0000000000117614
AUTHOR
S. Sagrado Vives
Continuous-flow tristimulus colorimetry: a new approach for gradient scanning techniques
Abstract A flow-injection gradient scanning technique for colour evaluation by means of tristimulus colorimetry is described. Equipment and data acquisition requirements are discussed. The program CHROMA.FIA data the treatment and comparative chromatic analysis is presented. The chemical and flow conditions were optimized. Comparative studies using metallochromic indicators with both the flow-injection and the conventional batch procedures were made. The continuous-flow procedure provides good results and is more than fifteen times faster than the manual titrimetric procedure.
Some observations on the automation by flow injection analysis of the spectrophotometric determination of amino acids and proteins witho-phthalaldehyde
Automation by flow injection analysis with Spectrophotometric detection of the determination of total amino acids and proteins witho-phthalaldehyde is not straightforward. The use of spectrophotometry, instead of spectrofluorimetry, and of N-acetyl-L-cysteine, instead of the conventional mercaptoethanol is advantageous because of the lower variability of absorptivities with respect to fluorescence yields, and the larger stability of the derivatives. Under adequate working conditions and with leucine as reference, the procedure can be used for the evaluation of total amino acids. A similar procedure is proposed for the analysis of proteins in a sample. Limits of detection are ≈ 1 × 10−5M for…
Fluorimetric determination of captopril by flow injection analysis
A flow injection analysis procedure is proposed for the determination of captopril. The sample solution was directly injected into the carrier-reagent stream which was prepared by a solution of ceric ions in 0.25 M sulfuric acid. The procedure is based on the fluorimetric monitoring of the formed Ce(III). Chemical, FIA, and instrumental parameters were optimized and the procedure is applied to the captopril determination in pharmaceutical formulations with competitive precision and adequate accuracy.
Fluorometric determination of diphenhydramine by flow-injection analysis
A sensitive, rapid and simple flow injection procedure for the determination of diphenhydramine has been designed based on a fluorometric approach. An aqueous solution of diphenhydramine is injected into a carrierreagent stream containing Ce(IV) in dilute sulphuric acid and the fluorescence intensity of the Ce(III) produced is monitored. Chemical, FIA and instrumental variables were optimized. Analytical features of the method are: linear range 0.2–2 ppm, precision 0.7%, sample throughput 80/h. The influence of some foreign substances which can be found in typical pharmaceutical samples containing diphenhydramine was also investigated. The diphenhydramine content of a pharmaceutical prepara…