Waters Sep-Pak Cartridges and Plates - Manual (Page 2)

[ Care and Use ManUal ]
Sep-Pak Cartridges and Plates 2
I. IntroduCtIon
Sep-Pak devices are available in many styles to accommodate
manual and automated solid-phase extraction. Devices are available
in convenient Plus, Light, Classic, Vac, Vac RC, and 96-well plate
formats.
Available Sorbent Chemistries:
Reversed Phase: C
18
, tC
18
, C
8,
tC
2
Normal Phase: Silica, Alumina A, Alumina B, Alumina N, Florisil ®
Ion Exchange and Mixed Mode: Aminopropyl, PSA, Accell™ Plus
QMA, Accell Plus CM, Cyanopropropyl, Diol
Speciality Products: Porapak ® RDX, DNPH-Silica, XPoSure™, Ozone
Scrubber, Dry, PS2, AC2, Carbon Black/Aminopropyl
II. usInG seP-PAK CArtrIdGes And 96-WeLL PLAtes
Below is a five step guideline for using Sep-Pak cartridges. Each separation
is different and not all steps may be required for your application. Typical
strong and weak solvents used in the sample preparation steps are listed in
Table 1 below.
Table 1: Typical strong and weak solvents used in the
sample preparation.
Prepare sample: The sample can be applied to the Sep-Pak Cartridge in
either liquid or a gas phase. If the sample is a solid, it must be dissolved or
extracted prior to loading.
Condition/Equilibrate Cartridge: A conditioning step is required for
reversed-phase sorbents (e.g., C
18
). Use a strong solvent to wet the station-
ary phase. Conditioning is followed by an equilibration step using a weak
solvent.
Load Sample: The sample is loaded onto the cartridge.
Wash: The wash step removed interferences while retaining the analyte. If
weakly retained interferences are present in the sample matrix, wash with an
appropriate weak solvent.
Elute: Use an appropriate stronger solvent to elute the analyte while retain-
ing more strongly bound interferences.
III. strAteGIes For soLId-PHAse eXtrACtIon
Purification: Use as a “chemical filter” to retain the component of interest
while interferences elute, or to retain the interferences while the analyte
passes through unretained.
Trace Enrichment or Concentration: Use to concentrate an analyte from
a dilute solution. This is done when the analyte concentration is below the
detection limit of the analytical method.
Fractionation: Use with a step gradient of increasing solvent strength to
selectivity elute and isolate analytes based on differences in polarity.
Solvent Exchange: Use to adsorb the analyte and elute with a
desirable solvent. This is helpful of the sample is dissolved in a solvent
that is incompatible with the analytical method.
Separation Mode Typical Weak
Solvents
Typical Strong
Solvents
Reversed Phase Water or bufer.
May contain low
concentrations of organics,
such as methanol. Acetonitrile,
methanol, or
aqueous/organic
mixture
Normal Phase Hexane, toluene Methylene chloride,
methanol
Weak Cation
Exchange Low ionic strength
buffer, pH >4 High ionic strength
buffer, or pH <2
Strong Anion
Exchange Low ionic strength
buffer, pH <8 High ionic strength
buffer, or pH >10