What is the function of end capped column?
Answers were Sorted based on User's Feedback
Answer / bhagavanji nelakanti
Masking of secondary silanol groups of bonding phase by tri
methyl silane (TMS)molecules is called as end capping. In
the bonded phase the secondary silanol molecules which shows
high polar bonding property with compound retains in the
column and those compounds elute slowly. Because of the end
capping the binding property of the secondary silanol
molecules will reduce and resulting less retention of those
compounds.
Is This Answer Correct ? | 45 Yes | 3 No |
Answer / premraj behera
All the packing material(active silanol group) has been end-capped(fixed) with trimethylsilyl/double end-capped with dimethylsilyl and trimethylsilyl group. End-capped stationary phase increase column stability and reducing the solubility rate o f the silica support, and also useful for rugged method development. Double end-capped column appears to further increase column stability.
Is This Answer Correct ? | 14 Yes | 3 No |
Answer / vinod kumar uppalli
The Si-OH functional groups of silica bed tend to ionize at higher pH and convert into negatively charged Si-O functional group and this interacts with acidic moieties and leads to tailing of peak due to secondary interactions. To overcome this most of the columns are end capped (Si-OH GROUP IS SHIELDED) to avoid secondary interactions.
Is This Answer Correct ? | 1 Yes | 0 No |
Answer / ravi kumar thota
Silica is an amorphous polymer of silicon and oxygen. This polymer terminates at the surface of the particle as –Si-OH groups, commonly called “silanols.” These silanol groups serve as attachment sites for the bonded phase. A silane reagent, such as Cl(CH3)2SiC18H37 is reacted with the silanol to form a silyl ether (–Si-O-Si-). The bulk of the C18 group prevents bonding to all of the exposed silanols. This results in a surface that looks much like that on the left side of Figure 1, where there is a fairly high population of unbounded silanols, often termed “residual silanols.” The residual silanols are somewhat acidic and can be overly reactive with sample components, especially basic analytes, so it is preferable to reduce the population of residual silanols.
Is This Answer Correct ? | 0 Yes | 0 No |
Answer / vinod kumar uppalli
The SI-OH functional groups tend to ionize at at higher pH into negatively charged group. This will lead to secondary interaction between Si-O negative and basic analytes. This leads to tailing of peak, to overcome from this issue columns are end capped.
Is This Answer Correct ? | 0 Yes | 0 No |
a bottle of concerntrated HCL (36.5) was labelled as 37% (w/w) and density 1.19m/l.What is hcl molarity?
Which is the highly polar and highly non polar column in HPLC?
what is the difference b/w water content & moisture content
what is relationship between absorption and transmittance in u.v.?
Why are EDTA used to etimation of Ca,Mg etc, in Water analysis?
For Recent draft guidelines for Dissolution test apparatus calibration, why removing the salicylate tables?
How to calculate mass balance in RS after degradation
In my analysis by HPLC,In sample main peak and placebo peak are eluting with shorter resolution ( almost look like doublet). how can i get max resolution ? Is changing gradient method is usefull?
i want model written test paper for the post of analyst in IOCL(indian oil corporation ltd) any one pls help me
how require to set assay concentration for standard and sample?
why should we calibrate pH meter with 4,9.2 and 7.4 buffers particularly?
What is the difference between chromatographic purity and related substances?