title: Butylated hydroxytoluene can protect polyunsaturated fatty acids in dried blood spots from degradation for up to 8 weeks at room temperature.
abstract: BACKGROUND
  Dried blood spots (DBS) from fingertip prick blood can enable high throughput fatty acid profiling but may be prone to lipid peroxidation during storage. The use of butylated hydroxytoluene (BHT) on chromatography paper can prevent polyunsaturated fatty acid (PUFA) loss but examinations on the length of storage times possible are not comprehensive.
  
  
  METHODS
  In the first study, venous whole blood was saturated on paper strips pre-soaked with 0, 2.5 or 5.0 mg/mL BHT and exposed to air for up to 28 days. In a second study, the effect of sealing DBS on 5.0 mg/mL BHT-soaked chromatography strips in capped test tubes or vacuum sealed polypropylene bags with and without nitrogen purging was examined over eight weeks. The fatty acid composition of the DBS were determined by gas chromatography and the effect of sample storage on omega-3 biomarkers were examined.
  
  
  RESULTS
  PUFA and omega-3 biomarkers in DBS stored without BHT were dramatically reduced by day 3. In general, BHT delayed decreases in eicosapentaenoic + docosahexaenoic acid from baseline (3.2 ± 0.2 wt%) to 28 days (2.6 ± 0.03 wt%) of storage. In the % n-3 highly unsaturated fatty acids (HUFA) in total HUFA biomarker, BHT was more effective at preventing changes, particularly with 5.0 mg/mL BHT where no differences were detected up to 28 days. Sealed storage with BHT tended to increase the stability of the PUFA in DBS and nitrogen purging did not appear to provide additional benefits. The % n-3 HUFA in total HUFA biomarker also appeared to be more stable in the sealed storage study.
  
  
  CONCLUSIONS
  The storage of DBS in sealed containers with BHT may prevent PUFA degradation for up to 8 weeks. The % n-3 HUFA in total HUFA biomarker appears to provide a more consistent assessment of omega-3 status throughout storage as compared with other omega-3 blood biomarkers.
authors: Department of Kinesiology, University of Waterloo, 200 University Avenue West, N2L 3G1, Waterloo, Ontario, Canada.
authors: Adam H
authors: AH
authors: Metherel
authors: Ryan C
authors: RC
authors: Hogg
authors: Lindy M
authors: LM
authors: Buzikievich
authors: Ken D
authors: KD
authors: Stark
mesh_terms: D015415:Biomarkers / Q000032:analysis; D002084:Butylated Hydroxytoluene / Q000737:chemistry*; D002849:Chromatography, Gas; D004281:Docosahexaenoic Acids / Q000032:analysis*; D059788:Dried Blood Spot Testing / Q000592:standards*; D015118:Eicosapentaenoic Acid / Q000032:analysis*; D006801:Humans; D008297:Male; D010084:Oxidation-Reduction
chemical_list: D015415:Biomarkers; D002084:Butylated Hydroxytoluene; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid