A method and a device allow measurement of the pH value of a solution. The method includes illuminating a solution containing a pH indicator and a pH changer with light emitted from a light emitting element, receiving light transmitted through the solution with a light receiving element, measuring absorbance with monochromatic light selectively from the received transmitted light, and calculating a pH value corresponding to the measured absorbance based on a predefined absorbance table. The device includes an illuminator that illuminates a solution containing a pH indicator and a pH changer with light emitted from a light emitting element, a light receiver that receives light transmitted through the solution, a measurer that measures absorbance with light with a wavelength of monochromatic light selectively from the received transmitted light, and a calculator that calculates a pH value corresponding to the absorbance measured by the measurer based on a predefined absorbance table.

The present disclosure provides a genetically encoded calcium indicator (GECI), nucleic acids encoding the GECI, and host cells comprising the GECI. The present disclosure also provides methods of detecting a change in the intracellular concentration of a cell expressing a GECI of the present disclosure.

The present disclosure provides a genetically encoded calcium indicator (GECI), nucleic acids encoding the GECI, and host cells comprising the GECI. The present disclosure also provides methods of detecting a change in the intracellular concentration of a cell expressing a GECI of the present disclosure.

A strip structure for measuring potassium ions includes: a strip having an inner space for receiving a solution therein and being formed in a plate shape; an inlet formed in the strip and capable of injecting a solution into the inner space of the strip; a potassium ion selective membrane arranged in the inner space and capable of permeating potassium ions of the solution; and a first working electrode extending in a strip shape, wherein one side of the first working electrode is arranged inside the potassium ion selective membrane and the other side of the first working electrode is on a surface of the strip.

A strip structure for measuring potassium ions includes: a strip having an inner space for receiving a solution therein and being formed in a plate shape; an inlet formed in the strip and capable of injecting a solution into the inner space of the strip; a potassium ion selective membrane arranged in the inner space and capable of permeating potassium ions of the solution; and a first working electrode extending in a strip shape, wherein one side of the first working electrode is arranged inside the potassium ion selective membrane and the other side of the first working electrode is on a surface of the strip.

Provided herein are compositions and methods for quantifying polyphosphates. In particular, provided herein are solution and substrate based assays for quantifying polyphosphates in complex samples.

Provided is a diagnostic kit for determining infection with Methicillin-Resistant Staphylococcus aureus (MRSA) in a specimen, and a method for determining the infection with MRSA using the diagnostic kit is performed by visually observing a color change after LAMP reaction, and the color change is caused by a change in a magnesium concentration and confirmed using a specific dye compound which sensitively reacts with magnesium ions. The amplification of the MRSA DNA is performed using the loop-mediated isothermal amplification (LAMP), so that the diagnostic kit has advantages of being conveniently used anytime and anywhere and quickly diagnosing.

Provided is a diagnostic kit for determining infection with Methicillin-Resistant Staphylococcus aureus (MRSA) in a specimen, and a method for determining the infection with MRSA using the diagnostic kit is performed by visually observing a color change after LAMP reaction, and the color change is caused by a change in a magnesium concentration and confirmed using a specific dye compound which sensitively reacts with magnesium ions. The amplification of the MRSA DNA is performed using the loop-mediated isothermal amplification (LAMP), so that the diagnostic kit has advantages of being conveniently used anytime and anywhere and quickly diagnosing.

Provided are novel rhodol-based compounds, the preparation method thereof, and use thereof in Tl.sup.+ flux assays. The fluorescent thallium ion sensor compounds have a rhodol fluorophore attached to an amino dicarboxylic acid metal binding moiety. The compounds are prepared in the “pro-dye” form, with the rhodol oxygen and the carboxylic acids of the metal binding unit masked by protecting groups. The disclosed compounds may be used as more red-shifted and less pH-sensitive variants of Thallos.

Provided are novel rhodol-based compounds, the preparation method thereof, and use thereof in Tl.sup.+ flux assays. The fluorescent thallium ion sensor compounds have a rhodol fluorophore attached to an amino dicarboxylic acid metal binding moiety. The compounds are prepared in the “pro-dye” form, with the rhodol oxygen and the carboxylic acids of the metal binding unit masked by protecting groups. The disclosed compounds may be used as more red-shifted and less pH-sensitive variants of Thallos.