UV SPECTROPHOTOMETRIC FLOW-THROUGH MULTIPARAMETER SENSOR FOR THE SIMULTANEOUS DETERMINATION OF ACETAMINOPHEN, ACETYLSALICYLIC ACID, AND CAFFEINE

ABSTRACT

A single triparameter flow-through sensor with U.V. detection is described in this study for the simultaneous determination of acetaminophen, acetylsalicylic acid and caffeine. The use of an solid phase (C₁₈ silica gel) placed in an on-line microcolumn provides the sequential arrival of the analytes to the detection solid zone (also C₁₈ silica gel beads placed in a flow cell), making possible the determination with only one injection. A flow rate of 1.42 mL min⁻¹ was pumped and detection wavelength was 272 nm. The linear dynamic ranges were 10–100, 40–500 and 4–50 µg mL⁻¹, for acetaminophen, acetylsalicylic acid and caffeine, respectively. Limit of detection were from 0.3 to 0.8 µg mL⁻¹ and limit of quantitation were from 1.0 and 2.7 µg mL⁻¹ with RSDs from 1.2 to 3.4 (n = 10), respectively. The proposed method was applied to the determination of acetaminophen, acetylsalicylic acid and caffeine in pharmaceutical preparations. The results were compared with those obtained from an HPLC method and they showed a good agreement.

Keywords:

• Acetaminophen
• Acetylsalicylic acid
• Caffeine
• Sensor
• Determination

ACKNOWLEDGMENTS

The authors acknowledge the financial support from the Dirección General de Enseñanza Superior (DGES) of the Ministerio de Educación, Cultura y Deporte (project No. PB98-0301). A. Domínguez Vidal is grateful to the same Ministerio for a doctoral fellowship.