An efficient and short route has been elaborated for the aminopropyl spacer equipped Leb hexasaccharide. For the prepn. of HSA-conjugates of this oligosaccharide, the use of disuccinimidyl suberate (DSS) and disuccinimidyl glutarate (DSG) as cross-linker reagents has been evaluated. This conjugation method emerged as being faster and easier to monitor by std. MALDI-TOF spectrometry than squarate ester based conjugations of similar efficiency if DSS is used as cross-linker. [on SciFinder (R)]