Accelerated micro-sequential injection in lab-on-valve format, applied to enzymatic assays

Area of Science:

• Analytical Chemistry
• Biotechnology

Background:

• Sequential Injection (SI) analysis offers advantages in reagent consumption and automation.
• Traditional SI assay cycles can be time-consuming, limiting throughput.
• Micro-flow systems and optimized protocols are key to enhancing analytical methods.

Purpose of the Study:

• To accelerate the assay cycle of sequential injection (SI) analysis.
• To achieve high sampling frequencies comparable to flow injection (FI) using SI.
• To demonstrate the applicability of a micro-miniaturized SI system for rapid enzymatic assays.

Main Methods:

• Micro-miniaturization of the SI system using the lab-on-valve (LOV) format.
• Optimization of the assay protocol for stopped-flow reaction rate measurements.
• Simultaneous processing of two sample injections within the same manifold.

Main Results:

• Average assay time reduced from 200s to approximately 30s.
• Achieved high linearity (r(2) > 0.999) for glucose and ethanol assays across tested concentration ranges.
• Demonstrated relative standard deviations below 3% for both glucose and ethanol assays.
• Attained sampling frequencies comparable to flow injection (FI).

Conclusions:

• The micro-miniaturized LOV-SI system significantly accelerates assay cycles.
• This approach retains the benefits of SI, including low reagent consumption and waste generation.
• The method is versatile and applicable to various SI reagent-based assays, including enzymatic analyses of glucose and ethanol.