Topic
Calibration curve
About: Calibration curve is a research topic. Over the lifetime, 6552 publications have been published within this topic receiving 95128 citations.
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TL;DR: In this article, the fishpole balance developed by Lowry was modified by using commercially available quartz fibers, by an improved sample-loading system, and by supplying the microscope with a vertical fine adjustment.
46 citations
TL;DR: In this article, a critical evaluation of the filter paper method is presented, which evaluates wetting and drying filter paper suction calibration and total and matric soil suction measurement techniques using the filter papers method.
Abstract: In this paper, a critical evaluation of the filter paper method is presented. The paper evaluates wetting and drying filter paper suction calibration and total and matric soil suction measurement techniques using the filter paper method. Calibration of the method was investigated by evaluating the processes of wetting and drying the filter papers through vapor transfer and of wetting and drying the filter papers through fluid transfer. Recent research shows that different calibration curves result from two different experimental measurement programs (vapor transfer, no contact method and fluid transfer, contact method) for total and matric components of suction. In this study, a filter paper wetting curve was constructed using osmotic suction potentials of sodium chloride (NaCl), ammonium chloride (NH4Cl), calcium chloride (CaCl2), and sodium sulfate (Na2SO4) salt solutions and Schleicher & Schuell No. 589-WH filter papers. Equilibrium time and temperature were two weeks and 25°C with ±0.1°C accuracy, respectively. The adopted laboratory testing protocol shows that suction measurements as low as 50 kPa can be made reliably using the wetting calibration curve obtained in this research study. The calibration curves obtained from the processes of drying the filter papers through vapor transfer (from salt solutions) and drying and wetting the filter papers through fluid transfer (pressure plate type devices) were evaluated based on recently published literature. Although there is hysteresis between the wetting curve with salt solutions and the drying curve with pressure plates, the marked differences between the curves at very low suction levels may not be explained with hysteresis.
46 citations
TL;DR: In this paper, a calibration curve for high molecular bituminous components by combining the chromaiograms with molecular-weight distributions derived from velocity ultracentrifugation, partly with measured average molecular weights is presented.
Abstract: For the determination of molecular-weight distributions by means of gel-permeation chromatography, one needs a calibration curve which relates molecular weight to elution volume Such a curve has been constructed for high molecular bituminous components by combining the chromaiograms partly with molecular-weight distributions derived from velocity ultracentrifugation, partly with measured average molecular weights It proved possible to calculate the calibration curve for asphaltenes when that for polymers is known Benoit's universal calibration curve, in which the product of molecular weight and limiting viscosity number is used as a measure of the hydrodynamic volume, does not apply for asphaltenes
46 citations
TL;DR: In this article, an optical sensor was designed for the determination of zinc by spectrophotometry, which was made by immobilizing Zincon as an ion pair with methyltrioctylammonium ion on triacetylcellulose membrane.
Abstract: An optical sensor has been designed for the determination of zinc by spectrophotometry. The sensing membrane is made by immobilizing Zincon as an ion pair with methyltrioctylammonium ion on triacetylcellulose membrane. In the present of Zn2+ ions in ammonia/ammonium chloride buffer at pH 9 the color of the membrane changes from purple to blue. The calibration curve was linear in the range of 0.76–30.60 μM of Zn2+ ion with a limit of detection 0.16 μM (10.5 ng ml−1). The response time of the optode was about 10–12 min, depending on the concentration of Zn2+. The sensor can readily be regenerated with hydrochloric acid solution. This optode is stable and could be stored under water for three weeks without reagent leaching. The relative standard deviation for seven replicate measurements of 7.65 and 15.30 μM Zn2+ was 3.09 and 2.82%, respectively. The sensor was successfully applied to the determination of zinc in powdered milk and hair samples.
46 citations
22 May 2001
TL;DR: In this article, a transmittance pulse oximetry system based on near-infrared laser diodes (LD) for monitoring arterial blood hemoglobin oxygen saturation (So 2 ) has been previously reported.
Abstract: A transmittance pulse oximetry system based on near-infrared laser diodes (LD) for monitoring arterial blood hemoglobin oxygen saturation (So 2 ) has been previously reported. In this work we present the results obtained after improvements in the sensor configuration, signal processing algorithm and calibration procedure. The pulse oximetry system also comprises the sensor electronics, and a data acquisition board installed on a handheld personal computer. The two LD chips are mounted on a single metal heat-sink and as photo- detectors are used silicon p-i-n photodiodes with the first amplifier stage situated in their back side. The real time calculation of the parameters related to So 2 is carried out through a numeric separation of the pulsatile and non- pulsatile components of the photoplethysmographic signals for both wavelengths and a non-linear filtering. Patients with respiratory failure conditions were monitored as a part of the calibration procedure in order to cover a wide range of So 2 -values. A calibration curve have been derived through the determination of in vitro arterial So 2 with a significant quantity of experimental points ranging from 60 to almost 100%. The obtained results demonstrate that it is possible to apply the proposed system to monitoring a wide range of oxygen saturation levels.
46 citations