Disclosed is a method for detecting toxic metal ions in a sample. The method includes: a) preparing a solution of organic acid-bound gold nanoparticles; b) adding a sample containing toxic metal ions to the solution prepared in a) to allow the gold nanoparticles to aggregate; c) dropping the reaction solution obtained in b) onto a silicon substrate and drying the reaction solution such that the gold nanoparticle aggregates are immobilized on the silicon substrate; and d) analyzing the characteristics of the gold nanoparticles immobilized on the silicon substrate. The method enables the detection of even a trace amount of toxic metal ions in a sample with high sensitivity. Therefore, the method can be applied to the management of water quality in food service providers and hospitals, the measurement of contaminants in water supply and drainage systems, and the management of industrial wastewater. Furthermore, the method is expected to be widely applicable to water purifiers and the food and beverage industry in the future.

A microwave impedance microscope including a tuning fork having a high-aspect ratio etched metal tip electrode extending transversely to one tine of the fork and having a high aspect ratio to thereby reduce parasitic capacitance. The metal tip may be electrochemically etched from a wire, then bonded to the tine. The fork is slightly inclined from the surface of the sample and the tip electrode projects transversely to the fork. A microwave signal is impressed on the tip. Microwave circuitry receives microwave signals reflected from the sample back into the tip and demodulates the reflected signal according to the impressed signal. Further circuitry further demodulates the reflected signal according to the lower-frequency signal causing the fork to oscillate at its mechanically resonant frequency. A multi-wavelength matching circuit interposed between the microwave circuitry and the probe includes a coaxial cable of length half a fundamental microwave wavelength.

An apparatus and method of operating an atomic force profiler (AFP), such as an AFM, using a feedforward control signal in subsequent scan lines of a large area sample to achieve large throughput advantages in, for example, automated applications.

An apparatus and method of operating an atomic force profiler (AFP), such as an AFM, using a feedforward control signal in subsequent scan lines of a large area sample to achieve large throughput advantages in, for example, automated applications.

The present invention is related to a membrane electrochemical signal detection system, which comprises a detection platform and a probe, wherein the detection platform comprises a substrate having a cavity; a hydrogel layer disposed in the cavity of the substrate; and a carrier film disposed above the substrate and the hydrogel layer with at least one through hole corresponding to the cavity of the substrate as a sample slot. The surface of the probe is covered by an insulating layer and a metal for detection is exposed at a tip portion of the probe.

The present invention is related to a membrane electrochemical signal detection system, which comprises a detection platform and a probe, wherein the detection platform comprises a substrate having a cavity; a hydrogel layer disposed in the cavity of the substrate; and a carrier film disposed above the substrate and the hydrogel layer with at least one through hole corresponding to the cavity of the substrate as a sample slot. The surface of the probe is covered by an insulating layer and a metal for detection is exposed at a tip portion of the probe.

A method includes: removing at least a part of an oxide formed on a surface of the sample by relatively scanning the surface of the sample in X and Y directions parallel to the surface while bringing a probe into contact with the surface of the sample; detecting a signal by bringing the probe into contact with the surface of the sample from which at least a part of the oxide is removed at a predetermined detection position in the X direction or the Y direction while a bias voltage is applied to the sample; calculating a spreading resistance value based on the signal; and retracting the probe to keep the probe relatively away from the surface in a Z direction perpendicular to the surface while relatively moving the probe to a next detection position to start scanning the sample from the next detection position.

A method includes: removing at least a part of an oxide formed on a surface of the sample by relatively scanning the surface of the sample in X and Y directions parallel to the surface while bringing a probe into contact with the surface of the sample; detecting a signal by bringing the probe into contact with the surface of the sample from which at least a part of the oxide is removed at a predetermined detection position in the X direction or the Y direction while a bias voltage is applied to the sample; calculating a spreading resistance value based on the signal; and retracting the probe to keep the probe relatively away from the surface in a Z direction perpendicular to the surface while relatively moving the probe to a next detection position to start scanning the sample from the next detection position.

A method for determining a value of a local contact potential difference by noncontact atomic force microscopy. For one or more cantilever positions above a surface of a sample: i) determining two distinct voltage values of DC voltage applied between an oscillating cantilever and the sample, and ii) determining, by one or more processors, a value of a local contact potential difference based, at least in part, on the two distinct voltage values that were determined.

A method for determining a value of a local contact potential difference by noncontact atomic force microscopy. For one or more cantilever positions above a surface of a sample: i) determining two distinct voltage values of DC voltage applied between an oscillating cantilever and the sample, and ii) determining, by one or more processors, a value of a local contact potential difference based, at least in part, on the two distinct voltage values that were determined.