Calibration curve

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

Chemometric protocol to validate an analytical method in the presence of corrigible constant and proportional systematic errors

Abstract: A statistical methodology to verify the trueness of an analytical method in the presence of corrigible systematic errors is presented. This protocol enables detection of constant and proportional components of error. By using the data set obtained in the Youden calibration with different sample test portions, the constant component of the error (Youden blank) can be determined. An analysis of covariance was applied to 3 calibration curves established with standard solutions and with standard additions to 2 different sample test portions. The slopes were compared, and the presence of any matrix-analyte interaction was detected. A method for removing the numerical components of systematic errors is proposed: a calculation procedure to obtain a correct analytical result and a statistical test to verify the correctness of analyte contents obtained from different calibrations. For demonstration purposes, the protocol was applied to spectrofluorometric determination of oxalates in spinach leaves.

Direct J-R Curve Analysis: A Guide to the Methodology

Abstract: A direct method for evaluating J-R curves from load displacement data is proposed. This method eliminates a need for automatic crack length monitoring equipment. The method uses the geometric normalization suggested by Ernst for deeply cracked bend specimens to develop calibration curves which relate load, displacement, and crack length. Given two of these parameters, the third can be determined from the calibration curves. These curves are developed by assuming a functional form with unknown constants and evaluating the unknowns at calibration points in the test. This method was previously proposed using a power law functional form. In this paper a more general functional form is proposed which combines a power law and straight line. The method is studied for a variety of materials and specimen sizes. From the results a recommendation is made on how to generally apply the method.

Manual sampling and tank size effects on the calibration curve of plot sediment storage tanks

Abstract: In many experimental soil erosion plots, runoff is collected and carried by a conveyance system to a sequence of storage tanks. If the soil loss is measured by collecting, after mixing, samples of the stored suspension, then a calibration curve between the actual mean concentration (C) and the measured concentration (Cm) in the storage tank occurs. The aim of this article was to evaluate experimentally the factors affecting the relationship between C and Cm. For a sandy loam soil, the replicated measurements of Cm (20 samples) for two values of the actual concentration (C = 5 and 25 g/L) showed that the variability of the measurements of Cm is low and confirmed the reliability of a calibration curve obtained by a single series of runs. Results from experiments carried out with a clay soil to compare the calibration curves obtained by four field workers suggested that the maximum uncertainty in the soil loss measurement due to the choice of the calibration curve should not exceed 100% of the true value. Moreover, the slope of the calibration curve was independent of both the water level in the tank and the field worker. Finally, a comparison among the calibration curves of a prototype tank and some model tanks was carried out for both a sandy loam and a clay soil in order to establish a scaled-up relationship among tanks of different size. Soil-specific and theoretically based scaled-up relationships were deduced.