Nature of residue studies are performed using ¹⁴C-radiolabeled compound in order to determine the distribution of radioactive residues within the various tissues/crop matrices and to determine the degradation pathway. Nature of residue studies (OECD 501, OECD 502, OECD 503 and OECD 507) are performed in our laboratories by expert and experienced staff. Total radioactive residue, extractable residue, determination/characterization of bound residues (post extracted solids), matrix clean-up, and characterization / radio-profiles of the radioactive residue are tailored and performed to satisfy routine and challenging projects with exceptional care and quality.
 
Elucidating the structure of novel metabolites is often technically challenging and requires the attention of experienced metabolite ID chemists in conjunction with the advanced chromatographic and mass spectrometry instrumentation in our laboratories. The combination of our experts and state-of-the-art instruments ensure that we provide an efficient metabolite profiling and identification service.
 
Once the nature of the residue has been determined by our experts in Metabolism, our Residue team experts are on hand to guide the Sponsor through any follow-on studies that may be needed to determine the magnitude of the pesticide residues.
 
View our published scientific posters about Metabolism testing.
See the full list of Metabolism studies.

Metabolism in Crops

Crop studies are conducted to determine the nature of pesticide residue in primary crops or in rotational crops. Our plant metabolism experts conduct the in-life phase either on site in our greenhouses or using trusted partner sites.

• Plant metabolism studies in all primary crop groups
• Confined rotational crop studies
• Greenhouse radiolabeled studies 
• Outdoor radiolabeled studies 
• Formulation preparation (EC, SC, WP, etc.)
• Processing and stability investigations
• Translocation investigations

 
Metabolism in Livestock

We conduct the in-life phase of animal metabolism studies, in goat and poultry, at trusted partner facilities. We work with sponsors to design and plan every detail of a study to best meet the product development and/or regulatory compliance needs. 
 
Other Metabolism in Rat and Fish
 

• Pharmacokinetic and tissue distribution in rat (OECD 417)
• Metabolism in fish (SANCO/11187/2013)

  
In vitro Metabolism

Use of in vitro studies to provide comparative metabolism information is a powerful tool that is faster and more cost effective than in vivo studies. Smithers is at the forefront of exploratory and regulated in vitro approaches for both plants and animals.

• Species comparative metabolism
• New metabolite identification
• Metabolic stability
• Early evaluation of metabolism in both plant and animal species
• Metabolic synthesis of standards
• Whole cells, extracts, subcellular fractions
• Tissue extracts

 
Analytical Capabilities
 

• Thermo Scientific™ Orbitrap Eclipse™ Tribrid™ with Vanquish™ Horizon 2D-UHPLC system
  • Provides exceptional chromatographic resolution
  • Metabolite ID with accurate mass multi-stage Ion Trapping (MSⁿ )
  • 2D-UHPLC enables separation of isomers and isolation of co-eluting metabolites from complex matrices in animal and plant metabolism studies and increases the 2D-HPLC capacity in the UK laboratory to three instruments
• Sciex QTRAP™ 6500+ mass spectrometers combined with differential ion mobility technology, enables separation of isobaric species, elimination of background noise, isolation of challenging co-eluting contaminants, and analysis of some stereoisomers. Includes a large-capacity rack changer to house over 500 samples for analysis.
• Triple-quadrupole Sciex 4000 QTRAP™, full-scan MS, MS/MS, and MS3spectra with high selectivity from true triple quadrupole precursor ion (PI), and neutral loss (NL), and multiple reaction monitoring (MRM) scans
• Accurate mass Sciex Triple TOF™ 5600 and 5600+, high-resolution and high mass-accuracy MS/MS data using powerful IDA algorithms and high-resolution, accurate-mass MS and MS/MS.The systems have the latest data interrogation software from Sciex
• The new Nexera™ LC-40 system includes a Liquid Handler (fraction collector and injector in one), and both photodiode array and Beta-RAM 5 detectors.
• HPLC/RAM for chromatographic separation and radiodetection
• Biological oxidizers for TRR determination and bound residue determination
• Extensive experience in thin layer chromatography (TLC) with plate spotters available for complex profiling of low level samples.