Solved: Sand for Method Blanks

Discussions about sample preparation: extraction, cleanup, derivatization, etc.

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Ottowa Sand 20-30 mesh (Fisher# S23-3) is commonly used as a medium for method blanks and spiked method blanks. I routinely used it for metals analysis.
I am starting to use it as 'soil' matrix for 8260-VOC and 8015-DRO method blanks.

My bottle has a pretty big spike that elutes just beyond the o-terphenyl peak on my HP-5ms column and it amounts to about 15 ppm. This is ruining my DRO by FID detection limit. Baking out a peak that heavy would require a furnace which I don't have.

Does anybody else see this peak?

Fisher offers another quartz sand, Fisher#AC370940050 40-100 mesh. But I do not know how clean this sand might be for use in method blanks.

Reporting back on this issue...

I've soxlet extracted the Ottowa Sand with 1:1 hexane:acetone. This completely removed the extra peak next to the o-terphenyl.
Can you do an extraction with DCM on it? Either a soxhlet or pressurize fluid extraction should remove the offending compound. While it hasn't been a problem for VOAs, baking sand at 450 degrees C overnight can create active sites on the sand, so we gave up on trying to bake it clean and just solvent extract then dry at ~100 degrees.
For VOA blank matrix the sand can be washed with water and stored at 100 degrees for reuse.
Steve Reimer wrote:
Can you do an extraction with DCM on it? Either a soxhlet or pressurize fluid extraction should remove the offending compound. While it hasn't been a problem for VOAs, baking sand at 450 degrees C overnight can create active sites on the sand, so we gave up on trying to bake it clean and just solvent extract then dry at ~100 degrees.
For VOA blank matrix the sand can be washed with water and stored at 100 degrees for reuse.
I'm gonna go with the soxlet idea and just take a day to run several batches of sand through the same setup. Good to know about the VOA suggestion; thanks.
Steve Reimer wrote:
Can you do an extraction with DCM on it? Either a soxhlet or pressurize fluid extraction should remove the offending compound. While it hasn't been a problem for VOAs, baking sand at 450 degrees C overnight can create active sites on the sand, so we gave up on trying to bake it clean and just solvent extract then dry at ~100 degrees.
For VOA blank matrix the sand can be washed with water and stored at 100 degrees for reuse.


Exactly what we do for both.

For Metals analysis we use teflon boiling chips to avoid any contamination of boron, silica and sodium which can be extracted from the sand.
The past is there to guide us into the future, not to dwell in.
3M Empore Filter Aid 400 Microglass beads
Has anyone tried using this material for method blank media?
LALman wrote:
Steve Reimer wrote:
Can you do an extraction with DCM on it? Either a soxhlet or pressurize fluid extraction should remove the offending compound. While it hasn't been a problem for VOAs, baking sand at 450 degrees C overnight can create active sites on the sand, so we gave up on trying to bake it clean and just solvent extract then dry at ~100 degrees.
For VOA blank matrix the sand can be washed with water and stored at 100 degrees for reuse.
I'm gonna go with the soxlet idea and just take a day to run several batches of sand through the same setup. Good to know about the VOA suggestion; thanks.

Well, I did not want to use DCM and did the soxlet extraction for a whole day with hexane while I was doing Oil and Grease extractions. The peak is still there giving me a 20 ppm blank.

It must be that the acetone in the o-terpenyl spike is helping extract it. I'm going to try acetone, perhaps with a little hexane. I know from experience that acetone/water can take baked on organic residue right out of microwave teflon vessels used for prepping metals.
Reporting back on this issue...

I've extracted the Ottowa Sand with 1:1 hexane:acetone. This completely removed the extra peak next to the o-terphenyl.
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