By Anonymous on Saturday, April 19, 2003 - 07:26 am:
Please suggest HPLC method to find out purity of Tinuvin 622 & Chimassorb 944
By Anonymous on Saturday, April 19, 2003 - 09:39 am:
Look at google, I'm sure you will find some articles.
It's so easy:
go to your internet browser
type in the adress bar www.google.com
press the Go button
then type in your search parameters for google:
eg. Tinuvin HPLC method flow column followed by return or pressing the search button. (you can copy and paste the example)
I'm sure you will find some articles this way, but just asking is a little bit easier isn't it?
By Anonymous on Tuesday, April 22, 2003 - 12:30 am:
Thanks for suggestion but not find any suitable method on google.com & related sites.
By Anonymous on Tuesday, April 22, 2003 - 04:36 am:
Try C8 column with MeOH/buffer gradient. Experiment with 85-100% MeOH/10 mins using an acidic pH buffer of your choice.
By Tom Mizukami on Tuesday, April 22, 2003 - 05:17 pm:
I would contact the manufacture(s), they must have a purity assay. If not talk fist with some column tech support people Agilent, Waters, Phenomonex, etc. they might have an application note. These are large MW additives >3000, make sure you use an appropriate column. Good luck.
By Tom Mizukami on Tuesday, April 22, 2003 - 05:33 pm:
This method is for a Ethanox 330 a different additive, but illustrates you might need to use nonaqueous RP. The article is here: http://scholar.lib.vt.edu/theses/available/etd-72597-16125/unrestricted/ANGIE.PDF
Chromatographic Analysis. A Hewlett Packard Series 1050 HPLC was used for all extract
analysis. The mobile phase consisted of 90:5:5 (v/v/v) acetonitrile:methanol:tetrahydrofuran. A
20mL injection volume of the combined solid phase trap rinse solvent and liquid methanol trap
after reduction in volume to 1.0mL was introduced. The flow rate was set at 1.0 mL/min. The
column was an ODS Hypersil (150 x 4.6mm, 5mm dp) with a C18 (Varian, Sunnyvale, Ca.) guard
column. It was necessary to employ the use of a guard column in order to retain for longer
periods of time the performance of the separation column. UV detection at 280 nm was used for
all analyses. Other wavelengths, such as, 220 nm could have also been employed, but
quantification of the additive was more difficult at 220 nm, because of strong absorption from
interfering low molecular weight oligomers.
By Anonymous on Tuesday, April 22, 2003 - 11:19 pm:
Both are high molecular weigh (2000-4000 g/mol) oligomeric additives, indicating standard RP column (150 x 4.6mm, 5um) may not be the best choice?
I found this paper where Tinuvin 770 and Chimassorb 944 are analysed using HPLC:
Vandenburg, H.J., Clifford, A.A., Bartle, K.D., Carroll, J., Newton, I.., Garden, L.M., Dean, J.R., Costley, C.T. Analyst (1997), 122(9), 101R-115R.
Please also find Ciba's technical data sheets for solubility etc issues:
http://www.cibasc.com/adservices/doc.asp?t=tds&a=CHIMASSORB+944&b=PA%5FPlastics&c=ZZ&.pdf
http://www.cibasc.com/adservices/doc.asp?t=tds&a=TINUVIN+622&b=PA%5FPlastics&c=ZZ&.pdf
I also agree that Ciba must have an purity assay.