Search results for "INJECTION"
showing 10 items of 920 documents
Spectrophotometric determination of promethazine by flow injection analysis and oxidation by CeIV
1992
A flow injection analysis (FIA) procedure is proposed for the determination of promethazine. The sample solution is directly injected into the carrier-reagent stream which comprises a solution of ceric ions in a sulphuric acid medium. The absorbance at 514 nm from the red colour developed by the oxidation of promethazine is measured. Effects of foreign substances have been investigated and the procedure has been applied to the determination of promethazine in a pharmaceutical formulation (tablets).
Implementation of multicommutation principle with flow-through multioptosensors
2005
Abstract For the first time, the combination of multicommutation concept with flow-through multioptosensors is exploited and a biparameter multicommutated UV sensor is developed. A very easy-operated and automated sensing device is proposed here and demonstrated to be useful in the routine analysis by applying it to the determination of two widely used pharmaceuticals chosen as model analytes: salicylamide and caffeine. The particulated solid phase used performs two functions: (a) states selectivity conditions by itself in the flow cell and (b) provides appropriate separation of the analytes in the on-line precolumn, thus making possible the sequential arrival of the analytes to the detecti…
Flow injection biamperometric determination of metronidazole with on-line photodegradation
1999
Abstract The determination of metronidazole is performed in a flow injection assembly, provided with a 40 W low pressure mercury lamp and a home-made biamperometric flow-cell furnished with two platinum electrodes polarized at 100 mV. The sample solution after being irradiated is inserted into a pure water stream. It then merges with an in situ mixed solution containing potassium iodide in sulphuric acid. The calibration graph was linear over the range 0.2–8.0 mg l −1 metronidazole; the 3 σ limit of detection was 0.008 mg l −1 ; the relative standard deviation was 0.6% (for 4 mg l −1 n = 13) and the sample throughput 50 h −1 . The influence of foreign compounds is slight and the method is …
Fourier transform infrared spectrometric strategies for the determination of Buprofezin in pesticide formulations
2002
Abstract Two different strategies for Buprofezin determination, an off-line extraction and stopped-flow determination and an automated procedure, based on the on-line extraction of Buprofezin samples with chloroform and flowing action analysis–fourier transform infrared (FIA–FT-IR) spectrometric measurement of the extracts, have been developed. For the treatment of the off-line extraction mode, data a three-factor partial least squares (PLSs) calibration was developed, using the region from 1465.7 to 1342.3 cm−1 with a single point baseline defined at 2051.9 cm−1 and based on the use of chloroform solutions of Buprofezin. The method provides a R.S.D. On the other hand, the recommended FIA m…
Direct flow injection chemiluminescence determination of salicylamide
1999
Abstract A new direct flow injection chemiluminescence method is proposed for the determination of salicylamide, based upon the oxidation of the drug by potassium permanganate in dilute sulphuric acid. The calibration graph is linear over the range 20 ng ml−1 (30 limit of detection)–8 μg ml−1 salicylamide, with a relative standard deviation (n=50, 0.5 μg ml−1) of 1.7%. The average sample insertion rate is 142 h−1. The influence of relevant foreign compounds is found to be relatively slight. The method is applied to the determination of salicylamide in a pharmaceutical formulation and human urine.
Fourier transform infrared spectrometric determination of Malathion in pesticide formulations
2004
Abstract An environmentally friendly methodology has been developed for quality control analysis of emulsifiable concentrate pesticide formulations containing Malathion as active ingredient, using flow injection analysis (FIA)–Fourier transform infrared (FTIR) spectrometry. Five microlitres samples were directly injected into a 3 ml closed FIA manifold, in which 2 ml of CHCl 3 was re-circulated at 1.96 ml min −1 . After homogenisation and sample measurement, 2 μl volumes of a Malathion standard were injected, taking absorbance measurements after each injection. Peak height of the chemigrams, established from peak area values between 1027 and 1017 cm −1 , corrected with a baseline fixed from…
Multipumping Nitrite Determination in Exhaled Breath Condensate
2006
Abstract A flow system based on multicommutation is proposed for the rapid, clean, and inexpensive determination of nitrites in small volumes of breath condensates. The procedure exploits the colorimetric detection of nitrite with the Griess reagent [0.03% naphthylethylene diamine dihydrochloride (NED), 0.5% sulpfhanilamide, and 3.0% phosphoric acid] in acidic medium at 540 nm correcting the variations of the baseline with measurements at 424 nm. The flow system was designed with a set of solenoid micropumps to minimize sample and reagent consumption and waste generation. The detection limit was estimated as 3.8 ng mL−1 (99.7% confidence level) with a linear response ranging up to 500 ng mL…
A multicommuted stop-flow system employing LEDs-based photometer for the sequential determination of anionic and cationic surfactants in water
2006
It has been developed an automatic stop-flow procedure for sequential photometric determination of anionic and cationic surfactants in a same sample of water. The flow system was based on multicommutation process that was designed employing two solenoid micro-pumps and six solenoid pinch valves, which under microcomputer control carry out fluid propelling and reagent solutions handling. A homemade photometer using a photodiode as detector and two light emitting diodes (LEDs) with emission at 470 nm (blue) and 650 nm (red) as radiation sources, which was tailored to allow the determination of anionic and cationic surfactants in waters. The procedure for anionic surfactant determination was b…
Determination of cyanide by a flow injection analysis-atomic absorption spectrometric method
1999
A new flow injection analysis (FIA) procedure is proposed for the indirect atomic absorption spectrometric determination of cyanide. The FIA manifold is based on the insertion of the sample into a distilled water carrier, then the sample flows through a solid-phase reactor filled with silver iodide entrapped in polymeric resin beads. The calibration graph is linear over the range 0.2-6.0 mg l-1 of cyanide (correlation coefficient 0.9974), the detection limit is 0.1 mg l-1, the sample throughput is 193 h-1 and the RSD is 0.8%. The method is simple, quick and more selective than other published FIA procedures. The reproducibility obtained by using different solid-phase reactors and solutions …
Flow injection spectrophotometric determination of lead using 1,5-diphenylthiocarbazone in aqueous micellar
2009
A simple flow injection colorimetric procedure for determining lead was established. It is based on the reaction of lead in sulfuric acid with 1,5-diphenylthiocarbazone and sodium dodecyl sulfate, resulting in an intense red-blue complex with a suitable absorption at 500 nm. A standard or sample solution was injected into the sulfuric acid stream (flow rate of 2.0 ml min(-1)), which was then merged with sodium dodecyl sulfate stream (flow rate of 2.0 ml min(-1)) and 1,5-diphenylthiocarbazone stream (flow rate of 1.5 ml min(-1)). Optimum conditions for determining lead were investigated by univariate method. Under the optimum conditions, a linear calibration graph was obtained over the range…