Simultaneous determination of oxalate and citrate in urine and serum of calcium oxalate kidney stone rats by IP-RP LC-MS/MS

•This method is suitable for the quantification of oxalate and citrate both in serum and urine samples.•Ion-pairing reagents have good application in the detection of oxalate and citrate.•The optimized method can obtain shorter analysis time, higher sensitivity and better separation than methods reported.•The assay of oxalate and citrate contributes to the diagnosis and monitoring of kidney stones.