A sensitive and specific method for isoniazid determination based on selective adsorption using an isoniazid...

Area of Science:

• Analytical Chemistry
• Sensor Technology
• Biomedical Sensing

Background:

• Direct determination of isoniazid (INH) in biological samples is crucial for therapeutic drug monitoring.
• Existing methods may lack sensitivity, selectivity, or simplicity for rapid analysis.
• Piezoelectric sensors offer a sensitive platform for mass-based detection.

Purpose of the Study:

• To develop and characterize a novel ion-selective piezoelectric (ISP) sensor for the direct determination of isoniazid.
• To evaluate the sensor's performance using different synthesized activants.
• To assess the sensor's applicability for analyzing isoniazid in real biological fluid samples.

Main Methods:

• Fabrication of an ISP sensor by coating a PVC film with synthesized activants (INH-phosphotungstate, INH-silicotungstate, INH-[BiI(4)](-)) onto a piezoelectric quartz crystal.
• Investigated the frequency response of the sensor in relation to varying isoniazid concentrations.
• Determined calibration linearity, detection limits, and recovery rates under physiological conditions (pH 7.0, 37°C).

Main Results:

• The ISP sensor demonstrated a selective mass response to isoniazid, with observed frequencies decreasing as INH concentration increased.
• Linear calibration ranges were established from 6x10⁻⁸ M to 2x10⁻³ M for INH-phosphotungstate and 2x10⁻⁷ M to 2x10⁻³ M for the other two activants.
• Achieved low detection limits (down to 6x10⁻⁸ M) and high recovery rates (98-102%) with good precision (R.S.D. ≤ 2%).

Conclusions:

• The developed ISP sensor is a selective, sensitive, and simple tool for the direct determination of isoniazid in body fluids.
• The sensor exhibits performance comparable to conventional pharmacopeia methods, suggesting its potential for clinical applications.
• The use of synthesized activants in the PVC film enhances the sensor's specificity and sensitivity for isoniazid detection.