Page 1 of 1

NOISE-SENSITIVITY ISSUE

Posted: Tue Oct 18, 2011 3:38 pm
by rc_123
We have been working on USP method for one of my products.The details are as follows.

Buffer: Dissolve 0.5 g of tetrabutylammonium hydrogen sulfate and 1.0 g of monobasic potassium phosphate in water, add 2 mL of phosphoric acid, dilute with water to 1000 mL, mix, and pass through a 0.45-µm filter.

Mobile phase—Prepare a degassed mixture of Buffer solution and methanol (18:7).

Wave length:UV 293 nm.Flow:1.2 mL/min
Column:L11-250X4.6 mm-5 micron.

We have observed very high noise using above conditions with one brand column of L11 Packing.However ,no noise was observed when using other brands of L11.Is it possible that a specific column contribute to more noise killing sensitivity of the method?Please advice.

Re: NOISE-SENSITIVITY ISSUE

Posted: Tue Oct 18, 2011 9:24 pm
by tom jupille
L11 is phenyl boded phase. Yes, some brands bleed more than others, depending on the bonding chemistry and the purity of the underlying silica.