Calibration curve

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

Calibration Effects for Laser- Induced Breakdown Spectroscopy of Gaseous Sample Streams: Analyte Response of Gas-Phase Species versus Solid-Phase Species

Abstract: The effects of analyte phase on the calibration response for laser-induced breakdown spectroscopy is investigated for a range of carbon species. Significant differences in the atomic emission signal from carbon were observed when comparing calibration streams of gas-phase and submicrometer-sized solid-phase carbon species. The resulting calibration curve slopes varied by a factor of 8 over a comparable range of atomic carbon concentrations for five different analyte sources, while the plasma electron density and temperature remained essentially constant. The current findings challenge a widely held assumption that complete dissociation of constituent species within a highly energetic laser-induced plasma results in independence of the analyte atomic emission signal on the analyte source. A physical model of the plasma−analyte interaction is proposed that provides a framework to account for the observed dependence on the physical state of the analyte.

Protocol for production of matrix-matched brain tissue standards for imaging by laser ablation-inductively coupled plasma-mass spectrometry

Abstract: Calibration with matrix-matched standards remains the most practical means for producing quantitative images of trace metal distribution in tissue sections by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). A general guide for producing matrix-matched standards for assay of trace metals in brain tissue is presented. Cortical tissue was taken from pooled sheep brains and spiked with varying approximate concentrations of standard solutions of Co, Cu, Fe, Mg, Mn, Sr, Se and Zn. The tissue was homogenised and the total analyte amount accurately determined by solution nebulisation ICP-MS. The analytical figures of merit for LA-ICP-MS imaging were determined from these tissue standards cryosectioned at 30 μm. Repeated 8-point calibration curves were reproducibly linear, with correlation coefficients ranging from 0.9874 (Mg) to 0.9991 (Sr). Limits of analysis were suitable for quantifying most analytes in a sample mouse brain, with the exception of Co and Se.

Correction of Polychromatic Luminescence Signals for Inner-Filter Effects

Abstract: Fluorescence (FL) and absorbance (ABS) data are acquired simultaneously with a multiple detector spectrometer. The measured ABS is utilized in mathematical equations for automatic correction of fluorescence signals for attenuation (inner-filter effects) caused by significant absorption of the excitation or emission radiation by the fluorophore or other species. Correction equations are presented which apply to situations in which the excitation or emission beam cannot be considered monochromatic, for collection geometries involving optical fibers, and for chemiluminescence measurements. The correction scheme was tested with quinine sulfate (QS) as the analyte in the absence and presence of other chromophores (gentisic acid and methyl red). Even when conditions are such that the FL signal is attenuated by a factor of 5, the correction scheme is accurate to 2% or better. These corrections extend the linear range of the QS calibration curve by a factor of over 100, and they can improve the accuracy up to a factor of ten in cases for which polychromatic effects are important.