About The Technique
The 7000HT has a self-contained microprocessor and operates with any GC giving you maximum flexibility in your lab. The 7000HT offers sample mixing for fast equilibration times, constant heat time for unmatched sample reproducibility and throughput, complete method optimization mode and sample temperatures to 200oC. The 7000HT Headspace Analyzer has 50 vial positions.
With the 7000HT, chromatographic run time determines the analysis time when used in Constant Heat Time mode. The microprocessor automatically determines when to load and unload samples to and from the 12-position platen heater. Constant Heat Time ensures that each sample is heated for exactly the same amount of time and that no time is wasted waiting for samples to equilibrate. Constant Heat time not only speeds up the analysis but also improves precision.
OPTIMIXTM Sample Mixing
OPTIMIXTM is a sample missing system allowing the user to speed up sample equilibrium time in liquid samples. OPTIMIX offers 9 power levels to select from. By agitating liquid samples, equilibrium times are reduced and more samples can be analyzed in less time. OPTIMIX reduces thermal exposure of the sample thus reducing possible breakdown of the analyte.
Method Optimization Mode
In Method Optimization Mode the 7000HT analyzes a series of standards, automatically incrementing any time or temperature parameter. Important parameters include equilibration time; equilibration temperature, mixing time, and loop fill time. The 7000HT, with its 50 sample positions, combined with method optimization allows almost complete method optimization overnight.
The 7000HT sample path can be heated up to 300oC. This feature eliminates problems with carryover of many analytes. With a valve and loop system you change the sampling volume by changing the loop. With the valve and loop system running samples that have a higher vial pressure than the column head pressure is not a problem as it is with pressure-balanced systems.
The temperature and pressure conditions are precisely repeated for each sample; this includes the ample equilibration time for each sample. Tekmar's valve and loop sampling technique provides for exceptional reproducibility, typically better than 1% relative standard deviation.