Determination of the acaricide fenbutatin oxide in water samples by automated headspace‐SPME‐GC/MS

The analysis of the acaricide fenbutatin oxide (FBTO) having a molecular weight of 1052.66 g mol –1 in water samples by capillary GC/MS after in‐situ derivatization with sodium tetraethylborate (NaBEt 4 ) and headspace‐SPME enrichment is described. Automated SPME is performed at 80°C for 30 min. Detection is carried out in the ion monitoring mode with deuterated triphenyltin (TPhTd15) as internal standard. Good linearity ( R  2 = 0.9993) was obtained in the dynamic range 20 to 1000 ng L –1 with a limit of detection of 16 ng L –1 (LOD at 3 S/N  ) and a limit of quantitation of 50 ng L –1 (LOQ at 10 S/N  ). Intra‐day RSD% for n = 6 was 8.9 at the LOQ level.