Journal of Dairy Science Vol. 22 No. 7 501-511
© 1939 by American Dairy Science Association ®
The Determination of Blood Plasma Carotene in the Bovine using a Photoelectric Colorimeter1
L. A. Moore
Michigan Agricultural Experiment Station, East Lansing, Michigan
ABSTRACT
- A simple phase separation of carotene from bovine plasma has been outlined.
- When petroleum ether is used as the solvent the boiling point and temperature of extraction are important factors in the amount of carotene extracted.
- When petroleum ether with a boiling point of 73–76° C. was used and the extraction carried out at 10–12° C. the epiphase gave true carotene values.
- When the phase separation method is used, the relationship of the amount of carotene in the epiphase to the total amount present in the sample should be established.
- The temperature at time of pipetting into the absorption cell under ordinary laboratory conditions had no measurable effect on the galvanometer readings.
- The use of 15 ml. of a 95 per cent ethyl alcohol for precipitation of the proteins from 10 ml. of plasma was found to be advantageous.
- Shaking the tubes for two to three minute periods gave more consistent results than shaking for one minute.
- The addition of 0.5 ml. of alcohol to destroy emulsions had no effect on the determination.
- The method was shown to give consistent results from day to day.
- Plasma stored at 2.0° C. showed no loss of carotene over a period of three weeks.
- The use of the phase separation method in conjunction with the photoelectric colorimeter offers a simple and rapid procedure for the determination of carotene in bovine blood plasma.
FOOTNOTES
1 Journal Article No. 344 (N.S.) Michigan Agricultural Experiment Station. From a portion of a thesis presented to the Graduate of School of Michigan State College in partial fulfillment for the Ph.D. degree.
Copyright © 1939 by the American Dairy Science Association ®.