Determination of methyl bromide residues in tea by headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry

Figures (7) Tables (1)

Figure 1.
The extracted ion chromatograms of m/z 94 for (a) non-spiked and (b) spiked tea samples and (c) the SIM mass spectrum of methyl bromide.
Figure 2.
Peak area of methyl bromide using different kinds of extraction fibers.
Figure 3.
Peak area of methyl bromide at different extraction temperatures and times.
Figure 4.
Peak area of methyl bromide at different sodium chloride additions.
Figure 5.
Peak area of methyl bromide at different pH values.
Figure 6.
Peak area of methyl bromide under different desorption temperatures and times.
Figure 7.
Changes of methyl bromide residues in fumigated tea stored in sealed conditions at −20 °C.
Compound Spiked levels, (mg·kg⁻¹)
0.15 0.3 1.0
Recovery (%) RSD (%) Recovery (%) RSD (%) Recovery (%) RSD (%)

Methyl bromide 102.4 6.1 107.7 3.0 95.0 0.4

Table 1.
Precision and accuracy of methyl bromide residues in tea obtained by SPME/GC-MS.