Entech Instruments, Inc. products

An elegant solution for Thermal Desorption Tube screening and analysis by GCMS. The analysis of adsorbent tubes can be a nightmare for analytical laboratories, especially when there is a requirement to get results on 100% of the tubes tested. Instrument problems, unexpected analyte loading outside of the GCMS calibrated range, and cross-contamination make the normal “one-shot” analysis very risky. Even attempting to recover a “split” fraction of the tube sample onto another tube is plagued with problems such as added background, poor leak-free validation, and incomplete recoveries from yet a second tube.

Canisters are cleaned for reuse by evacuating and refilling with nitrogen or zero air multiple times to completely eliminate VOCs introduced during the previous sampling. After cleaning, canisters are  left under vacuum in preparation for resampling. System pressure and vacuum readings control the evacuation and fill times for consistent batch to batch cleaning. Silonite® coated manifolds and separate fill and evacuation flow paths ensure the most rapid elimination of VOCs and SVOCs possible. These updated systems now include method control of oven temperatures and adaptive feedback and control of the molecular drag pump to improve pump performance and longevity.

The 7200 Preconcentrator represents the next generation in GCMS sample preparation systems for the analysis of vapor-phase volatile compounds. The 7200 takes the industry standard, 7100A’s 3-stage preconcentration and water management technology, and elevates it to a whole new level. Many of the past limitations often seen in rotary valve based devices are now eliminated by combining digital valve isolation control with advanced robotic autosamplers, dropping the potential for carryover and cross-contamination far below previously obtainable levels.

The 1900 Multi-Channel Canister Sampler is Entech’s next generation solution for collecting air samples in Silonite™ coated canisters for detailed analysis in the laboratory by GC/MS or GC/FID/MS. A dramatically improved flow path now creates far less potential for carryover relative to other commercially available samplers. Mass Flow Controllers and solenoid valves have been eliminated, as these contain elastomeric seals that have been shown to outgas VOC’s, making it difficult to achieve VOC free blanks down to sub-PPBv levels. Instead, the 1900 uses a unique approach to start, control, and stop the sampling process that maintains both a clean and easily serviceable sample train, ensuring years of accurate collection of time integrated canister samples.

The 7032AQ / 7032AB Autosampler automates the introduction of up to 21 MiniCans™, Bottle-Vacs™, or Tedlar® bags into the 7200 for preconcentration. The 7032A(x) is ideal for gas-phase volatiles applications where concentrations are expected to be within 0.5–200 PPBv. For higher concentrations, a loop injection valve can be added (7032AQ-L, 7032AB-L) to allow much smaller volumes to be accurately measured. With the loop injection valve installed, these autosamplers can attach directly to a GCMS without the need for preconcentration. For wider dynamic ranges in concentrations (0.05–100,000 PPBv), a 7650(x) robot is recommended to reduce exposure times to inlet lines.