Use of an adsorbed chiral selector in capillary LC-MS

Lasalocid was utilized as a chiral selector adsorbed on porous graphitic carbon. Important parameters were identified for the use of the chiral selector in capillary liquid chromatography combined with MS detection. The influence on both retention and enantioselectivity as well as mass spectrometric performance was studied at lasalocid concentrations of up to 12 mg/l (20 microM). Moreover, the stability of retention factors and enantioselectivities was also evaluated at low selector concentration of 1 mg/l (2 microM). The results show that in order to optimize the MS performance the selector concentration should be kept at low microM. The chromatographic performance at reduced selector concentration (1 mg/l = 2 microM) was studied over a 10-day period, showing satisfactory enantioselectivity and stable performance concerning enantioselectivity and retention.