An enzymatic reactor based on silver solid amalgam powder was suggested as the main part of biosensors in flow systems for the first time. Biosensors were tested with following enzymes: ascorbate oxidase, glucose oxidase, catalase, tyrosinase and laccase. The current response of each biosensor was optimized with respect to the detection potential, flow rate, the injection and reactor volume. Relative standard deviation for detection with the studied enzymes was found to be in the range of 0.81–2.1 %. The biosensor with the ascorbate oxidase reactor was used for determination of ascorbic acid in the vitamin tablets Celaskon.

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Two enzymatic biosensors with amalgam powder reactors and twelve enzymatic biosensors with various silica powder reactors were fabricated and tested in this work. The enzymatic reactors based on silver amalgam powder provide high sensitivity and they are convenient for faster flow rates. Experiments with six silica materials showed that mesoporous silica SBA‐15 was the best one in terms of covering by enzymes, sensitivity and lifetime of biosensors. The current response of the SBA15‐glucose oxidase (GOx) sensor started to decrease only after 200 day testing and after 406 days the peak current was still 35.9 % of the initial value. The used amalgam tubular detector in a flow system allowed working at highly negative potentials, which significantly increased the sensitivity of determinations. Statistical results of parallel measurement of model solutions with the fabricated biosensors show their high accuracy (RSD=0.28–1.81 %) and sensitivity (6.2–14.3 µmol L−1). The proposed SBA15‐GOx biosensor was successfully used for determination of glucose in commercial honey.

An application of the flow differential pulse voltammetry with tubular detector based on silver solid amalgam for determination of antineoplastic drug lomustine in pharmaceutical preparations is presented. The highest sensitivity was obtained in [0.10 mol dm−3 MES; 2.00 mol dm−3 NaCl; pH 6.0]:EtOH (9 : 1) with flow rate 0.50 mL min−1, and the magnitude of the modulation amplitude −0.070 V. The calibration dependence was linear in the range 1×10−6–1 × 10−4 mol dm−3 (R2=0.999). The limit of detection was 1.5×10−7 mol dm−3. This method was successfully used for determination of lomustine in real samples of chemotherapy drug CeeNU Lomustine 40 mg.