2134/14464
Neil A. Devenport
Neil A.
Devenport
Daniel J. Blenkhorn
Daniel J.
Blenkhorn
Daniel J. Weston
Daniel J.
Weston
Jim Reynolds
Jim
Reynolds
Colin Creaser
Colin
Creaser
Direct determination of urinary creatinine by reactive-thermal desorption-extractive electrospray-ion mobility-tandem mass spectrometry.
Loughborough University
2014
untagged
Chemical Sciences not elsewhere classified
2014-04-10 12:48:12
Journal contribution
https://repository.lboro.ac.uk/articles/journal_contribution/Direct_determination_of_urinary_creatinine_by_reactive-thermal_desorption-extractive_electrospray-ion_mobility-tandem_mass_spectrometry_/9390128
A direct, ambient ionization method has been developed for the determination of creatinine in urine that combines derivatization and thermal desorption with extractive electrospray ionization and ion mobility-mass spectrometry. The volatility of creatinine was enhanced by a rapid on-probe aqueous acylation reaction, using a custom-made thermal desorption probe, allowing thermal desorption and ionization of the monoacylated derivative. The monoacyl creatinine [M + H] ion (m/z 156) was subjected to mass-to-charge selection and collision induced dissociation to remove the acyl group, generating the protonated creatinine [M + H] product ion at m/z 114 before an ion mobility separation was applied to reduce chemical noise. Stable isotope dilution using creatinine-d as internal standard was used for quantitative measurements. The direct on-probe derivatization allows high sample throughput with a typical cycle time of 1 min per sample. The method shows good linearity (R = 0.986) and repeatability (%RSD 8-10%) in the range of 0.25-2.0 mg/mL. The creatinine concentrations in diluted urine samples from a healthy individual were determined to contain a mean concentration of 1.44 mg/mL creatinine with a precision (%RSD) of 9.9%. The reactive ambient ionization approach demonstrated here has potential for the determination of involatile analytes in urine and other biofluids. © 2013 American Chemical Society.