8-Chloro-6-(trifluoromethyl)imidazo[1,2-a]pyridine-2-carboxylic acid

Additional information on environmental fate and behaviour

Administrative data

Endpoint:

additional information on environmental fate and behaviour

Remarks:

storage stability

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2017

Report date:

2017

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

other: OECD 506: Stability of Pesticide Residues in Stored Commodities

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

other: European Communities Guideline for the Generation of Data Concerning Residues, as provided in Annex II, Part A, Section 6 and Annex III, Part A, Section 8 of EC Commision Directive 91/414/EEC.

Deviations:

no

GLP compliance:

yes

Type of study / information:

storage stability

Test material

Test material information

1

Reference substance name:

8-chloro-6-(trifluoromethyl)imidazo[1,2-a]pyridine-2-carboxylic acid

Cas Number:

353258-35-2

Molecular formula:

C9H4ClF3N2O2

IUPAC Name:

8-chloro-6-(trifluoromethyl)imidazo[1,2-a]pyridine-2-carboxylic acid

Specific details on test material used for the study:

Test substance: IN-QEK31
Batch No.: IE114893-105
Purity: 98.6%

Results and discussion

Any other information on results incl. tables

Table 1: Parent recoveries

	IN-QEK31
Fresh fortifications	89.8 ± 9.0
Aged fortifications	91.8 ± 11.9

 

Applicant's summary and conclusion

Conclusions:

Residues of IN-QEK31 are stable when stored frozen in both soil types at approximately -20°C for up to 24 months.

Executive summary:

A number of field and laboratory studies were conducted with DPX-Q8U80 in which the soils containing residues of the parent compound and its metabolites were stored frozen while awaiting analysis. In order to demonstrate that the residues were stable during freezer storage, a storage stability study was conducted on two representative soils which were treated with DPX-Q8U80 and its soil metabolites (IN-QEK31, IN-VM862, IN-RYC33, IN-F4106, IN-A5760 and IN-REG72) and stored under conditions similar to those used for storage of samples for the field and laboratory studies. These fortified samples were analyzed at 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 21 and 24 months. This stability study was designed to cover the longest interval between sample collection and the analysis of these soils for the residues of DPX-Q8U80 and its soil degradates, which were stored frozen at approximately -20°C.

Two soils, representative of field sites chosen for the field dissipation studies were selected for this study. The soils were obtained from the field study sites in Italy [Graffignana] (used for study reported in DuPont-36980), and France [Nambsheim] (used for study DuPont-36981). Two sets of soil samples, Set A and Set B, were fortified with the respective analytes at a level of 20 μg/kg of each analyte, and stored at approximately -20ºC. Set A samples were fortified with (DPX-Q8U80, IN-QEK31, IN-VM862 and IN-RYC33) and Set B with (DPX-Q8U80, IN-F4106, IN-A5760 and IN-REG72). At each analysis time point, fresh soil samples were fortified with all respective analytes at a level of 20 μg/kg. The samples were analyzed at ca 0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 21 and 24 months.

Samples were analyzed using the analytical method which had been used in the analysis of the terrestrial field dissipation study samples. Residues of DPX-Q8U80, and soil metabolites IN-QEK31, IN-VM862, IN-RYC33, IN-F4106, IN-A5760 and IN-REG72 were extracted from soil by a 2 step sequential extraction procedure. Extraction solution used was 1/1 (v/v) 2% formic acid (aq)/acetonitrile. The two extractions were combined and diluted to 35mL with water. A 7 mL aliquot was removed from each extract before passing it through Oasis HLB SPE 6 mL (0.5g) cartridge. The cartridges were rinsed with 5 mL 20/80 (v/v) acetonitrile/water prior to be eluted using 12mL of 50mM ammonium formate in 50/50 (v/v) acetone/acetonitrile. Collected eluates were evaporated under a flow of nitrogen to 2 mL in a heated dry-block set at 35 ºC. Once reached the volume, an aliquot of 3 mL of methanol was added and the extracts were concentrated to 2 mL. These samples were then diluted up to 10 mL with water and filtered prior to be analyzed using reverse phase HPLC separation coupled to tandem mass spectrometry (LC-MS/MS).

Fresh fortified soil samples were analyzed concurrently in each analysis set. The average recoveries in the freshly fortified and frozen fortified soil samples for both soil types were comparable over the entire 24-month period.

Examination of average recoveries and standard deviations for DPX-Q8U80 and soil metabolites shows that the individual fresh fortification recoveries, as well as the frozen fortification recoveries, were in general normally distributed and within the range of method capability. The recoveries for all analytes at each sampling interval were also generally within the range of expected variability for the analytical method. For all analytes there was no discerable trend of decreasing recoveries in the frozen stored samples over time.

It can be concluded that the residues ofDPX-Q8U80 and soil metabolites are stable in frozen soil over 24 months.