Establishment of signal-recovery functions for calculation of recovery factor. Application to monitoring of contaminant residues in vegetables by chemiluminescence detection.
A new strategy is proposed for verifying if recovery factor is constant and independent of the real analyte content of samples. A signal-recovery function has been developed on the basis of measurement of spiked test samples before and after a pre-treatment step and considering, as starting point, a recent IUPAC recommendation which distinguishes between two terms--recovery factor, R, and apparent recovery, R*. Apparent recovery includes recovery factor and a new recovery term proposed in a previous paper by the authors, named calibration recovery, R(C). The signal-recovery function is obtained directly from the measured analytical signals instead of from the concentrations, simplifying the calculations. A linear signal-recovery curve indicates that the recovery factor is constant in the analyte concentration range studied experimentally and, in this way, a single recovery factor can be calculated. The usefulness of the proposed method has been shown by quantification of the pesticide carbaryl by two different flow-injection analysis methods with chemiluminescent detection based on the luminol and TCPO systems. Good results were obtained from both methods.
Gámiz-Gracia
Laura
L
Department Analytical Chemistry, Faculty of Sciences, University of Granada, 18071, Granada, Spain. lgamiz@ugr.es
Cuadros-Rodríguez
Luis
L
Soto-Chinchilla
Jorge J
JJ
Huertas-Pérez
José F
JF
González-Casado
Antonio
A
García-Campaña
Ana M
AM
D005506:Food Contamination / Q000032:analysis*; D008163:Luminescent Measurements / Q000379:methods*; D014675:Vegetables / Q000737:chemistry*