Agriculture Reference
In-Depth Information
Analytical Quality Control
Calibration curves used for the quantitative determination were constructed on the basis
of the area under the DON chromatographic peaks, using seven DON working standard
solutions. The linearity of the method was assessed by standards ranging from 0.17-3.40
ng/μl. The correlation coefficient was 0.999. The limit of quantification (LOQ) for LC
determination based on a signal-to-noise ratio of 10:1 was 0.20 ng/μl of DON, which is
equivalent to 0.040 μg/g of DON in substrate. Recovery studies were performed on the blank
samples of soybean meal spiked at the levels of 0.70 and 1.10 mg/kg of DON. The recovery
in the former case was 89.7% (SD = 1.4) and 93.3% (SD = 1.6) in the latter. The results for
the samples were not corrected for the recovery of the spike.
R
ESULTS
Many analytical procedures have been developed for the determination of DON in feed
and food [33]. In this work the determination of DON in the collected soybean and soybean
meal samples was carried out by liquid chromatography under previously determined optimal
experimental conditions [32]. Figure 2 shows the chromatograms obtained for soybean meal
sample. As can be seen, the procedure applied for the cleaning-up of the raw soybean meal
extract and conditions used in the recording of chromatograms were satisfactory, i.e. the DON
peak is well separated from those for the matrix.
In the present study a total of 42 soybean and soybean meal samples were analyzed for
DON (Table 1).
Table 1. Occurrence of DON in soybean and soybean meal in Serbia from the
2004
−
2007 harvests
No. of
samples
No. of positive
samples (%)
Concentration in samples (mg/kg)
Year
Average
Range
Median
13
1 (7.7)
0.109
0.109
0.109
2004
11
1 (9.1)
0.100
0.100
0.100
2005
12
4 (30.0)
0.346
0.162-0.450
0.385
2006
6
1 (16.7)
0.144
0.144
0.144
2007
42
7 (16.7)
0.248
0.100-0.450
0.162
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