R. Marsilio et al., SIMULTANEOUS HPLC DETERMINATION WITH LIGHTSCATTERING DETECTION OF LACTULOSE AND MANNITOL IN STUDIES OF INTESTINAL PERMEABILITY IN PEDIATRICS, Clinical chemistry, 44(8), 1998, pp. 1685-1691
We describe a new HPLC method for the simultaneous determination of la
ctulose and mannitol in urine, in which cation-exchange chromatography
and evaporative light-scattering detection are used. The two sugars a
re orally administered for the estimation of intestinal permeability i
n children. Samples were purified by solid phase extraction on a C-18
cartridge and subsequent addition of anion-exchange resin. Cellobiose
may be used as an internal standard. The chromatographic separation wa
s carried out in 16 min at a flow rate of 0.5 mL/min, using deionized
water as the mobile phase. Within-run precision (CV) measured at three
concentrations was 1.6-2.3% for lactulose and 1.0-1.9% for mannitol.
Between-run CVs were 2.1-4.1% and 1.3-2.7% for lactulose and mannitol,
respectively. Analytical recovery of both sugar probes was 97-101%. T
he detection limits (signal-to-noise ratio = 3) were 0.82 mg/L for lac
tulose and 0.65 mg/L for mannitol. The lactulose/mannitol ratio in con
trol subjects was 0.024 +/- 0.006; in patients with Crohn's and coelia
c diseases in active phase, the ratios were 0.200 +/- 0.082 and 0.072
+/- 0.025, respectively. The method is rapid, simple, and sensitive, a
nd suitable for determination of intestinal permeability in children.