Calibration curve

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

Qualitative and Quantitative Analysis of CO2 and CH4 Dissolved in Water and Seawater Using Laser Raman Spectroscopy

Abstract: Laboratory experiments have been performed using laser Raman spectroscopy to analyze carbon dioxide (CO2) and methane (CH4) dissolved in water and seawater. Dissolved CO2 is characterized by bands at ∼1275 and 1382 Δcm−1. Dissolved CH4 is characterized by a dominant band at ∼2911 Δcm−1. The laboratory instrumentation used for this work is equivalent to the sea-going Raman instrument, DORISS (Deep Ocean Raman In Situ Spectrometer). Limits of quantification and calibration curves were determined for each species. The limits of quantification are ∼10 mM for CO2 and ∼4 mM for CH4. A ratio technique is used to obtain quantitative information from Raman spectra: the gas bands are referenced to the O–H stretching band of water. The calibration curves relating band height ratios to gas concentration are linear and valid for a range of temperatures, pressures, and salinities. Current instrumentation is capable of measuring the highest dissolved gas concentration observed in end-member hydrothermal fluids. Further development work is needed to improve sensitivity and optimize operational configurations.

Determination of morphine in water immiscible process streams using sequential injection analysis coupled with acidic permanganate chemiluminescence detection

Abstract: A procedure for the determination of morphine in non-aqueous, water immiscible, process streams by sequential injection analysis is presented. Detection was based upon the chemiluminescence reaction of morphine with acidic potassium permanganate in the presence of sodium polyphosphate, which was carried out in a heterogeneous reaction environment. The calibration graph (range 0.005–0.12% m/v) was non-linear, with a polynomial equation of best fit of y = –384x2 + 139x – 4.84 (R2 = 0.9990), where y represents the singal (mV) and x represents the morphine concentration (% m/v), and was analytically useful over the range 0.01–0.1% m/v. Precision (as measured by relative standard deviation) was 6.0% for 10 replicate analyses of a non-aqueous morphine standard (0.075% m/v).Methyltriphenylphosphonium permanganate was investigated as an alternative chemiluminescent reagent and was found to deliver a similar analytical performance to potassium permanganate. Sequential injection analysis coupled with chemiluminescence detection afforded results for the determination of morphine in non-aqueous process samples which were in good agreement with those obtained using a standard liquid chromatographic method, with an analytical throughput in excess of 120 h–1.