GC Analysis of Agriculture Pesticides in Orange (Spiked) on SLB®-5ms after QuEChERS Cleanup using Primary-Secondary Amine (PSA)
Materiales
analytical column
CONDITIONS
sample preparation
SPE (Solid Phase Extraction)
sample/matrix
15 g of ground-up orange, 75 μL of the internal standard stock solution (ethoprophos at 20 ppm in methanol), 75 μL of the pesticide stock solution (29 pesticides, each at 20 ppm in methanol)
column
SLB-5ms, 30 m x 0.25 mm I.D, 0.25 μm (28471-U)
oven
100 °C (1 min), 10 °C/min to 300 °C (5 min)
inj. temp.
250 °C
MSD interface
300 °C
scan range
selected ion monitoring (SIM), 7 monitoring groups used
carrier gas
helium, 1 mL/min constant
injection
1.0 μL pulsed (20 psi until 0.20 min), splitless (1.0 min)
liner
4 mm I.D., single taper
sample
extract of an orange spiked with a 29-component pesticide mix plus 1 internal standard, each at 100 ppb
Descripción
Analysis Note
Chromatograms of the spiked orange samples are presented in the Figure. Several background peaks eluting prior to nine minutes are due to impurities in the toluene. Despite extract cleanup, matrix peaks are also present in the chromatograms. Further sample cleanup may be possible by increasing SPE sorbent weight. Nevertheless, all pesticides were detected. A first order fit was used for calibration. Linearity for the five-point calibration curves was excellent, with 28 of the 29 pesticides having r2 values >0.995 at a range of 50-500 ppb. Proper calibration of imazalil was not possible due to its presence in the orange blanks.
Legal Information
SLB is a registered trademark of Merck KGaA, Darmstadt, Germany