An inexpensive, portable and microcontrolled near infrared LED-photometer for screening analysis of gasoline.
A microcontrolled, portable and inexpensive photometer is proposed. It uses a near infrared light emitting diode (NIR LED) as radiation source, a PbSe photoresistor as infrared detector and a programmable interrupt controller (PIC) microcontroller as control unit. The detector system presents a thermoresistor and a thermoelectric cooling to control the detector temperature and keep the noise at low levels. The microcontroller incorporated total autonomy on the proposed photometer. As its components are inexpensive and of easy acquisition, the proposed NIR LED-photometer is an economical alternative for chemical analyses in small routine, research and/or teaching laboratories. By being portable and microcontrolled, it also allows carrying out field chemical analyses. The instrument was successfully applied on the screening analysis to verify adulteration in gasoline samples.
Gaião
Edvaldo da Nóbrega
Eda N
Universidade Federal da Paraíba, CCEN, Departamento de Química, Caixa Postal 5093, 58051-970 João Pessoa, PB, Brazil.
dos Santos
Sérgio Ricardo Bezerra
SR
dos Santos
Vagner Bezerra
VB
do Nascimento
Elaine Cristina Lima
EC
Lima
Renato Sousa
RS
de Araújo
Mário César Ugulino
MC
D011211:Electric Power Supplies; D005742:Gasoline / Q000032:analysis* / Q000592:standards*; D007259:Infrared Rays; D008832:Microchemistry; D010783:Photometry / Q000191:economics / Q000295:instrumentation / Q000379:methods; D012666:Semiconductors
D005742:Gasoline