Introduction However, they were concerned that the high molarity of the sample might cause mixing problems and result in a non-homogeneous counting situation which might cause problems in their flow counting system. Sample Volume Appearance at 20 °C 1.0 mL Clear 2.0 mL Clear 4.0 mL Clear 5.0 mL Clear 5.5 mL Clear 6.0 mL Clear 6.66 mL Clear 7.0 mL Clear 8.0 mL Clear 8.5 mL Clear 9.0 mL Hazy/Unstable 10.0 mL Hazy/Unstable Recommendation Discussion We prepared 3.0 M ammonium formate and buffered it to pH 4.9 with formic acid and then evaluated Ultima-Flo AF at 20 °C. The results are shown in the following table: Ultima-Flo AF will accept a maximum of 8.5 mL 3.0 M ammonium formate in 10.0 mL cocktail at 20 °C. Consequently a flow counting ratio of 2:1 (10.0 mL cocktail with 5.0 mL sample) is possible with easy, rapid and reliable mixing. PerkinElmer, Inc. 940 Winter Street Waltham, MA 02451 USA Phone: (800) 762-4000 or (+1) 203-925-4602 www.perkinelmer.com For a complete listing of our global offices, visit www.perkinelmer.com/lasoffices ©2007 PerkinElmer, Inc. All rights reserved. The PerkinElmer logo and design are registered trademarks of PerkinElmer, Inc. Ultima-Flo is a trademark of PerkinElmer, Inc. or its subsidiaries, in the United States and other countries. All other trademarks not owned by PerkinElmer, Inc. or its subsidiaries that are depicted herein are the property of their respective owners. PerkinElmer reserves the right to change this document at any time without notice and disclaims liability for editorial, pictorial or typographical errors. 007902_20 N O T E One laboratory was performing flow counting with samples of 3.0 M ammonium formate, buffered to pH 4.9 with formic acid. The laboratory requested help to select the proper safer cocktail from PerkinElmer’s Ultima-Flo™ family of flow scintillation cocktails. The researchers suggested that Ultima-Flo AF (PerkinElmer part number 6013589) might be suitable, since “AF” indicated that this cocktail had been developed for use with flow gradient systems involving ammonium formate. A P P L I C A T I O N L S C C O C K TA I L S LSC in Practice Cocktail Selection for Use with 3.0 M Ammonium Formate