108139-1 Study Title Data Requirements Author Study ... - IR-4 Project

Bayer Corporation 108139-1
Agriculture Division
4.2 Addition of Internal Standard Solution
A standard containing the deuterated standard was added immediately after the extraction to
account for any loss during sample clean-up. The addition was made using the same accurate
pipette for each addition. The accuracy of the pipette was important since the response factors
calculated in the sample extracts were compared to the response factor of the quantification
standard, which was made using an accurate pipette.
4.3 GC/MS of Cyfluthrin
In the current method, the gas chromatography procedure in combination with the mass
spectrometer using negative chemical ionization was selected to replace the gas
chromatographic/mass spectrometry procedure using positive electron impact ionization. This
modification was performed to increase sensitivity and selectivity thus reducing the amount of
clean-up. In addition, the use of an internal standard compensated for loss during sample
clean-up. Due to the increase in sensitivity, less sample was required to maintain an LOQ of
0.01 ppm.
Figures 5 through 144 show typical negative chemical ionization selected ion monitoring (SIM)
ion-chromatograms of cyfluthrin, and [ 2 H6]cyfluthrin standard solutions and matrix extract
solutions. Cyfluthrin is represented by ion m/z 207. [ 2 H6]Cyfluthrin is represented by ion
m/z 213. Proposed fragmentation of Cyfluthrin is shown in Appendix 4.
The presence of eight diastereomers (four pairs) in cyfluthrin creates three peaks that are not
base line resolved. All three peaks are integrated as one peak area and used to quantitate
cyfluthrin.
4.4 Recovery of Cyfluthrin
Tables 1 through 28 list data for recoveries, control values, standard deviations, and average
recoveries for cyfluthrin from various plant matrices. Figures 5 through 144 show typical
chromatograms of standards and control samples, and recovery samples for various plant
matrices. All recoveries cyfluthrin at all fortification levels fell within the 70% to 120% range
except for the 6.5 ppm fortifications in peanut hay which were just below 70%.
4.5 Limits of Quantitation and Detection (Except Apple and Pears)
The limits of quantitation (LOQ) based on the lowest ppm levels fortified of were 0.01 ppm for all
the plant matrices analyzed.
The limit of detection (LOD) is defined as the lowest concentration that can be determined to be
statistically different from a blank or negative control. The LOD was calculated by taking the
standard deviation of the residue values from the analysis of the recovery samples at the LOQ
and using the equation shown below:
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