Electrospray ionization mass spectrometry adduct formation by mobile phase additives: A case study using nitrile functional groups containing selective androgen receptor modulators

Abstract

Rationale: The formation of mass adducts is common during electrospray ionization mass spectrometry (ESI-MS). However, the mechanism that leads to adduct formation is poorly understood and difficult to control. Multiplication of mass adducts at once will adversely impact the sensitivity of mass analysis and cause misinterpretation of the level of detection. Prior studies on selective androgen receptor modulators (SARMs) revealed an immense mass adduct formation in both positive and negative ESI modes.Methods: In this study, additives in the mobile phases are investigated as a potential means of controlling mass adduct formation in various SARMs. Results:The first evidence of chloride adduct formation when SARMs are detected via ESI-MS has been reported in this research. A series of mobile phase combinations were tested to achieve the optimal condition for HPLC-MS. A comparison was also made between adduct formation on various grades of water used for preparing the mobile phase. A validation study using equine urine and plasma was also conducted to assess the suitability of the developed method. Conclusion:The results of this study will allow for a more accurate identification of SARMs, which will make it easier to investigate their illicit use in horse racing. | INTRODUCTIONIn mass spectrometers, molecule fragmentation is dependent on the stability of molecular ions. As a result, the fragmentation pattern of a molecule can be reproduced, and it contains valuable information about its chemical structure. The term adduct refers to a version of a

Doping control approach: Identification of equine in vitro metabolites of voxelotor (GBT440), a hemoglobin S polymerization inhibitor

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An extensive screening method for the identification and quantitation of ecdysteroids in equine urine and plasma using liquid chromatography coupled with mass spectrometry

“…The method validation 37–40 for drugs on investigation was carried out using Selectra PFPP column (3 μm, 15 cm × 4.6 mm, UCT) at a flow rate of 0.5 mL/min was used for the chromatographic separation, and the sample was eluted with 0.2% formic acid in water (mobile phase A) and ACN (mobile phase B) in gradient elution mode. The column temperature was kept at 50°C.…”