Search results for "calibration [detector]"
showing 10 items of 111 documents
Determination of aluminum at the parts per billion level by solvent extraction and flame atomic emission spectrometry
1991
A new method for the determination of aluminum at the parts per billion level, by N 2 O/ C 2 H 2 flame emission spectrometry with prior solvent extraction with acetylacetone or 8-hydroxyquinoline in 4-methylpentan-2-one, has been performed. The influence of extraction conditions and instrumental parameters on the sensitivity, precision, and dynamic range of the emission calibration curves have been studied. The limit of detection is between 5 and 10 ppb for both ligands, the variation coefficient being 0.2 and 3% at levels of 75 and 25 ppb, respectively. The method has been applied to the determination of Al in water and the results obtained are compared with those found by the standard add…
Quantification of nortriptyline in plasma by HPLC and fluorescence detection
2009
Abstract A simple, sensitive and specific high-performance liquid chromatography method has been developed for the determination of nortriptyline (NT) in plasma samples. The assay involved derivatization with 9H-fluoren-9-ylmethyl chloroformate (Fmoc-Cl) and isocratic reversed-phase (C 18 ) chromatography with fluorescence detection. The developed method required only 100 μl of plasma sample, deproteinized and derivatized in one step. Calibration curves were lineal over the concentration range of 5–5000 ng/ml. The derivatization reaction was performed at room temperature in 20 min and the obtained NT derivative was stable for at least 48 h at room temperature. The within-day and between-day…
A Fully Automated Assembly Using Solenoid Valves for the Photodegradation and Chemiluminometric Determination of the Herbicide Chlorsulfuron
2005
Abstract This paper presents a new photochemiluminescent system for the determination of chlorsulfuron in water samples. The light from a low‐pressure mercury lamp is used as a clean, reproducible, and inexpensive “reagent” for the derivation of the pesticide, performed in glycine buffer at pH 9.5. Then, the photo‐products from irradiation are oxidized by permanganate in sulfuric acid solution. The oxidation reaction was favored by using high temperatures. A comparative study and discussion about the use of polyphosphoric acid instead of sulfuric acid in the oxidation reaction is also presented. The use of solenoid valves allows for the easy, complete automation of the process with low samp…
FI-on line photochemical reaction for direct chemiluminescence determination of photodegradated chloramphenicol.
2002
Abstract A new, simple, clean and selective flow injection strategy based on the tandem photochemical reaction-chemiluminescence detection was applied to the determination of chloramphenicol. The determination is based on the on-line photodegradation of the drug in a glycine buffer at pH 8.8 by using a photoreactor consisting of 697 cm×0.5 mm PTFE tubing helically coiled around an 8 W low-pressure mercury lamp. Photodegradated chloramphenicol is detected by direct chemiluminescence of resulting photo-fragments and their subsequent reaction with potassium permanganate in sulfuric acid medium as oxidant. The method allows the chemiluminescence determination of compounds which do not exhibit n…
Identification of unknown pesticides in fruits using ultra-performance liquid chromatography–quadrupole time-of-flight mass spectrometry
2007
Abstract Ultra-high-performance liquid chromatography–quadrupole time-of-flight mass spectrometry (UPLC-QqTOF-MS) is an emerging technique offering more rapid and efficient separation, as well as the possibility to obtain accurate mass measurement and tandem mass spectrometry (MS/MS). This paper deals with the use of UPLC-QqTOF-MS to identify the pesticide residues present in complex pear extracts. Carbendazim, imazalil, and ethoxyquin were successfully identified because of the accurate mass determination of their protonated molecule and their major fragments in the product ion mass spectra. A few plastic and latex additives were also found, most of them probably coming from the packaging …
Determination of titanium by adsorption-voltammetry with 2-(5-bromo-2-pyridylazo)-5-(diethylamino)-phenol (5-Br-PADAP)
1990
The 1:1 complex between titanium (IV) and 5-Br-PADAP can be used to determine titanium by adsorption voltammetry at a stationary Hg-electrode. The experimental conditions for the determination are described. The detection limit is 3×10−10 mol/l Ti (0.015 ppb). Calibration curves are linear for solutions containing 4×10−10 to 5×10−8 mol/l Ti(IV) and an enrichment time of 3 min. The influence of foreign ions was investigated. The determination can be carried out in the presence of a 5000-fold excess of iron.
The 4th international comparison on EPR dosimetry with tooth enamel
2011
This paper presents the results of the 4th International Comparison of in vitro electron paramagnetic resonance dosimetry with tooth enamel, where the performance parameters of tooth enamel dosimetry methods were compared among sixteen laboratories from all over the world. The participating laboratories were asked to determine a calibration curve with a set of tooth enamel powder samples provided by the organizers. Nine molar teeth extracted following medical indication from German donors and collected between 1997 and 2007 were prepared and irradiated at the Helmholtz Zentrum Munchen. Five out of six samples were irradiated at 0.1, 0.2, 0.5, 1.0 and 1.5 Gy air kerma; and one unirradiated s…
Methylmercury and inorganic mercury determination in fish by cold vapour generation atomic absorption spectrometry
2000
Abstract Given that organic mercury is more dangerous than the inorganic form and that it is converted into methylmercury by biological methylation, we have studied and optimized a simple method for measuring both organic and inorganic mercury contents in fish, using a spectroscopic vapour generation technique, with a sequential reduction of the digested sample with stannous chloride and sodium tetrahydroborate. Prior to applying the method the sample was subjected to alkaline wet digestion. Due to the matrix interferences calibration curves with matrix addition were needed for mercury determinations. The analytical parameters of the method were: linearity from 10 to 200 ng of Hg in the red…
Flow injection biamperometric determination of chloramine-T in environmental, pharmaceutical and veterinary samples
2000
Abstract A flow injection assembly for the determination of chloramine-T is proposed. The sample (213 μl) is inserted into the carrier, de-ionized water flowing at 4.1 ml min−1. This carrier merges with a mixture of potassium iodide and sulphuric acid, and the resulting solution flows to the flow cell through a reactor 66 cm long. The chloramine-T oxidises the iodide to tri-iodide. The resulting iodide/iodine ratio is biamperometrically tested. The calibration graph is linear up to 65 μg ml−1 chloramine-T; the limit of detection is 0.5 μg ml−1; the relative standard deviation (r.s.d) of the calibration slope is 2.8% for a series of eight independent calibrations. The r.s.d. of a series of 7…
Determination of sertraline in rat plasma by HPLC and fluorescence detection and its application toin vivopharmacokinetic studies
2012
A simple, rapid, and sensitive HPLC method based on 9H-fluoren-9-ylmethyl chloroformate derivatization for the quantification of sertraline in rat plasma has been developed, requiring a plasma sample of only 0.1 mL, which was deproteinized and derivatized for 5 min in two single steps. The obtained derivative was stable at room temperature and was determined by HPLC using a fluorescence detector. The analytical column was a C(18) column and the mobile phase was acetonitrile and water (80:20, v/v). Calibration curves were linear in the range of 10-500 ng/mL. The limit of detection was approximately 3 ng/mL, and the lower limit of quantification was established at 10 ng/mL. The bias of the me…