HPLC Pumps
A typical HPLC includes between 1–4 reservoirs for mobile phase solvents. The mobile phase solvents are pulled from their reservoirs by the action of one or more pumps. Shown here is a close-up […]
Image and Video Exchange
Get a look at images, photos, videos, and animations that encompass many facets of teaching and learning about analytical chemistry.
Gradient Elution Separation of Flavonoid Mixture
The illustration below shows the gradient elution separation of a mixture of flavonoids. Mobile phase A is an aqueous solution of 0.1% formic acid and mobile phase B is 0.1% formic acid […]
Using a Solvent Triangle to Optimize an HPLC Separation
One strategy for finding the best mobile phase for an HPLC separation is to use the solvent triangle, which allows us to explore a broad range of mobile phases with just seven […]
HPLC Column
The most common type of HPLC column is a stainless steel tube with an internal diameter between 2.1 mm and 4.6 mm and a length between 30 mm and 300 mm. The […]
HPLC Instrumentation
The photo below shows an example of a typical HPLC instrument with insets showing close-up views of the pumps that move the mobile phase through the system, and the plumbing used to inject […]
Finding the Area for Overlapping Chromatographic Peaks
In a GC analysis the area under the peak is proportional to the amount of analyte injected onto the column. The peak’s area is determined by integration, which usually is handled by […]
GC-MS
The figure below provides a block diagram of a typical gas chromatography-mass spectrometer (GC–MS) instrument. As illustrated here, a three component mixture enters the GC. When component A elutes from the column, it enters […]
Electron Capture Detector
Shown here is a schematic diagram of electron capture detector (ECD) for gas chromatography. The detector consists of a β-emitter, such as 63Ni. The emitted electrons ionize the mobile phase, which is […]
Flame Ionization Detector
The schematic diagram below shows a flame ionization detector for gas chromatography. The eluent from the column mixes with H2 and is burned in the presence of excess air. Combustion of organic […]
Thermal Conductivity Detector
One of the earliest gas chromatography detectors takes advantage of the mobile phase’s thermal conductivity. As the mobile phase exits the column it passes over a tungsten-rhenium wire filament (see figure below). […]
GC Injectors
Shown here is a schematic diagram of a heated GC injector port for use with packed columns. The needle from the syringe pierces a rubber septum and enters into the top of […]
GC Syringe
Shown here is an example of a syringe for injecting samples into a gas chromatograph. This syringe has a maximum capacity of 10 μL with graduations every 0.1 μL.