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The United States Pharmacopoeia (USP) has classified HPLC columns by L# types. [20] The most popular column in this classification is an octadecyl carbon chain (C18)-bonded silica (USP classification L1). [21] This is followed by C8-bonded silica (L7), pure silica (L3), cyano-bonded silica (CN) (L10) and phenyl-bonded silica (L11).
A monolithic HPLC column, or monolithic column, is a column used in high-performance liquid chromatography (HPLC). The internal structure of the monolithic column is created in such a way that many channels form inside the column. The material inside the column which separates the channels can be porous and functionalized.
It determines the quantity of analyte that can be loaded onto the column. Larger diameter columns are usually seen in preparative applications, such as the purification of a drug product for later use. [46] Low-ID columns have improved sensitivity and lower solvent consumption in the recent ultra-high performance liquid chromatography (UHPLC). [47]
Another important feature of the hydride-based phases is that for many analyses it is usually not necessary to use a high pH mobile phase to analyze polar compounds such as bases. The aqueous component of the mobile phase usually contains from 0.1 to 0.5% formic or acetic acid, which is compatible with detector techniques that include mass ...
C18, an octadecyl-type hydrocarbon with 18 carbon atoms, such as Fatty acids such as Stearic acid, C 18 H 36 O 2; Oleic acid C 18 H 34 O 2; C18 bonded silica stationary phase column, a type of reversed-phase chromatography column; IEC 60320 C18, a power connector; Colorectal cancer (ICD-10 code)
Typically the second column has a different separation mechanism, so that bands that are poorly resolved from the first column may be completely separated in the second column. (For instance, a C18 reversed-phase chromatography column may be followed by a phenyl column.) Alternately, the two columns might run at different temperatures.
Waters Corporation is an American publicly traded analytical laboratory instrument and software company headquartered in Milford, Massachusetts.The company employs more than 7,800 [2] people, with manufacturing facilities located in Milford, Taunton, Massachusetts; Wexford, Ireland and Wilmslow, [3] Cheshire.
End-capped columns have much lower residual silanol group activity compared to non-endcapped columns. [1] Endcapped columns show decreased retention for hydrogen bond acceptors, such as ionized bases, and increased retention for protonated bases.