Development of a multicommuted flow analysis procedure for simultaneous determination of sulfate and chloride in petroleum coke employing a homemade syringe pump and a LED-based photometer

Abstract

Diagram of the flow system and its working pattern.

A Sensitive Photometric Procedure for Cobalt Determination in Water Employing a Compact Multicommuted Flow Analysis System

“…The setup comprised the apparatus described as follows: one microcomputer, furnished with a PLC711S interface card (Advantech Corp.) and control software written in Quick BASIC 4.5; two solenoid mini-pumps 120SP1220, one 120SP1240 (BioChem Valve Inc.) and three three-way solenoid valves HP161 T031 (NResearch Inc.), which were used to assemble the flow analysis module; one photodetector 0PT301 (Texas Instruments), one high-bright 5 mm blue LED ( max ¼ 425 nm, luminous intensity of 5000 mcd) with an emission angle of & 25 , and one flow cell with an optical pathlength of 100 mm, used to construct the photometer; one digital interface to drive the solenoid valves and mini-pumps, similar to that described elsewhere; 32 regulated power supplies, one -12.0 V and þ12.0 V with an electric current intensity of 0.5 A used to feed the photometer and another one of þ12 V and an electric current intensity of 2 A used to feed the solenoid valves and solenoid mini-pumps; and two three-way flow line joint devices machined in an acrylic and polyethylene tube (200 cm long, 0.8 mm inner diameter) to construct reaction coil and flow lines.…”

Automatic Procedure for Spectrophotometric Determination of Hydroquinone Employing Multicommutation Flow in Analysis System

“…Um microcomputador equipado com uma interface PCL711S (Advantech corp. OH, USA), foi utilizado para gerar os sinais de controle das válvulas solenoide, os quais foram enviados para uma interface de potência baseada no circuito integrado ULN 2803. 16 Esses sinais são gerados com uma diferença de potencial de 5 V, e a interface de potência permite o acionamento das válvulas solenoide alimentadas com uma diferença de potencial de 12 V. O espectrofotômetro FEMTO 700 Plus (São Paulo, Brasil), equipado com cela de fluxo de 80 µL e caminho óptico de 10 mm, foi acoplado ao computador através da interface serial RS 232C, permitindo a realização da aquisição de dados. O controle de todo o sistema e a aquisição dos dados foram executados, usando um programa computacional escrito em linguagem Quick BASIC 4.5.…”

“…6,14 O presente trabalho compreende o desenvolvimento e a aplicação de um procedimento espectrofotométrico para a determinação de HQ em formulações farmacêuticas (Gel), empregando o processo de multicomutação em análise em fluxo (MCFA). 15,16 O procedimento é baseado na reação de oxidação da molécula de HQ com ferro (III) em meio ácido e posterior reação do ferro (II) gerado com 1,10-fenantrolina, formando um complexo que é detectado em 510 nm. 7 Atualmente, é consenso de que os procedimentos analíticos devem ser ambientalmente amigáveis, e para isso devem atender as diretrizes preconizadas pelo conceito de química verde (GAC -Green Analytical Chemistry).…”

A Highly Sensitive Multicommuted Flow Analysis Procedure for Photometric Determination of Molybdenum in Plant Materials without a Solvent Extraction Step

“…Spectrophotometry technique allows the use of cost-effective instrumentation, such as homemade photometers, assembled using light emitting diode (LED) and photodiode [16, 17]. However, the low sensitivity of this procedure presents a drawback, which is often overcome by including a solvent extraction step [7].…”

“…Among the above detection techniques, spectrophotometry presents several advantages, including its flexibility to be automated using flow injection analysis (FIA) [ 12 , 13 ], methodology that has been widely used to develop analytical procedures [ 14 , 15 ]. Spectrophotometry technique allows the use of cost-effective instrumentation, such as homemade photometers, assembled using light emitting diode (LED) and photodiode [ 16 , 17 ]. However, the low sensitivity of this procedure presents a drawback, which is often overcome by including a solvent extraction step [ 7 ].…”