Van der Walt, J.G.Procos, J.Hunter, GaelBigalke, R.D.Cameron, Colin McKenzieGilchrist, Frances M.C.Morren, A.J.Verster, Anna J.M.Verwoerd, Daniel WynandWalker, Jane B.Steyn, P.J.J.2016-03-152016-03-1520161981Van der Walt, JG, Hunter, G & Procos, J 1981, 'A rapid quantitative colorimetric determination of blood acetone applied to the assessment of ketosis in fasted pregnant ewes’, Onderstepoort Journal of Veterinary Research, vol. 48, no. 1, pp. 15-18.0330-2465http://hdl.handle.net/2263/51832The articles have been scanned in colour with a HP Scanjet 5590; 600dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.A simple, accurate, colorimetric method for determining blood acetone as an adjunct to the enzymic method of estimating the other ketones was developed and tested on a group of fasted pregnant ewes. Acetone reacted with 2-hydroxybenzaldehyde to form a stable coloured complex that followed Beer's Law up to an acetone concentration of at least 4 mg/ 100 ml of the test solution at 490 nm. While the optimum incubation time of the reaction mixture was found to be 3 h at 40 °C, it could also be left to incubate overnight at room temperature. When tested in a blood matrix, the method gave a mean within-batch coefficient of variation of 0,7%, and a day to day variation of 0, 3 – 1,2 %, while an overall recovery of 100,6 ± 1,4% was achieved over 5 concentration ranges (2,86 - 10,53 mg/100ml). The values obtained from this method corresponded closely to those from the diffusion technique previously employed and it considerably simplified the procedure. A direct linear relationship, y= 2,594x + 2,917 with a coefficient of determination r²= 0,958 for 49 pairs of data, was found between the acetone (= x mg/100 ml) and total ketone (= y mg/100 ml) concentrations in blood samples drawn from fasted pregnant sheep. This relationship can therefore be used to estimate accurately the degree of ketosis from the blood acetone concentration alone.en©ARC - Onderstepoort and Faculty of Veterinary Science, University of Pretoria (original). ©University of Pretoria. Dept. of Library Services (digital).Veterinary medicineVeterinary medicine -- South AfricaArticle