammonium chloride adsorbent in a column. The adsorbed metal complex was eluted from the column with nitric acid, and its copper content was determined by flame atomic absorption spectrometry. The effect of different variables such as pH, reagent concentration, solution flow rate, and interfering ions on the recovery of the analyte was investigated. The calibration graph was linear in the range 5–200 ng mL−1 of copper in the initial solution with r=0.9976. The 3Sb detection limit was 2 ng mL−1, and the relative standard deviation for eight replicate measurements of 25 and 100 ng mL−1 of copper was 4.2% and 1.7%, respectively. The method was applied to the determination of copper in river and sewage water samples.