Innovated single flush on-line solid-phase extraction in bead injection format for flow programming-based...

Area of Science:

• Analytical Chemistry
• Clinical Chemistry
• Biomedical Engineering

Background:

• Automated flow analysis is crucial for reaction-based assays but limited by aggressive reagents damaging manifolds.
• On-line solid-phase extraction (SPE) offers a solution to enhance durability, reproducibility, and automation in flow analysis systems.

Purpose of the Study:

• To develop and validate an automated on-line SPE method for sensitive and selective creatinine determination in human urine using sequential injection analysis.
• To improve the robustness and efficiency of flow analysis for clinical bioanalysis by addressing reagent-induced manifold degradation.

Main Methods:

• Sequential injection analysis coupled with bead injection on-line SPE utilizing a strong cation exchanger.
• UV spectrophotometric detection at 235 nm (with subtraction at 270 nm) for creatinine quantification.
• Automated column packing/disposal, calibration, and a novel zone sequencing technique for accelerated SPE.

Main Results:

• The method achieved high sensitivity and selectivity for creatinine in diluted human urine samples.
• A single run duration was under 3.5 minutes with a relative standard deviation <5.0%.
• Linear calibration range was 1.0-15.0 mmol/L creatinine in urine (R>0.999), with accuracy comparable to routine enzymatic assays.

Conclusions:

• The developed automated on-line SPE method significantly improves flow analysis for creatinine determination, offering enhanced durability and automation.
• The bead injection and zone sequencing techniques accelerate the process and broaden the calibration range while minimizing matrix effects.
• This approach provides a robust, accurate, and efficient alternative for clinical bioanalysis of creatinine in human urine.