Synergi HPLC Columns

Chromatography is the separation of components in a mixture based on their chemical nature. Chromatography can be performed in either liquid (HPLC) or gas (GC) forms. Liquid chromatography, specifically High Pressure Liquid Chromatography (HPLC), involves a stationary phase (sorbent), a mobile phase (liquid) and the analyte or compounds of interest. Analytes or compounds of interest are injected onto an HPLC column (packed with sorbent that contains a variety of chemistries) in mobile phase. As the mobile phase, which is carrying the analyte or compounds of interest, travels across the stationary phase, the analyte or compounds of interest separate from each other as they interact with the stationary phase, each eluting from the column at various times. Gas chromatography (GC) is similar to HPLC in that is utilized with working analytes or compounds of interest that can be vaporized without decomposing. In GC, gas is used instead of a liquid (like in HPLC). As analytes or compounds of interest travel in the gas mobile phase and interact with the stationary phase, eluting at various times.

Using high pH mobile phase, the retention of polar bases will be increased. Signal response does depend upon ionization state, so if we use high pH, we are actually de-ionizing our bases and should lose sensitivity. But this doesn’t happen actually. When we increase the retention of the polar base analytes using high pH, it elutes later in the gradient run and in a high percentage of organic (acetonitrile or methanol). For example, when using formic acid, the polar base analyte peak is eluting in about 5-10% acetonitrile, but when we switch to pH 10, the polar base analyte peak is coming off in about 30-40% acetonitrile. The increased % of acetonitrile in the source is what allows the ions to be ionized thoroughly, thereby giving you a better response in ESI-MS.

When using a gradient method, no change may be made to particle size or column dimensions. They must be the same as those directed in the monograph.

In general, a column with polar selectivity, such as Synergi Fusion-RP or Kinetex Biphenyl, will preform well for pesticide/herbicide screens using LC/MS/MS.