Page 32 - Volume 5, Issue 2, July 2012

Dithiocarbamates and inorganic bromide residues in plant products

61

4.6 to 18.5% for inorganic bromide, meeting

the requirement of RSDs ≤20% [5]. These re-

sults are acceptable and indicate good accu-

racy and precision for both methods.

Validation was performed at two or

three fortification levels (Tables 1 and 2), at

five replicates each. The highest level was

selected to be at the maximum residue lim-

it (MRL) as set by EU Regulation 396/2005

for each product (Tables 1 and 2). Limit of

quantitation (LOQ), is defined from a regu-

latory perspective as the lowest concentra-

tion tested at which an unambiguous identi-

fication of the analyte can be proven and at

which an acceptable mean recovery with an

acceptable relative standard deviation (RSD)

is obtained [5, 11].

Linearity

Concerning CS

2

, calibration lines were

constructed from data acquired after in-

jecting calibration standards in isooctane

Figure 2.

Determination of inorganic bromide in rice. Chromatograms of rice samples blank and fortified with 50mg/kg of

bromide. The quantification is based on the ratio from the sum of the area of the two derivatives (1-bromopropanol-2 and

2-bromopropanol-1) and the internal standard (3-bromo-1-propanol).