A comparative study of calibration transfer methods for determination of gasoline quality parameters in three different near infrared spectrometers.
This work presents a comparative study of calibration transfer among three near infrared spectrometers for determination of naphthenes and RON (Research Octane Number) in gasoline. Seven transfer methods are compared: direct standardization (DS), piecewise direct standardization (PDS), orthogonal signal correction (OSC), reverse standardization (RS), piecewise reverse standardization (PRS), slope and bias correction (SBC) and model updating (MU). Two pre-treatment procedures, namely standard normal variate (SNV) and multiplicative scatter correction (MSC), are also investigated. The choice of an appropriate number of transfer samples for each technique, as well as the effect of window size in PDS/PRS and OSC components, are discussed. A broad set of gasoline samples representative of the Northeastern states of Brazil is employed in the investigation. The results show that the use of calibration transfer yields prediction errors comparable to those obtained with complete recalibration of the secondary instrument. Overall, the results point to RS as the best method for the analytical problem under consideration. When storage and/or physical transportation of transfer samples are impractical, MU is more appropriate. The comprehensive investigation carried out in the present work will be of value for practitioners involved in networks of fuel monitoring.
Pereira
Claudete Fernandes
CF
Departamento de Engenharia Química, Universidade Federal de Pernambuco, Recife/PE, Brazil.
Pimentel
Maria Fernanda
MF
Galvão
Roberto Kawakami Harrop
RK
Honorato
Fernanda Araújo
FA
Stragevitch
Luiz
L
Martins
Marcelo Nascimento
MN
D002138:Calibration; D005742:Gasoline / Q000032:analysis* / Q000592:standards; D009281:Naphthalenes / Q000032:analysis; D012015:Reference Standards; D017550:Spectroscopy, Fourier Transform Infrared; D019265:Spectroscopy, Near-Infrared / Q000295:instrumentation*
D005742:Gasoline; D009281:Naphthalenes