Search results for "Relative standard deviation"
showing 10 items of 39 documents
Green methodology for quality control of elemental content of infant milk powder
2019
Abstract A green methodology for the direct determination of elemental content in infant milk powder samples from 0 to 3 years was developed. A portable energy dispersive X-ray fluorescence (ED-XRF) tool has been used as a direct method for the quantification of five essential elements (Ca, K, Fe, Cu and Zn). For analysis pellets from 0.8 g of each sample weight were made and analyzed. Due to the high dependence of the ED-XRF signal with the sample matrix, external calibrations using cocoa powder diluted with glucose were performed. Infant milk samples were diluted with lactose and the signals were interpolated in the external calibrations. Concentrations obtained by ED-XRF were compared wi…
Effect of cooking on oxalate content of pulses using an enzymatic procedure.
2003
An enzymatic method proposed for the determination of oxalate in urine is adapted for the estimation of soluble oxalate content in beans, chickpeas and lentils. Oxalates were extracted in water by refluxing for 2 h. The method is based on the oxidation of oxalate by the oxidase and the determination of the resulting hydrogen peroxide, which in presence of peroxidase, 3-methyl-2 benzotiazinolone and 3-dimethylamino benzoic, gives an indamine compound with an absorption maximum at 590 nm. The linearity (from 0.015 to 0.6 mM) of the method is adequate to the analysis of oxalate contents in pulses, and the inter-day precision of the method expressed as relative standard deviation was good (3.01…
Spectrophotometric determination of promazine with an oxidative column in FIA manifolds
1992
Abstract A simple flow-injection spectrophotometric method for the determination of promazine is described. The two proposed procedures are based on the oxidation of analyte with a manganese dioxide column. Concentrations of promazine in the ranges 2–20 and 1–6 are determined with a relative standard deviation of 1.0%. The injection rates are 62 and 80 samples h −1 , respectively. The influence of foreign species and the determination of promazine in a pharmaceutical formulation are also reported.
Flow-injection spectrofluorimetric determination of paracetamol
1990
Abstract A flow-injection spectrofluorimetric determination of paracetamol is reported, based on the oxidation of the analyte with potassium hexacyanoferrate(III) immobilized on an anion-exchange resin, the fluorescence being enhanced with N,N′-dimethylformamide. Concentrations of paracetamol in the range 0.04–17.60 mg l−1 are determined with a relative standard deviation of 1.5%. The injection rate is 25 samples h−1. The influence of foreign species and the determination of paracetamol in several pharamaceutical formulations are also reported.
Immobilization of reagents by polymeric materials. Determination of metamizol
1992
Abstract A method for immobilization of inorganic reagents, based on the dispersion of the reagent into an unsaturated polyester solution is applied to immobilization of lead dioxide. The obtained solid is of application in a flow-injection manifold for indirect atomic absorption determination of metamizol in pharmaceutical formulations. The procedure gives a linear calibration graph up to 6 ppm of metamizol with a relative standard deviation of 1.6% (3.0 mg/l) and a sample throughput of 72 hr−1.
Determination of trichothecenes in chicken liver using gas chromatography coupled with triple-quadrupole mass spectrometry
2018
Abstract Chicken meat and edible offal are included in a wide number of preparations in the worldwide cuisine. Among the offal, the liver is one of the most consumed in some countries like Egypt since it is rich in proteins and is an economical source of many essential nutrients for humans. Mycotoxins, secondary toxic metabolites produced by fungi, have the potential to enter human food chain not only with cereal consumption but also through edible tissues from animals fed with mycotoxin-contaminated feed. Accordingly, a rapid method for the determination of eight trichothecenes in chicken liver was developed based on a quick, easy, cheap, effective, rugged and safe (QuEChERS) extraction an…
Target analysis of primary aromatic amines combined with a comprehensive screening of migrating substances in kitchen utensils by liquid chromatograp…
2015
An analytical strategy including both the quantitative target analysis of 8 regulated primary aromatic amines (PAAs), as well as a comprehensive post-run target screening of 77 migrating substances, was developed for nylon utensils, using liquid chromatography-orbitrap-high resolution mass spectrometry (LC-HRMS) operating in full scan mode. The accurate mass data were acquired with a resolving power of 50,000 FWHM (scan speed, 2 Hz), and by alternating two acquisition events, ESI+ with and without fragmentation. The target method was validated after statistical optimization of the main ionization and fragmentation parameters. The quantitative method presented appropriate performance to be u…
FIA-Chemiluminescence Determination of Acridine Yellow
2003
Abstract The direct determination of yellow acridine is performed by a FIA assembly on the basis of the oxidation of the acridine. The acridine solution is injected into a pure water stream. This solution merges with the oxidant solution (KMnO4 in sulfuric acid medium) and the resulting chemiluminescence allows the method to be applied over the range 0.01–100 mg L−1 of acridine with a correlation coefficient of 0.9997. The relative standard deviation (%) is 1.6 and the sample throughput 60 h−1. The influence of foreign substances is also tested. The new method is applied to the determination of yellow acridine in waste waters.
Comparison of spectrophotometric and HPLC methods for determining sialic acid in infant formulas
2011
Abstract Two methods for determining sialic acid in infant formulas – spectrophotometry and HPLC with fluorescence detection – have been optimised and validated, the first one allows to determine total sialic acid while the second allows to differentiate the two main forms of sialic acid (N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc)). A common sample preparation procedure (hydrolysis and purification) for both methods has been proposed. The linearity (from 6 to 150 μg of total sialic acid in the assay for spectrophotometry, and from 12.5 to 250 ng and 1 to 5 ng of Neu5Ac and Neu5Gc, respectively, for HPLC) is adequate. The detection and quantification limits (0.29…
Determination of tea tree oil terpenes by headspace gas chromatography mass spectrometry
2016
An alternative procedure was developed for determining quality control of terpenes in tea tree oil commercial samples. The method is based on static headspace gas chromatography mass spectrometry measurements. Absolute limits of detection ranged from 1 ng for p-cymene to 71 ng for terpinen-4-ol. The accuracy of the developed methodology was evaluated by comparing the obtained eucalyptol and terpinen-4-ol concentrations with those provided for a certified sample and by comparing the developed procedure with literature tea tree oil analysis methodology. In the same way, spiked commercial samples provided recovery values ranging between 94% and 100% for all the target analytes with relative st…