Atmospheric Solid Analysis Probe and Modified Desorption Electrospray Ionization Mass Spectrometry for Rapid Screening and Semi-Quantification of Zilpaterol in Urine and Tissues of Sheep

• Published in: Journal of agricultural and food chemistry 2018-10, Vol.66 (41), p.10871-10880
• Main Authors: Chakrabarty, Shubhashis, Shelver, Weilin L, Hakk, Heldur, Smith, David J
• Format: Article
• Language: English
• Subjects: animal tissues; Animals; Body Fluids - metabolism; Chromatography, High Pressure Liquid - methods; desorption; detection limit; Drug Residues - analysis; electrospray ionization mass spectrometry; High-Throughput Screening Assays - methods; Humans; hydrochloric acid; ionization; kidneys; Limit of Detection; liquid chromatography; liver; lungs; muscles; rapid methods; screening; sheep; Sheep - metabolism; Spectrometry, Mass, Electrospray Ionization - methods; tandem mass spectrometry; Tandem Mass Spectrometry - methods; Trimethylsilyl Compounds - metabolism; Trimethylsilyl Compounds - urine; urine; zilpaterol hydrochloride
• ISSN: 0021-8561; 1520-5118; 1520-5118
• DOI: 10.1021/acs.jafc.8b03925

Ambient ionization mass spectrometric methods including desorption electrospray ionization (DESI) and atmospheric solid analysis probe (ASAP) have great potential for applications requiring real-time screening of target molecules in complex matrixes. Such techniques can also rapidly produce repeatable semiquantitative data, with minimal sample preparation, relative to liquid chromatography–mass spectrometry (LC–MS). In this study, a commercial ASAP probe was used to conduct both ASAP-MS and modified DESI (MDESI) MS analyses. We conducted real-time qualitative and semiquantitative analysis of the leanness-enhancing agent zilpaterol in incurred sheep urine, kidney, muscle, liver, and lung samples using ASAP-MS and MDESI MS. Using ASAP, limits of detection (LOD) and quantitation (LOQ) in urine were 1.1 and 3.7 ng/mL, respectively, while for MDESI MS they were 1.3 and 4.4 ng/mL, respectively. The LODs for tissues were 0.1–0.4 ng/g using ASAP, and 0.2–0.6 ng/g with MDESI MS. The LOQs of the tissues in ASAP were 0.4–1.2 ng/g and 0.5–2.1 ng/g in MDESI MS. Trace levels of zilpaterol were accurately analyzed in urine and tissues of sheep treated with dietary zilpaterol HCl. The correlation coefficient (R 2) between semiquantitative ASAP-MS and MDESI MS results of urine samples was 0.872. The data from ASAP and MDESI MS were validated using LC–MS/MS; urinary zilpaterol concentrations ≥5.0 ng/mL or tissue zilpaterol concentrations ≥1.5 ng/g were detected by ASAP and MDESI MS, respectively, 100% of the time. Forty samples could be analyzed in triplicate, directly from biological matrixes in under an hour.