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- Posts: 105
- Joined: Sat Feb 02, 2008 12:35 am
We are developing a GRO method by head space ( G1888) technique in soils.
The matrix modifier solution is NaCL ( 180g/500mL water) according to EPA 5021. The blank soil is a sample baked to 400°C we use for QC purposes, so far, so good. But when we spiked GRO standard in real samples the recovery dropped to 50% over and over again.
The G1888's parameters are:
*Vial size=20mL
* Sample=2gr
*Modifier=10mL
* Vial press= 102Kpa
* Carrier press=103Kpa
*Oven=85°C
*Loop=90°C
*Transfer line=100°C
*Vial equilb=50min.
*Press. time=0.6min.
*loop fill=0.5min
*loop equilib=0.05min
*Injection time=1min.
*Shake=high.
Any suggestions?
Best regards.