Chromatography Forum

Good day.
I AM LOOKING FOR A METHODOLOGY FOR DOSAGE PVA'M DOING TESTING METHOD IN WHICH IS USED RID DETECTOR AM USING SODIUM NITRATE 0.1M ANY EXPERIENCE WITH THIS METHOD OR OTHER WOULD BE VERY GRATEFUL TO KNOW ME DO IT THANK YOU.
ATTE.
CARLOS

Sample preparation
PVA was dissolved in the mobile phase
(concentration 0.1 %)
Column
3 × PL aquagel-OH 30 in series, 7.5 × 300
mm, 8 μm (Agilent p/n 79911GF-MXA) in
series with PL aquagel-OH 30, 7.5 × 300
mm, 8 μm (Agilent p/n 79911GF-083)
Mobile phase
0.2 M NaN0H3, NaH2P04, pH 7
Flow rate
1 mL/min
Column compartment temperature
25 ° C
Injection volume
100 μl
Detector
Refractive index detector
Polymer standards
Polyethylene oxide EasyCal standards in
vials for calibration (Agilent p/n 5064-
8280)
Just a little bit Google and you will find much more application notes on the web. Good luck.

Dear Gerhard Kratz.
Thank you for giving such information'm doing the requirement of the column to test the method that hast sent me.
My problem ophthalmic solution of polyvinyl alcohol is as follows.
The method we used is ultraviolet (uv) (dosage), the% newly manufactured product is 100%, but after 6 months, the dosage is lowered to approximately 50% compared to baseline; then we are trying to find a method that guarantees an exact result, to rule that our product is a degraded or that the method we are using is not very accurate. If you had any experience and / or information would be very grateful.
Atte.
carloss

Did you use partially or fully hydrolyzed PVA? At what temperature you stored the samples?
Is there another alcohol in your formulation?
No quantitative method is available for the determination of PVA although, various methods have been
described for the detection of PVA. Filter paper treated with potassium iodide and iodine solutions has
been suggested for measuring Polyvinyl alcohol concentration in wastewater in a concentration range of
1000-20,000 mg/l. the color of polymers, including Polyvinyl alcohol, and their derivatives in various
solvents have been used to identify them. The green complex formed by reaction of polyvinyl alcohol with
boric acid has been used to detect small amounts in polyvinyl chloride resins.
Run a UV spectrum to find the optimum wavelength. Maybe 280nm will be a good one.
Degradation is very much dependent on the temperature. At 20°C for 6 months 50% loss is not unusual.
Wash your column after use with 100% water. In my opinion it is difficult to measure PVA on an SEC column due to its MW distribution.
MAybe a special column for alcohols, an IEX column, will give you better results. Good luck.