Chromatography Forum

I have water and soil samlpes and i am asked to determine BTEX in these samples i know that one possible tehinque is by SPME GC/FID but the pro i don't have any standard method or any reference to relay on could any one help me

Hi
I determine BTEX in water by HS-GC-FID. The LOD is about 0.1ug/L. If you are interested i can explain you my method.

Supelco would be glad to send you literature and offer you help if you give them an email or a free phone call.

All you have to do is ask. (and I don't work for them anymore)

Rodney George
consultant

thank u for ur reply and am intersted in having ur method

Colum: DB-624 (30 x 0.32 x 1.
Inlet: 170ºC ; split 1:10
Detector: FID 260ºC
Tª program: 40º(5min) at 10º/min to 200º(0min) at 20º/min to 240º(0min) (total: 23min)
Carrier: He
Flow: 1.5ml/min (constant)

Sample
- Vial 20ml
- 2g NaCl
- 10ml sample
- 5 ul ISTD (1-Cloropentane solution in MeOH; 8ng/ul)

Autosampler: CTC CombiPal
- Syringe Tª = 75ºC
- Incubation sample: 70ºC; 30min; agitation 500rpm.

The elution order are : benzene (tr = 9.4), ISTD (11., Toluene (12.2), Clorobenzene (14.1), etilbenzene (14.3), m and p-xylene (14.5), o-xylene (15)

m-xylene and p-xylene coelute in a 624 column. If you need diferenciate it you can use a wax column. But in a wax column the benzene elute near the MeOH.

If you need more information...
good luck

The column dimensions are 30 x 0.32 x 1.8

again and again thank u so much for ur help just one question or two first i don't have the automated autosampler with spme and i don't think this would be a problem
second the resourse of ur information is a manufaturere 's method or a standrad test method (ASTM, UOP,.......etc)
or u have take from a scintific book

Hi
The method isn't a standard method. It's developed and validated by our laboratory. We have participated in interlaboratory analysis with this method and we have obteined good results. (My method is for headspace, not for spme, but you can adaptate it)
If your injection is manual your precission will be poor.