VB-5 MS ?

[Olga]

Dear all,

I asked local supplier to give me the prices for DB-5 MS type column what I would like to buy. Apart DB-5 ms and BPX-5, they mentioned VB-5 MS column which would cost me ½ price of DB-5. As I understood they try to promote new product on the market, therefore the price is low.

Has anyone used this column ? It comes from Vici company, which is not actually so well known here in Europe.
Any kinds of comments are wellcome. Thanx.

[WK]

Dear Olga,
If they are really keen to sell then they will let you try one. If it works they can invoice you.
If not you can send it back.
I have not heard of them personally.

Be very aware of RT and resolution/selectivity differences between apparently similar phases.
Be aware of differences between e.g. a "5" and a "5MS".
Maybe you know this anyway?

[Olga]

Hello WK, thank you for replying

I guess your are right, that the best way to find it out is just to try it..

Dear Olga,

Be very aware of RT and resolution/selectivity differences between apparently similar phases.
Be aware of differences between e.g. a "5" and a "5MS".
Maybe you know this anyway?

Well, I don't so much between "5" and "5MS"... I am buying it for GC-MS. In old days all columns were just "5" and we used them for both FID and MS. Now they say that "5MS" is more suitable for MS, but why, actually I don't know...
However, the point is that I have DB-5 60m and DB-5 30 m columns running in 2 GC-FID's. Therefore, I would like to have the same polarity column in GC-MS which now contains OV-1701 !!
What do you think it would be the best choice then to have for GC-MS?
Do you DB-5 would match better than DB-5MS for GC-MS in this case?

[Mark]

Olga,

The DB-5MS columns are just supposed to be lower bleed versions of the DB-5 phase materail, same polarity and selectivity. I have used both and seen no differences (other than a little better bleed). They are interchangable. Actually, unless you are doing high temp work or analyzing very low level samples the usual DB-5 phases work just as well on the GC-MS.

Regards,
Mark

[xxx]

A ms column is supposed to have the lowest bleed,or lower as a normal column.
In most case a column is named ms if it has low bleed but is totally identical to a normal

In other case the chemistry of the column phase is different enough to provide a lower bleed that is the reason why db5 and db5-ms are not 100% the same.

DB5 is 5% Phenyl-methylpolysiloxane phase
DB5-ms is Phenyl-Arylen-Polymer equivalent to a DB5,although that's a little difference,this could affect selectivity...elution order

[Olga]

Mark, xxx - THANK you !

[Durk]

I know Varian sells a new family of GC columns, the VF-serie. With this type of columns the bleed is a factor four lower than its equivalents. This is only important if your temperature programming is higher than 200 °C. Besides the bleeding the life span is a factor 2 higher.

Durk