Gated voltammetry methods

A handheld measuring device for signaling a user to add additional sample to a sensor strip received by the handheld measuring device, the sensor strip including at least two electrodes, the handheld measuring device comprising:

• at least two contacts each electrically coupled to respective ones of the at least two electrodes responsive to the sensor strip being received by the handheld measuring device;
• and
• electrical circuitry including a processor in electrical communication with an electric charger and the at least two contacts, where the processor is operable to:
• apply a gated voltammetric pulse sequence from the electric charger to the sample through the at least two electrodes of the sensor strip, the pulse sequence having at least two duty cycles,
• wherein each of the at least two duty cycles includes an excitation and a relaxation, and
• wherein the excitations of the at least two duty cycles include a potential varied with time and the relaxations of the at least two duty cycles include a current reduction to at least one-half the current flow at the excitation maxima;
• determine if the sensor strip is under-filled by comparing at least one current value recorded from the gated voltammetric pulse sequence including the at least two duty cycles to a pre-selected value;
• and
• signal the user to add additional sample to the sensor strip if the sensor strip is under-filled.

A handheld measuring device for determining a concentration of an analyte in a sample, the handheld measuring device comprising:

• at least two contacts;
• and
• electrical circuitry including a processor in electrical communication with an electric charger and the at least two contacts, where the processor is operable to carry out a voltammetric method comprising:
• applying a pulse sequence from the electric charger to the sample via the at least two contacts, the pulse sequence comprising at least two duty cycles having excitation/relaxation time ratios from 0.3 to 0.2, wherein each of the at least two duty cycles includes a relaxation, and the relaxations of the at least two duty cycles include a current reduction to at least one-half the current flow at the excitation maxima;
• measuring resulting currents from the at least two duty cycles;
• and
• determining the concentration of the analyte in the sample from the resulting currents.

A handheld measuring device for determining a hematocrit concentration of a blood sample, the handheld measuring device comprising:

• at least two contacts;
• and
• electrical circuitry including a processor in electrical communication with an electric charger and the at least two contacts, where the processor is operable to carry out a voltammetric method comprising:
• applying a gated voltammetric pulse sequence from the electric charger to the blood sample via the at least two contacts, the pulse sequence having at least two duty cycles,
• wherein each of the at least two duty cycles includes an excitation and a relaxation, and
• wherein the excitations of the at least two duty cycles include a potential varied with time and the relaxations of the at least two duty cycles include a current reduction to at least one-half the current flow at the excitation maxima;
• measuring resulting currents from at least one of the excitations;
• applying a semi-integral data treatment to the resulting currents, the semi-integral data treatment providing a peak portion;
• and
• quantitatively relating the peak portion to the hematocrit concentration of the blood sample.

A handheld measuring device for determining a percent hematocrit of a blood sample, the handheld measuring device comprising:

• at least two contacts;
• and
• electrical circuitry including a processor in electrical communication with an electric charger and the at least two contacts, where the processor is operable to carry out a voltammetric method comprising:
• applying a gated voltammetric pulse sequence form the electric charger to the blood sample via the at least two contacts, the pulse sequence having at least two duty cycles,
• wherein each of the at least two duty cycles includes an excitation and a relaxation, and
• wherein the excitations of the at least two duty cycles include a potential varied with time and the relaxations of the at least two duty cycles include a current reduction to at least one-half the current flow at the excitation maxima;
• measuring resulting currents from at least one of the excitations;
• applying a derivative data treatment to the resulting currents, the derivative data treatment providing a negative derivative peak and a positive derivative peak;
• determining a ratio of the negative derivative peak to the positive derivative peak;
• and
• quantitatively relating the ratio to the percent hematocrit in the blood sample.

A handheld measuring device for determining an amount of active ionizing agent available to react with an analyte, the handheld measuring device comprising:

• at least two contacts;
• and
• electrical circuitry including a processor in electrical communication with an electric charger and the at least two contacts, where the processor is operable to:
• apply a gated voltammetric pulse sequence from the electric charger to a sample in a sensor strip through the at least two contacts, the pulse sequence having at least two duty cycles, the sample including an analyte and active ionizing agent,
• wherein each of the at least two duty cycles includes an excitation and a relaxation,
• wherein the excitations of the at least two duty cycles include a potential varied with time and the excitations include forward and reverse scans, and
• wherein the relaxations of the at least two duty cycles include a current reduction to at least one-half the current flow at the excitation maxima;
• measure resulting currents from the forward and the reverse scans of at least one of the excitations;
• determine a ratio of the resulting currents from the forward and the reverse scans;
• compare the determined ratio to a previously determined correlation ratio and a percent active ionizing agent;
• and
• determine the amount of the active ionizing agent available to react with the analyte.

A handheld measuring device for determining a concentration of an analyte in a sample, the handheld measuring device comprising:

• at least two contacts;
• and
• electrical circuitry including a processor in electrical communication with an electric charger and the at least two contacts, where the processor is operable to carry out a voltammetric method comprising:
• applying a pulse sequence from the electric charger to the sample via the at least two contacts, the pulse sequence comprising at least two duty cycles having excitation/relaxation time ratios from 0.3 to 0.2, wherein each of the at least two duty cycles includes an excitation, and wherein the excitations comprise a potential varied linearly at a rate of at least 2 mV/sec;
• measuring resulting currents from the at least two duty cycles;
• and
• determining the concentration of the analyte in the sample from the resulting currents.

A handheld measuring device for determining a concentration of an analyte in a sample, the handheld measuring device comprising:

• at least two contacts;
• and
• electrical circuitry including a processor in electrical communication with an electric charger and the at least two contacts, where the processor is operable to carry out a voltammetric method comprising:
• applying a pulse sequence from the electric charger to the sample via the at least two contacts, the pulse sequence comprising at least two duty cycles having excitation/relaxation time ratios from 0.3 to 0.2, wherein each of the at least two duty cycles includes an excitation, and wherein the excitations are acyclic and substantially exclude a reverse oxidation peak or a reverse reduction peak of a measurable species responsive to the concentration of the analyte in the sample;
• measuring resulting currents from the at least two duty cycles;
• and
• determining the concentration of the analyte in the sample from the resulting currents.

A handheld measuring device for determining a concentration of an analyte in a sample, the handheld measuring device comprising:

• at least two contacts;
• and
• electrical circuitry including a processor in electrical communication with an electric charger and the at least two contacts, where the processor is operable to carry out a voltammetric method comprising:
• applying a pulse sequence from the electric charger to the sample via the at least two contacts, the pulse sequence comprising at least two duty cycles having excitation/relaxation time ratios from 0.3 to 0.2, wherein each of the at least two duty cycles includes an excitation;
• measuring resulting currents from the at least two duty cycles;
• and
• determining the concentration of the analyte in the sample from the resulting currents, wherein
• the excitations are acyclic and terminate before initiation of a reverse current peak,
• the excitations are acyclic and substantially exclude forward and reverse oxidation and reduction peaks of a measurable species responsive to the concentration of the analyte in the sample, or
• the excitations are acyclic and are substantially within a diffusion limited current region of a redox pair.