The use of potassium dichromate and ethyl alcohol as blood preservatives for analysis of organochlorine contaminants.
The "gold standard" for preserving and shipping of human tissue samples for analysis of organochlorine contaminants is freezing. This method can be difficult, costly if using heavy dry ice for shipping, and often unfeasible, especially in less developed countries where electricity and dry ice are frequently rare or absent. Therefore, it is essential that more convenient and practical methods for preservation of blood samples are found. As an alternative to freezing, there have been studies employing potassium dichromate as a preservative for human or cow's milk or ethyl alcohol preservation of blood for dioxin analysis. In this study, four methods were compared to investigate the effectiveness of ethyl alcohol and potassium dichromate as blood preservatives for analysis of dioxins, dibenzofuran, and polychlorinated biphenyl (PCB) congeners. Samples of whole blood from a Dallas, Texas hospital were collected and pooled. Freezing, ethyl alcohol in two concentrations (20% and 40% per volume of sample), and potassium dichromate were used for blood preservation. The blood samples containing potassium dichromate or ethyl alcohol were stored and sent to ERGO laboratory for dioxin analysis and comparison with results from the frozen sample, which was kept frozen at all times until analyzed. This study suggests that potassium dichromate is a suitable alternative to freezing for preservation of whole blood for dioxin, dibenzofuran, and PCB measurements when either lipid or wet weight based results are reported. Potassium dichromate tablets were very easy and convenient to use--two 100 mg tablets (with a dichromate content of about 33 mg each) were added to each bottle containing 65 ml of blood. However, ethyl alcohol at 20% and 40% concentration under the conditions of this pilot study and the analytical method employed did not appear to provide satisfactory preservation when lipid based results are given or when the fat content has to be determined (wet or whole weight). Further research with a larger number of samples, inclusion also of other groups of persistent organic pollutants such as organochlorine pesticides or brominated flame retardants, a longer duration of storage time, and at temperatures greater than US or German room temperature is indicated in order to recommend the routine use of potassium dichromate as preservative for whole blood intended for dioxin, dibenzofuran, and PCB analysis.
University of Texas, School of Public Health, Dallas Campus, 5323 Harry Hines Boulevard, V8.112, Dallas, TX 75390-9128, USA. arnold.schecter@utsouthwestern.edu
Arnold
A
Schecter
Marian
M
Pavuk
Olaf
O
Päpke
Rainer
R
Malisch
D001793:Blood Preservation / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D015925:Cryopreservation / Q000379:methods*; D000431:Ethanol / Q000737:chemistry*; D006801:Humans; D006843:Hydrocarbons, Chlorinated / Q000097:blood*; D008055:Lipids / Q000097:blood; D013058:Mass Spectrometry; D011192:Potassium Dichromate / Q000737:chemistry*
D006843:Hydrocarbons, Chlorinated; D008055:Lipids; D000431:Ethanol; D011192:Potassium Dichromate