Development and validation of an ultra-performance liquid chromatography method for the determination of bis(2,4-di-tert-butylphenyl)phosphate and related extractable compounds from single-use plastic films

A UPLC-UV method is described for the detection of bDtBPP and related breakdown compounds of Irgafos 168 from single-use bioprocessing bag films using a CSH (charged surface hybrid) fluoro phenyl column and UV detection at 220 nm. The method limits of detection were between 16 μg L‐1 and 60 μg L‐1, repeatability was %RSD ≤ 1.8 and linearity was R2 ≥ 0.9992. The method was applied to an extractables and leachables test of three single-use bioprocessing bag films. bDtBPP and oxidised Irgafos were detected from all three films in the extractables study, but not in the leachables study. A comparison of whole bag and small scale film extractions demonstrated that the small scale extractions were more suitable for finding concentration per area of film and/or estimating total load of extractables in the entire bag. The feasibility of upstream monitoring of extractable and leachable compounds with the Waters PATROL UPLC System via a Flownamics® sampling probe was also tested with cell growth medium spiked with bDtBPP. bDtBPP was only detected in at-line injections or online injections when the probe membrane was removed indicating that with the current sampling interface, monitoring of extractables and/or leachables is limited to at-line sampling.