For validation of the method, the limit of detection (LOD), limit
of quantification (LOQ), recovery, and accuracy were measured.
LOD and LOQ were determined on the basis of the detector
signal-to-noise ratio and a calibration curve (Dias, Camões, &
Oliveira, 2008). LOD was determined by means of the expression
‘‘3.3 standard deviations (SD) slope” and was based on SD of
the peak areas of the MDA standard solution at a concentration
near the blank. LOQ was calculated by using the factor of 10
instead of 3.3 in the above expression. For assessment of analytical
recovery, a 2-mL sample of hydrolysate (after incubation of 5-mL
sample of the homogenate with 1 mL of 6 M NaOH in a water bath
at 60 C for 45 min) was mixed with 1 mL of 2 M HCl to adjust pH
to neutral. After that, 1 mL of 1.6 lM TEP solution was added. The
accuracy (reproducibility) was measured by determining reproducibility
of analysis of the MDA standard solution (0.32 lM) and
of the MDA extract from a sample. The reproducibility was
expressed as the percentage of relative standard deviation (RSD
%). Quantification of MDA in the MDA standard solution was
repeated five times on the same day and additionally on five consecutive
days to determine intraday and interday variations. To
measure interday accuracy by means of the MDA extract from a
meat product sample, the filtrate of MDA extract from the sample.