A water quality analysis system is calibrated without using any organic fluorescence material such as phenanthrene. The water quality analysis system analyzes a component to be measured contained in a liquid sample by a fluorescence spectroscopy, and that comprises a light irradiation section that irradiates the liquid sample with a light having an excitation wavelength of the component to be measured, a light detection section that detects a fluorescence of the component to be measured emitted from the liquid sample, a calculation unit that calculates a concentration of the component to be measured by using a fluorescence intensity obtained by the light detection section, and a solid fluorescence reference member that is arranged on an optical path between the light irradiation section and the light detection section and that emits the fluorescence by the light from the light irradiation section at a time of calibration.

A measuring device for measuring a measurand of a medium includes a measuring cell, a measuring cell receptacle for holding the measuring cell, and a measuring apparatus for measuring the measurand, wherein the measuring cell includes a measurement chamber containing the medium and a reference chamber separate from the measurement chamber and containing a reference medium. The measurement chamber and the reference chamber are arranged relative to one another such that the measuring cell can be inserted into the measuring cell receptacle in a measuring position, in which measurements of the measurand of the medium can be performed by means of the measuring apparatus, and can be inserted into the measuring cell receptacle in a reference position, in which reference measurements of a reference variable of the reference medium in the reference chamber can be performed by means of the measuring apparatus.

A water quality detection system includes a water detection device, a water-leaving airbag and a gas filling module. The water detection device includes a body, a sensing light source, a fluorescent sensing film, an optical detector and a processor. The sensing light source is disposed in the body and emits sensing light. The fluorescent sensing film is disposed on the surface of the body and generates feedback light in response to the sensing light. The optical detector is disposed in the body and generates a concentration signal in response to the feedback light. The processor determines a concentration of a component to be measured in an aqueous solution according to the concentration signal. The gas filling module is configured to inflate or deflate the water-leaving airbag. The water-leaving airbag is disposed at the body and configured to float the fluorescent sensing film above the liquid surface.

Provided is a method for sensing methyl salicylate, which is a plant hormone released when a plant is infected with a disease. One aspect of the present embodiment relates to a method for sensing methyl salicylate, including detecting a reaction product of a terbium-sulfoxide complex represented by the predetermined formula and methyl salicylate.

A composition includes a functionalized fluorescent dye. The functionalized fluorescent dye includes an isothiocyanate-containing dye functionalized with a functional group. The functional group includes an aromatic compound with a primary amine. The functionalized fluorescent dye can be mixed with a fluid to form a tracer fluid for tracing fluid flow in a subterranean formation.