CAS#14314-42-2 | 18O Water

Proteolytic Labeling With 18O for Comparative Proteomics Studies: Preparation of 18O-Labeled Peptides and the 18O/16O Peptide Mixture

are first cleaved with trypsin in water, and subsequently the peptide products are dried and labeled by incubation with trypsin in 18 O-enriched water. One important aspect of this two-step procedure is that peptides, and not proteins, are dried

水势（water potential）

　　 以纯水的化学势（μ o w ）作为标准，在等温等压下一定体系中水的化学热（μ w ）与该标准之差，除以水的偏摩尔体积（ Vw ）所得之商值称为该体系的水势（ψ w ）。   　　其单位为“压力”单位，通常以巴表示。按国际单位制以帕（ pa）表示。将纯水的水势定为零，其他体系如水溶液的水势均为负值。水势的定义是从水的化学势导出，它以能量为单位。自然界自发过程的方向是：能量从较高水平向较低水平移动。渗透作用所以能发生是因为在半透膜两边存在

Automated Trace Analysis of Pesticides in Water

acidified (pH 3.0) samples are processed. The on-line HPLC analysis is carried out on a C18 analytical column eluted with a binary gradient of 10 mM phosphate buffer and an acetonitrile/water (90:10 v/v) mixture. Solutes are tentatively identified by tandem