Firma:              Hewlett Packard

Modell:                         1090 II

Kommentar:     Dokumente engl.

The elements of a basic liquid chromatography (LC) system are shown in Figure 1-1. A liquid sample is taken from a mixture to be analyzed and introduced to a part of the system that is at elevated pressure. The sample is then transported to a separator by the flow in the sytem. In LC, the separator is called the column and consists in most gases of a tube filled with porous material called the stationary phase. A liquid, called the mobile phase, flows through the tube between the particles of stationary phase material.

The components in the sample become distributed differently between the mobile and stationary phases because they have different interactions (physical and chemical) with each phase. You can select the nature and strength of the interactions by your choice of phases. The components move with different speeds through the column, depending an their affinity for the different phases, and so they elute from the column at different times: their retention times. By changing the composition of the mobile phase during the elution, a gradient analysis, it is possible to analyze a wider variety of compounds in a given time than would be possible under constant conditions.

After the separator, or separators, the column effluent enters the detector, which measures a physical or chemical property of each, now relatively pure, compound and creates a proportional electronic signal. By calibrating with a standard mixture of known compounds, the nature of the compound in the mixture can be elucidated. The quantity of the relevant compounds in the mixture can be calculated by integration of the signal.

Choosing a suitable place

Temperature                        5 - 40°C (40 - 104° F)

Humidity                              < 95% (non-condensing)

Line voltage                         100 - 120 VAC +5%, -10% or

                                           220 - 240 VAC +5%, -10%

Line frequency                     50 Hz (48 - 55 Hz) or

                                           60 Hz (57 - 66 Hz)

Line disturbance                   Surges and sags must not exceed ±20% of normal line voltage.    Voltage must return to normal within 20 ms.

                                           Line transients:

                                           > 10 µs pulse width and > 50% of normal rated voltage may        produce instrument malfunctions.

Power consumption              750 VAC maximum

Dimensions                   70 cm x ^- 60 cm x 52 cm

                                           (28" x 26" x 20") (width x height x depth)

Weight                         60 - 80 kg (132 - 176 lbs) depending on the configuration.

Gas Supply                   Pure helium (> 99.9%) at 0 - 0.5 bar (0 - 7.5 psi)

For                              Compressed air at 5 bar (75 psi)

auto-injector                 < 10 µm filter grade.