Synthesis and characterisation of non-bonded 1.7 μm thin-shell (TS1.7-100 nm) silica particles for the rapid separation and analysis of uric acid and creatinine in human urine by hydrophilic interaction chromatography

•A new non-bonded 1.7 μm thin-shell (TS1.7-100 nm) silica particle for HILIC.•Separation time controllable to sub-1 min on sub 2 μm particle column.•Rapid HILIC method applicable for selective determination of uric acid and creatinine in urine.

A rapid chromatographic method for the simultaneous determination of uric acid (UA) and creatinine (Cr) in human urine is described, using a non-bonded 1.7 μm thin-shell (TS1.7-100 nm) silica particle prepared by the seeded-growth approach. The new shell particle was characterised by scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS) and BET analysis. TEM reveals 1.5 μm solid core and 100 nm shell thickness. DLS shows polydispersity index <0.2. Expanded pore size of 88 Å and specific surface area of 78 m2/g were determined by BET. Chromatographic results demonstrate that UA, Cr and hypoxanthine (Hyp, as internal standard) can be separated in less than 1 min on the in-house packed TS1.7-100 column (4.6 ID x 100 mm), using chromatographic conditions with mobile phase 70% acetonitrile, 10 mM ammonium acetate buffer, pH 6.78, flow rate 1.25 ml/min and UV detection at 254 nm. A linear relationship between the ratio of the peak area of the standard UA and Cr to that of the internal standard (Hyp) and the concentration of standards was obtained for both UA and Cr with the square of the correlation coefficients, R2 = 0.998 for both renal biomarkers. The calculated detection limits were 0.03 μg/ml and 0.05 μg/ml for UA and Cr respectively. Urine samples tested were found to contain UA and Cr in the concentration range of 782-1206 μg/ml and 535-862 μg/ml respectively. The recovery ranges for spiked urine standards were 85.7-93.2% for UA and 91.9-94.6% for Cr and the relative standard deviations (RSD) for both biomarkers were 3.05% and 0.88% respectively. The developed rapid HILIC method can have application in determining the concentrations of UA and Cr for early prediction in patients with developing disease conditions, including acute kidney injury (AKI).