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AssigneeMillipore Corporation
InventorsUwe D. Neue, Carsten L. Niederlaender, John S. Petersen
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Novel carbamate compounds, novel silylcarbamate compounds and novel reversed phase materials comprising a silica substrate modified with a modified novel silylcarbamate compound are disclosed which may, for example, be used as stationary phases for liquid chromatography applications. Attached to the carbamate group are several reversed or normal phase producing groups such as cyanoalkyl, tertiary butyl, dibutyl, octyl, dodecyl, tetradecyl, octadecyl or benzyl. The new stationary phases may be endcapped with a short chain alkyl silane. One particular advantage of these stationary phases is decreased interaction with basic samples due to shielding of the unreacted silanol groups on the silica surface. The new phases are particularly useful in the chromatographic analysis of basic samples or more generally for samples having an undesirable interaction with the unmodified silanols.
A surface modified silica of the formula III, ##STR11## wherein l, m, o, r, s, t and u are 0 or 1, n is 0,1, 2 or 3 p is 0,1,2,3 or 4 and q is an integer from 0 to 19;
A silica having a surface to which is bonded 1 to 7 .mu.eq/M.sup.2 of Si(R.sub.7).sub.v (CH.sub.2).sub.3 O(CO)N(CH.sub.2).sub.p H(CH.sub.2).sub.q R.sub.3, wherein R7 is methyl or ethyl, v is 0,1 or 2, p is 0,1,2,3 or 4, q is an integer of 0 and 19 and R.sub.3 is selected from the group consisting of cyano, phenyl and hydrogen.
Dependencies are inferred from the claim text.