Determination of residue levels of the avicide 3-chloro-4-methylaniline hydrochloride in red-winged blackbirds (Agelaius phoeniceus) by gas chromatography-tandem mass spectrometry

The avicide 3‑chloro‑4‑methylanaline hydrochloride (chloro‑p‑toluidine hydrochloride, CPTH, DRC-1339) is used to control pest bird species that damage agricultural crops. A specific and sensitive gas chromatography-tandem mass spectrometry method was developed and validated for the determination of CPTH in avian breast muscle, GI tract, kidney, and liver. Tissue samples were extracted with a solution of acidified water and acetonitrile. The sample was made basic and cleaned up with a combination of liquid-liquid partitioning and solid phase extraction. Separation was achieved using a HP-5 ultra-inert GC column (15 M, 0.25 μm film) with detection on a triple quadrupole mass spectrometer in multiple reaction monitoring (MRM) mode. The monitored transition for CPTH was m/z 140.9 → 106.2 for quantitation and 139.9 → 105.2 and 139.9 → 77.2 for confirmation. The linear range was 5 to 5000 ng/mL. The precision for the determination of CPTH in all tissues averaged 7.2% and the accuracy averaged 6.7%. The recovery of CPTH fortified at 5 different levels averaged 101% in liver, 98.8% in GI tract, 92.9% in breast muscle, and 87.9% in kidney. The established method was successfully used to determine CPTH residue levels in red-winged blackbirds exposed to three different doses of CPTH.