土壤中有机污染物检测方案

HXW ITWORKS54Lab Manager January 2009labmanager.com MAGAZINELab ManagerRunYourLab Like aBusiness January 2009 Volume 4·Number 1 Your subscription may be expiring； renew today if you haven’t already. Visit www.labmanager.com/subscribe.asp Problem：Extracting compoundsfrom various samples using tradition-al methods involves some give andtake. You can choose to use Soxhlet.which is relatively inexpensive forequipment but uses a tremendousamount of solvent and takes hoursto run. Sonication is fast， but it alsorequires copious amounts of solventand banks of individual sonicators(which also adds to the cost) if yourlab handles more than a few samplesa day. Pressurized solvent extrac-tion uses much less solvent， but onlyprocesses six samples per hour andthe equipment is costly. Solution： Microwave extraction hasbeen used for many years to extractcompounds from plastics， biologicalsamples， foods， animal feeds， paper，wastewater and many other typesof samples. In early 2008， the U.S.Environmental Protection Agency(USEPA) approved Method 3546for microwave extraction of organiccompounds from soils， sludges andsediments. It is a proven techniquethat is fast， uses significantly less sol-vent than traditional techniques andis cost-effective. With the capability to process 40samples simultaneously and a patent-ed Xpress technology that providesoptimum control for high-pressureextractions， the MARSXpressTM(CEM Corporation) microwave reac- Extraction System tion system provides a fast， reliableplatform for busy analytical labora-tories， allowing 80 extractions andfiltrations to be performed in lessthan four hours. The system uses 90percent less solvent than Soxhlet，making it a much more environmen-tally friendly technique. The advanced technology of theMARSXpress system makes it re-markably easy to use. The IR temper-ature sensors and the advanced designof the MARSXpress vessels allowthe system to accurately measure theinternal temperature of each vesselvirtually instantaneously. The dual，NIST-traceable， calibrated tem-perature system provides unmatchedcontrol that you can rely on for theextraction results you need.First， the sample is weighed into a patented MARSXpress vessel and solvent is added. Microwave extrac-tion is much more efficient than othermethods， so you use significantly lesssolvent than with other techniques.The vessel is then capped and loadedinto the carousel. The MARSXpressvessel features a simple screw-oncap and does not require the use ofspecial tools. The carousel is thenplaced in the microwave， the ap-propriate method is loaded and thesystem is started. The MARSXpresscomes with a pre-loaded library ofUSEPA-approved methods， thoughyou can always program your own.Finally， the “start”button is pressedand your extractions are under way.It’s that simple. The SynergyPrepTMsoftware displays and records tem-perature readings for all the vessels，so you will know for certain how welleach sample performed. This is espe-cially helpful when running samplesfrom different sources on the samecarousel. Chemists in busy testing labs needaccurate， dependable results in atimely manner. The MARSXpresssystem provides those results witha method that can help significantlyreduce solvent usage and is also cost-effective. For more information， go toWww.cem.com.