Search results for "Calibration curve"
showing 10 items of 99 documents
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…
Preliminary application of thermoluminescence and single aliquot regeneration method for dose reconstruction in soda lime glass
2013
The research described in this paper shows that the use of the single aliquot regeneration (SAR) method for thermoluminescence (TL) measurements applied to soda lime glasses allows to carry out a retrospective dose evaluation. We have followed a fast and efficient sample preparation procedure which permits measurements without powdering and sieving processes. We have analyzed the TL signal of commercial soda lime watch glass irradiated with 6 Mega Volts (MV) LINAC photons, 10 MeV LINAC electrons and 62 MeV protons. After the initial exposure and following TL reading, the samples are successively irradiated with increasing doses of photons. Therefore, for each sample its calibration curve is…
Flow-injection analysis study of the chemiluminescent behaviour of proflavine and acriflavine
2001
Abstract The chemiluminescent behaviour of the amino acridines like acriflavine, and proflavin is reported. Different strong oxidants (potassium permanganate, cerium(IV), hexacyanoferrate(III), hydrogen peroxide in different media) were tested, and potassium permanganate in sulphuric acid medium was selected. The study of the experimental parameters affecting the oxidation and detection was performed with the aid of a FIA assembly. The calibration graph was applied over the range 0.05–12.0 μg ml −1 of acriflavine (regression coefficient 0.9957, and the calculated relative standard deviation (R.S.D., %) was 0.9; LOD 10 ng ml −1 and the sample throughput 48 h −1 . The study of interfering com…
Determination of Amitriptyline with Bromocresol Purple and Flow Injection Analysis
1990
Abstract The study of some amitriptyline-dye systems was carried out in order to determine the best precipitate for the turbidimetric determination of amitriptyline using FIA. The reagent selected was bromocresol purple. The chemical and FIA variables were optimized. The calibration graph was linear over the concentration range 30.0–200.0 ppm of amitriptyline hydrochloride. Some interfering substances were also investigated.