Time optimization of 90Sr determinations: sequential measurement of multiple samples during decay of 90Y

This work presents an optimized method for the determination of multiple samples containing ⁹⁰Sr when its daughter ⁹⁰Y is measured after chemical separation and in sequence, i.e. during its decay. Consequently the measurement times will increase for each subsequent sample, since there has been a longer time for decay before measurement. Compared to a previously published approach, when ⁹⁰Y is measured during its ingrowth, the gain in total analysis time (time for ingrowth+ summation of measurement times) is not that large, particularly not for low background instruments. However, results for a large part of the samples can be delivered earlier.

     

High-throughput enzymatic method for enantiomeric excess determination of O-acetylated cyanohydrins

The reaction yield and enantiomeric excess of O-acetylated cyanohydrin reaction products from a library of chiral catalysts can be analyzed by a three-step screening method. Alcohol dehydrogenase and NADH are used to analyze unreacted substrate. A lipase with absolute specificity converts one enantiomer to a quantifiable product before the remaining enantiomer is hydrolyzed with an unspecific esterase and quantified.