Agilent 7694 Headspace Autosampler, 40 ~ 200°C, HP Agilent (CAT#: STEM-CPO-0020-LGZ)

The Headspace Sampler is a GC autosampler accessory used to introduce volatiles from liquid or solid samples into a gas chromatograph. This analytical technique is called "static headspace gas chromatography". The term "headspace" refers to the space above a liquid or solid sample that you place in a sealed vial. The term "static" refers to the fact that the volatiles in the headspace of the vial are in equilibrium with the same compounds in the liquid or solid sample.

The instrument extracts a repeatable volume of headspace and injects it into the carrier gas flowing into the gas chromatograph. Food, packaging, medicinal products, soil and water are frequently tested to determine whether they meet quality or regulatory standards. Analysis of fragrances and consumer products uses headspace to understand their composition. Forensic labs determine whether drivers are legally intoxicated by measuring levels of ethanol in human blood.

The ease with which a sample forms an air headspace depends on the "division factor" of the sample. See "Development Methods" on page 68 for a more detailed explanation. After a programmed heating time, the headspace gas is extracted from the vial and injected into a gas chromatograph for analysis.

We offer a fully refurbished spec HP Angel 7694 Headspace Autosampler with multiple units in stock. These are recertified to specification and shipped with full warranty. Installation is available upon request.

The 7694 Headspace Sampler provides an automated method to run up to 44 samples continuously without operator attention. It is compatible with HP 5890 series gc and Agilent 6890 series gc. The sampler's microprocessor optimizes the timing of each run based on operator-entered values. Up to four different methods can be stored and used to analyze a range of samples.

The unit consists of an oven and heating zone, the oven contains a circular aluminium sample carousel that can hold 6 sample vials of 10 or 20 ml. There are three heating zones. They are the vial oven, loop and transfer line.

The vial oven is where the vials are heated during the thermal and chemical stabilization process. The set temperature range is between 40°C and 200°C. At this point, the needle has not yet penetrated the nasal septum. The loop zone controls the temperature of the upper chamber, valve and sample loop. The setpoint range of the loop is between 50°C and 200°C. For most operations, it is recommended that the cycle temperature be kept 15°C above the bottle temperature.

The vial tray for 44 samples is located at the top of the unit on the left side of the oven. The tray consists of a flexible strip with dividers for each vial compartment. Tray rotation is controlled via the keyboard to assist in filling the tray with headspace vials. The tray can be moved forward and backward. A robotic arm moves samples from the vial tray to the oven and back again.

The vial is lifted out of the tray, passed through the unit until centered above the oven port, and placed into place. The rails that support the robotic arms swing to allow access to the oven.

Sampling system

Basic components include 316 stainless steel single hole (side hole) coaxial vial sampling needle or probe, 0.5 mm inner diameter, 316-SS six-port valve, nickel valve sampling circuit, a set of two micro solenoid valves, and nickel tubing. You can set the system temperature to 200°C

Principle of Operation

General operation
When the instrument is turned on, the sampler moves the first vial into position. (For models with a tray, the vial tray moves to the home position, placing the vial in position 1 next to the robotic arm. For models without a tray (G1883), the conveyor belt moves vial 1 to the home position. The oven, sample loop and The transfer line begins to heat up to reach the setpoint. Until the oven, sample loop and transfer line setpoints are reached, the display reads 7694 Not Ready and the red "Not Ready" light comes on. If pressed before the machine is ready Start/stop, the display shows as waiting to be ready, the "Not Ready" light flashes. When the set value is reached, the display changes to 7694 Ready, and the "Not Ready" light goes out.

During normal operation, the "Not Ready" light may illuminate while a run is in progress, depending on the values ​​specified by the GC cycle time and bottle equilibration time. When the "Not Ready" light is on, it simply means that the headspace sampler is not ready to insert the next vial into the oven due to time constraints to maintain a constant heating time.

Condition: certified pre-owned

Holds six 10 or 20 ml sample vials.
The set temperature range is between 40°C and 200°C.
44-sample vial tray.
A robotic arm moves samples from the vial tray to the oven and back again.
You can set the system temperature to 200°C.

Agilent G1888 Network Headspace Sampler, Transfer Line 50 °C to 250 °C, HP Agilent (CAT#-STEM-CPO-0021-LGZ)