Full-scan accurate mass selectivity of ultra-performance liquid chromatography combined with time-of-flight and orbitrap mass spectrometry in hormone and veterinary drug residue analysis.
The applicability of ultra-performance liquid chromatography (UPLC) combined with full-scan accurate mass time-of-flight (TOF) and Orbitrap mass spectrometry (MS) to the analysis of hormone and veterinary drug residues was evaluated. Extracts from blank bovine hair were fortified with 14 steroid esters. UPLC-Orbitrap MS performed at a resolving power of 60,000 (FWHM) enabled the detection and accurate mass measurement (<3 ppm error) of all 14 steroid esters at low ng/g concentration level, despite the complex matrix background. A 5 ppm mass tolerance window proved to be essential to generate highly selective reconstructed ion chromatograms (RICs) having reduced background from the hair matrix. UPLC-Orbitrap MS at a lower resolving power of 7500 and UPLC-TOFMS at mass resolving power 10,000 failed both to detect all of the steroid esters in hair extracts owing to the inability to mass resolve analyte ions from co-eluting isobaric matrix compounds. In a second application, animal feed extracts were fortified with coccidiostats drugs at levels ranging from 240 to 1900 ng/g. UPLC-Orbitrap MS conducted at a resolving power of 7500 and 60,000 and UPLC-TOFMS detected all of the analytes at the lowest investigated level. Thanks to the higher analyte-to-matrix background ratio, the utilization of very narrow mass tolerance windows in the RIC was not required. This study demonstrates that even when the targeted sample preparation from conventional LC-MS/MS is applied to UPLC with full-scan accurate mass MS, false compliant (false negative) results can be obtained when the mass resolving power of the MS is insufficient to separate analyte ions from isobaric co-eluting sample matrix ions. The current trend towards more generic and less selective sample preparation is expected to aggravate this issue further.
van der Heeft
E
E
RIKILT-Institute of Food Safety, Wageningen, The Netherlands. ed.vanderheeft@wur.nl
Bolck
Y J C
YJ
Beumer
B
B
Nijrolder
A W J M
AW
Stolker
A A M
AA
Nielen
M W F
MW
D000821:Animal Feed / Q000032:analysis; D000818:Animals; D002417:Cattle; D002853:Chromatography, Liquid / Q000379:methods*; D003049:Coccidiostats / Q000032:analysis; D004350:Drug Residues / Q000032:analysis*; D005188:False Negative Reactions; D006197:Hair / Q000737:chemistry; D013058:Mass Spectrometry / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013256:Steroids / Q000032:analysis*; D019155:Veterinary Drugs / Q000032:analysis*
D003049:Coccidiostats; D013256:Steroids; D019155:Veterinary Drugs