Improvements to enhanced horseradish peroxidase detection sensitivity

Area of Science:

• Biochemistry
• Analytical Chemistry
• Biotechnology

Background:

• Enhanced chemiluminescence (ECL) reactions, particularly with horseradish peroxidase (HRP), often exhibit a lag phase before light emission at low substrate concentrations.
• This lag time and suboptimal light output can limit detection sensitivity in various biological and chemical assays.

Purpose of the Study:

• To investigate methods for eliminating the lag time in enhanced chemiluminescence reactions.
• To enhance the overall light output and improve detection sensitivity for horseradish peroxidase (HRP).

Main Methods:

• Examined four distinct treatments applied to luminol solutions to assess their impact on chemiluminescence.
• Evaluated the effects of ammonium persulphate addition, ultraviolet irradiation, and photoactive dye pretreatment.
• Assessed the influence of luminol purity, including recrystallization techniques, on detection limits.

Main Results:

• Ammonium persulphate addition resulted in over a tenfold increase in light output.
• Ultraviolet irradiation and photoactive dye pretreatment each increased light output approximately fourfold.
• Luminol purity was identified as the most critical factor for detection sensitivity, with recrystallization improving the detection limit by 13-fold.

Conclusions:

• Optimizing luminol purity and employing specific chemical treatments can effectively eliminate lag times and enhance chemiluminescence.
• These improvements lead to a significantly lower detection limit for horseradish peroxidase (HRP), advancing assay sensitivity.
• The findings suggest that contaminants interfering with enhancer radicals are responsible for lag times and reduced sensitivity.