Solid phase extraction ( is it economical ? )

[eight2015]

Hi Guys, I am not talking from a company point of view ( those people are rich and don't care about money ). We have a project in our lab it will take around 8 months to 1.5 years. It is about extracting some organic compound from a biological sample.

I may use LLE , and solid liquid extraction ( if we have solid sample ). But I really know that solid phase extraction is the best but I feel it is very expensive. I only used it once during my diploma study.

Imagine I am working 8 months ( not in a company ) and you suggest to me this SPE , the cartridge is very expensive, I may use hundreds of these because may be we need one cartridge for one sample, is it true ?

Is there is any an economical way of using SPE that i don't know , like way of washing the cartridge and reuse it again and again ( with biological sample, sea water samples, waste water samples etc ). OR just use one for one sample >>>>>> thats extremely expensive if one cartiridge by one sample

Please help me, give your suggestion, what you do in your lab ( is there is other efficient extraction and an economical way other than LLE and solid liquid extraction)?. I maybe have misconception about the price etc not sure and dont know


https://www.youtube.com/watch?v=5Q20QuQaMYI

[rb6banjo]

They should not be used twice. The C18's that I use cost about $3.46 (US dollars) per sample. I see about $488 for a 4-liter bottle of hexane on the VWR website. How much does it cost you to dispose of the solvent waste? That needs to be weighed in your discussion. The SPE tubes can be used with minimal amounts of solvents. It's a trade-off, that's for sure. SPE is awesome but as you say, I work for a company and we worry more about the cost of solvent handling than a few bucks on an SPE cartridge.

[Steve Reimer]

When we ran the cost analysis 10 years ago, the cost of waste disposal was greater than the cost to buy solvents and the biggest cost was in lab overhead and salaries.
The cheapest preps we do are micro scale solvent extractions (<5mL of solvent). If those don't meet our needs we do extractions with SPE discs.

[pacerlaser]

They should not be used twice. The C18's that I use cost about $3.46 (US dollars) per sample. I see about $488 for a 4-liter bottle of hexane on the VWR website. How much does it cost you to dispose of the solvent waste? That needs to be weighed in your discussion. The SPE tubes can be used with minimal amounts of solvents. It's a trade-off, that's for sure. SPE is awesome but as you say, I work for a company and we worry more about the cost of solvent handling than a few bucks on an SPE cartridge.

Would you mind sharing who you are using for your C18s? I spent a few hours today looking for cheaper disc costs and the lowest I could find was CPI International at $5.65 per C18 disk. Most of them fall between the 7-12 dollar range. I've used Restek discs at $7.62 with excellent results but we are looking to find ones that are a bit cheaper than that.

[rb6banjo]

Sure. Generally, I don't extract liters of sample so I don't need to use the disks.

I use the ENVI-18, 500 mg/6 mL tubes from Sigma-Aldrich. Here's the link to the product number.

http://www.sigmaaldrich.com/catalog/pro ... &region=US

The Sigma-Aldrich version of what you're talking about is also about $7.45 per analysis:

http://www.sigmaaldrich.com/catalog/pro ... &region=US

If you have to extract liters of sample, then you're probably stuck with the disk costs. Do you really have to extract liters of your sample? Could something like the 500 mg/6 mL tubes work for you? What are your analytes and in what matrix?

[pacerlaser]

Currently we are using 1 L of a water sample and concentrating down to 1 mL. So far we have had good luck with using SPE for PCBs by SW8082 and DRO by SW8015. Unfortunately, I'd like to stick with the 1 L sample size because that way it won't affect our reporting limits. I think I may have found some C18 disks by Environmental Express that are quite cost effective that I might try out.

[rb6banjo]

With that sample size, I'd use the disks too. Good luck.

[twranger]

As to the original post, we need to define "biological sample" and what analytes you are looking for. For complex matrices, it seems the QuEChERS concept is working well, with included sample cleanup. This means you are putting the extraction media into the sample, and pulling out what you want.
Solid phase disks/cartridges work well with clean water samples, but heavy dirt or other organics just clogs them up. It is not an economical technique, but gets the job done fast with less solvent.

[James_Ball]

The biggest thing to consider when deciding if the 500mg sorbent tubes would be enough for a 1L sample size is how much analyte you are trying to capture. If you are in low ppb concentrations then it would be plenty. We use similar cartridges to process 1L drinking water samples. For waste water samples you would need more sorbent or use large disks. I have normally found the cartridges to give better recoveries than the disks for most usages.

When you figure in the 100-300ml of solvent that can be consumed in a normal liquid liquid extraction, it easily pays for doing SPE in solvent savings alone.

[PeakDetector]

Waters is having a sale. 50% off there new SPE plate, Oasis PRiME HLB. Its like their HLB plate but there is no need to condition the wells first. Saves time. And 50% off!!!!