Calibration curve

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

The british archaeomagnetic calibration curve: an objective treatment

Abstract: This paper examines the limitations and deficiencies of the current archaeomagnetic calibration curve in use in Britain and explores a different approach to its construction, drawing on recent advances in this subject, in particular the use of a weighted moving window method of averaging. The main advantage of this method is shown to be its ability to take into account uncertainties in both the magnetic direction and the archaeological date of data used in the calibration curve, leading to a secular variation curve with an associated error estimate. Hence, when dating a magnetic direction, the uncertainties in the calibration curve can be taken into account, as well as the uncertainties in the magnetic direction to be dated.

Bioimaging of metals in thin mouse brain section by laser ablation inductively coupled plasma mass spectrometry: novel online quantification strategy using aqueous standards

Abstract: A novel solution-based calibration method for quantitative spatial resolved distribution analysis (imaging) of elements in thin biological tissue sections by LA-ICP-MS (laser ablation inductively coupled plasma mass spectrometry) is described. A dual flow of the carrier and nebulizer gas is used to transport the aerosol of the laser ablated solid sample (brain tissue) and that of the nebulized aqueous standard into inductively coupled plasma (ICP) source, respectively. Both aerosols are introduced separately in the injector tube inside a special ICP torch and then mixed in the inductively coupled plasma. Calibration curves were obtained via two different calibration strategies: (i) solution based calibration and (ii) with a set of well characterized homogeneous brain laboratory standards. In the first approach matrix matching is performed by solution nebulization of a series of aqueous standards with defined analyte concentrations and simultaneous laser ablation of brain homogenate followed by nebulization of 2% (v/v) HNO3 and laser ablation of a whole brain slice (line by line). In the second approach of calibration a set of brain homogenates with defined analyte concentrations is analyzed by LA-ICP-MS followed by the imaging of brain tissue under the same experimental conditions (dry plasma). Calibration curves of elements of interest (e.g., Li, Na, Al, K, Ca, Ti, V, Mn, Ni, Co, Cr, Cu, Zn, As, Se, Rb, Sr, Y, Cd, Ba, La, Ce, Nd, Gd, Hg, Pb, Bi and U) were obtained using (i) aqueous standards or (ii) the set of synthetic laboratory standards prepared from a mouse brain homogenate doped with elements at defined concentrations. The ratio of the slope of the calibration curves (obtained by using aqueous standards and solid standards) was applied to correct the differences of sensitivity among ICP-MS and LA-ICP-MS. Quantitative images of Li, Mn, Fe, Cu, Zn and Rb in mouse brain were obtained under wet plasma condition (nebulization of HNO3 solution in parallel with ablation of solid brain sample).

Enhanced performance of ion-selective electrodes in flow injection analysis: non-nernstian response, indirect determination, differential detection and modified reverse flow injection analysis

Abstract: Some general aspects concerning the measuring device, cell design, flow manifold and sensor requirements for the incorporation of ion-selective electrodes (ISEs) in flow injection systems are outlined. The main aim of this paper is to demonstrate how the control of sample dispersion and timing in flow injection analysis (FIA) can be used to attain unique potentialities. The detection limits of ISEs can be decreased, even below the intrinsic solubility of the sensor membrane. The integration of sample processing steps within the manifold improves the reliability of the electrode for reaction products which are unstable or volatile. The series differential detection method is shown to increase the sensitivity (slope of the calibration graph) and to simplify data evaluation. The indirect determination of trace amounts of aluminium with a fluoride ISE can be performed with a simple experimental set-up and high sample throughput. Finally, the modified reverse FIA technique is shown to be a novel method for process analysis, continuous monitoring purposes and high precision calibration.