• Features and advantages
• Principle and flow chart
• Conventional techniques vs. "in vial purging"
• Peltier cryo focussing of the micro-packed trap at - 35°C
• Available water traps
• Analytical performance in the mode purge-and-trap
• Option: thermal desorption up to 280°C
• Analytical performance in the mode thermal desorption
• Technical data

• ultra trac analysis of volatile organic compounds (VOCs) with detection limits in the lower ppt-range (ng/kg)
  
• best performance for the European water standard EN ISO 15680
• "in vial purging" - no glass sparkler - no blank runs - no hot water rinse

• 80 vials, 20ml; multi matrix system for liquid, solid and mixed samples (drinking water, wastewater, foil, paper, soil, flavor, cosmetics, food, spices, ...)
• one type of micro packed trap for all polar and non polar substances - no multiple beds of various sorbent materials
• integrated Peltier cryo-trap at - 35°C
  
• automatic dosing of gaseous Internal Standard
• temperature of all components in the purge-and-trap mode up to 200°C
• selectable drypurge and predesorb in the method
  
• splitflow up to 50 ml/min by a massflow controller
• for all capillary columns with an inside diameter of 0.15 to 0.53 mm
  
• OPTIONS: - cooling of the vials
                     - Thermal Desorption, stainless steel sample tubes up to 280°C
  
• high reliability by check of the system leackage rate
• control of the system reliability by: optical foam sensor, EPC, MFC
• high sample throughput with low personal costs guarantees a fast amortization of investments
• compact and reliable purge and trap system - "made in Germany"

The sophisticated concept allows for the first time - without any purge vessle - a direct purging of volatile substances from 20 ml vials, which can be filled with solid or liquid samples and optional from thermal desorption tubes. In the purge-and-trap mode, each vial is moved into a heated sample unit, where a long and a short needle penetrates the sealing septum. All volatile substances are purged and enriched in the micro-packed trap. Here the substances are froozen out by a Peltier cooler at -35°C and finally transferred by fast thermal desorption to the gas chromatograph. As the purged water is seperated from the sample in a Peltier or membrane water trap, very sensitive detectors like a mass spectrometer or a flame ionization detector can be used. By use of a sample loop additionally internal standards or regents can be added to the sample vial. After processing a sample, the needles and the watertrap are backrinsed with carrier gas, impurities and water are removed securely from the system. The inert sample pathway and the missing glass sparkler guarantees very low detection limits and nearly no carryover.

The system performance and low detection limits attainable with the VSP4000 are particularly due to the very small adsorbent volume in the micro-packed trap. In the stable trap with an outside diameter of 1/16" different adsorbents (Tenax TA, Chromosorb G HP...) can be micro-packed. All substances from US EPA 524.2 can be measured with one trap packing. The minimum thermal mass of the trap allows a fast desorption with approx. 900°C/min, whereby excellent peak forms are obtained.

With the analysis of water samples it is important to separte the purged water. According to the substances the separation can be done with differnet water trap techniques:
       •  PWT Peltier water trap: polar and non polar substances,
           working at -15°C....-25°C         
       •  MWT membrane water trap: non-polar substances, working up to 20°C
       •  none: for all substances, only for absolute dry samples, working up to 150°C

• Substances from US EPA 524.2, 2ppb in water, FID, MS
  
• Substances from US EPA 624, 2ppb in water, AED
  
• Validation of vinyl chlorid, 1ppt in water, MS, SIM
• List of measured substances (P&T)
  
• Reproducibility, 10 samples, 1 ppb
• List of measured substances in olive oil
• Analysis with internal sample loop  
  
• Article

The system can be converted from purge and trap mode to thermal desorption mode by a simple modification. This will allow the analysis of stainless steel sample tubes filled e.g. with Tenax TA, paper or by the use of 20 ml standard glass vials filled with the sample material.

The stainless steel sample tube is placed in the axis of a special stainless steel vial with the shape of a 20 ml headspace vial. During the purge process of the sample tube the carrier gas passes the sample tube upwards which is filled with Tenax at a volume of 1ml at maximum. All adsorbed substances of the Tenax are transported to the micropacked cryo-trap. The sample, all tubes and fittings are heated at a temperature of 280°C. Also substances with a higher boiling point of 280°C can be analysed with a high recovery.

The stainless steel sample tubes can be packed with leather, foil, plastics granules or the sample tubes can externally loaded.

• Alkanes C5-C16; Tenax TA tube
• Alkanes C10-C40; empty sample tube
• Megamix US EPA 524.2 on sample tube - Tenax TA
• Comparison polyethylene terephthalate, PET; new / recycled, 100mg