columns

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mohd
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columns

hi
can u tell what is the difference b/w symetry c18 column.
                                 &
a simple c18 column

Dr. Analytical
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A Symmetry C18 column is a

A Symmetry C18 column is a reversed phase column produced by Waters.  Every company prepares the column in a different way, but all C18 columns have the 18 carbon chain attached to the surface.  So, all C18 colums provide reversed phase retention for neutral, non-polar compounds.

However, because of differences in bonding chemistry and silica, there are some differences between C18 columns from different suppliers when you are analyzing some compound classes, like nitrogen bases.

There is no "simple C18 column."  They are all unique.  For simple organics the differences are very small, but for special separations, one C18 column can produce good results while another C18 column from a different supplier can provide bad results.  You must always evaluate your results carefully when you change columns.

mohd
mohd's picture
no my question is not this

no my question is not this
my question is why it is known as c18

mohd
mohd's picture
no why it is known as symetry

no why it is known as symetry c18

Dr. Analytical
Dr. Analytical's picture
"Symmetry" is simply the

"Symmetry" is simply the brand name for this column.  It has no scientific meaning.