Capillary electrophoresis and phenylboronic acid solid phase extraction for the determination of S‐adenosylmethionine/S‐adenosylhomocysteine ratio in human urine

Abstract

An approach that allows direct analysis of the ratio of S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) by using CE is presented. The analytes were extracted on phenylboronic acid phase and eluted with 100 mmol/L HCl. CE separation of the analytes took place in the transient isotachophoresis mode with addition of NaCl and meglumine to the samples. The sensitivity (S/N = 3) and quantification limit (S/N = 10) of the method were 0.07 and 0.2 μmol/L, respectively, using a silica capillary with 50 μm internal diameter and 30.5 cm total length. The BGE was 0.02 mol/L Tris with 1 mol/L HCOOH (pH 2.2), and the separation voltage was 15-17 kV. Accuracy of SAM and SAH analysis in urine was 96 and 105%, respectively; interday precision for the SAM/SAH ratio was within 6%. The theoretical plate number exceeded a million. Total analysis time was 8.5 min.

Determination of S‐adenosylmethionine, S‐adenosylhomocysteine, and methylthioadenosine in urine using solvent‐modified micellar electrokinetic chromatography

“…We used a previously proposed method, based on SPE with the use of grafted PBA with some modifications: 70 µL of 400 mM Na‐phosphate buffer (pH 8.0) and 30 µL of 100 µM ATPA/calibrate solution were added to 300 µL of urine immediately prior to SPE; 10 mg of the Bond Elute‐PBA phase (Agilent, USA) was washed with 30% ACN + 1% (w/w) HCOOH (0.2 mL), water (0.4 mL), and 50 mM Na phosphate buffer (pH 8.0; 0.4 mL). The sample (0.4 mL) was loaded, and the phase was flushed with 50 mM Na‐phosphate buffer (pH 8.0; 0.4 mL) and 10 mM Na phosphate buffer (pH 8.0; 0.4 mL).…”

“…However, this approach was unsuitable for blood and urine analysis and required significant modification. Previously, guided by this strategy, we proposed the use of CITP in combination with SPE for SAM and SAH determination in urine . As a result of the concentration of analytes in the capillary and SPE, the quantification limit was 0.2 µM.…”

Recent progress in analytical capillary isotachophoresis

“…Recoveries in spiked sewage samples were 94–104%. Ivanov and co‐workers developed a method for direct determination of the ratio of S‐adenosylmethionine and S‐adenosylhomocysteine in human urine. The analytes were extracted on a phenylboronic acid phase and eluted with 100 mM HCl.…”

“…UV detection records of the sample with addition of (A) 105 mM NaCl and 26 mM NaOH, and (B) 105 mM NaCl, 26 mM NaOH and 10.5 mM N‐methyl‐D‐glucamine which assisted in additional stacking of SAH and its separation from Ado. Reprinted from with permission.…”

Recent advances in CE and microchip‐CE in clinical applications: 2014 to mid‐2017

“…Using a similar approach, methoxyphenols, and polycyclic aromatic hydrocarbons were analyzed in skin wipe samples from firefighters . Other small molecules analyzed by CE in various human fluids and cells are uric acid in urine , S–adenosylmethionine, and S‐adenosylhomocysteine in urine , iodine in urine , cyanide in urine samples from smokers and nonsmokers , gamma‐aminobutyric acid in CSF , oxalate, formate, and glycolate in human biofluids , malondialdehyde in exhaled breath condensate , and reduced glutathione and glutathione in red blood cells .…”