An embodiment provides a method for measuring total chlorine in a seawater sample, including: preparing a thiocarbamate-based indicator; introducing the thiocarbamate-based indicator to a seawater sample, wherein the seawater sample contains an amount of total chlorine; adding an additive to the seawater sample, wherein the additive accelerates the reaction rate between the thiocarbamate-based indicator and total chlorine and causes a change in fluorescence of the seawater sample; and measuring the amount of total chlorine in the seawater sample by measuring an intensity of the fluorescence. Other aspects are described and claimed.

An embodiment provides a method for measuring total chlorine in a seawater sample, including: preparing a thiocarbamate-based indicator; introducing the thiocarbamate-based indicator to a seawater sample, wherein the seawater sample contains an amount of total chlorine; adding an additive to the seawater sample, wherein the additive accelerates the reaction rate between the thiocarbamate-based indicator and total chlorine and causes a change in fluorescence of the seawater sample; and measuring the amount of total chlorine in the seawater sample by measuring an intensity of the fluorescence. Other aspects are described and claimed.

A method for determining whether a syrup contains a preservative at a needed level is provided. The method includes measuring a conductivity of the syrup, determining whether the measured conductivity is below a predetermined conductivity value determined based on a target syrup according to a syrup recipe, and determining whether the preservative is below the needed level in response to the measured conductivity being below the predetermined conductivity value.

A method for determining whether a syrup contains a preservative at a needed level is provided. The method includes measuring a conductivity of the syrup, determining whether the measured conductivity is below a predetermined conductivity value determined based on a target syrup according to a syrup recipe, and determining whether the preservative is below the needed level in response to the measured conductivity being below the predetermined conductivity value.

Embodiments of the present invention relate to freshness indication. In some embodiments, a freshness indicating device is provided. The freshness indicating device comprises a collector and an indicator. The collector is adapted to collect water from an object. The object includes at least one of fruits and vegetables. The indicator is adapted to indicate the freshness of the object based on the amount of the collected water. A corresponding method and a container comprising the freshness indicating device are disclosed as well.

An embodiment provides an apparatus, including: a cartridge including a base and a lid; at least one fluid line located between the base and the lid of the cartridge; at least one heating element located either on the base or the lid and aligned in intimate contact with the at least one fluid line; at least one heat sensing element in intimate contact with the at least one fluid line, where the at least one heat sensing element is spaced downstream from the at least one heating element; a supply of power to the cartridge; and a processor in electrical communication with the cartridge that executes a program of instructions to: operate the at least one heating element to produce heating of the at least one fluid line at a first position; and operate the at least one heat sensing element to detect the heat of a fluid within the at least one fluid line at a position downstream of the first position. Other embodiments are described and claimed.

An embodiment provides an apparatus, including: a cartridge including a base and a lid; at least one fluid line located between the base and the lid of the cartridge; at least one heating element located either on the base or the lid and aligned in intimate contact with the at least one fluid line; at least one heat sensing element in intimate contact with the at least one fluid line, where the at least one heat sensing element is spaced downstream from the at least one heating element; a supply of power to the cartridge; and a processor in electrical communication with the cartridge that executes a program of instructions to: operate the at least one heating element to produce heating of the at least one fluid line at a first position; and operate the at least one heat sensing element to detect the heat of a fluid within the at least one fluid line at a position downstream of the first position. Other embodiments are described and claimed.

A colorimetric sensor for detecting an analyte of interest in a fluid sample includes a lamellar photonic material having alternating layers of a first polymer layer and a second polymer layer. Each first polymer layer can be a molecularly imprinted polymer defining a cavity shaped to receive an analyte of interest. The photonic material is configured such that, when an analyte contacts the photonic material and becomes disposed within a cavity of the molecularly imprinted polymer, a refractive property of the photonic material changes, causing a detectable color change in the sensor.

A colorimetric sensor for detecting an analyte of interest in a fluid sample includes a lamellar photonic material having alternating layers of a first polymer layer and a second polymer layer. Each first polymer layer can be a molecularly imprinted polymer defining a cavity shaped to receive an analyte of interest. The photonic material is configured such that, when an analyte contacts the photonic material and becomes disposed within a cavity of the molecularly imprinted polymer, a refractive property of the photonic material changes, causing a detectable color change in the sensor.

The present disclosure provides a color chart and a test kit for estimating chemical oxygen demand of water. The color chart includes a blue component, an indigo component, an umber component, and an orange component. The test kit includes an oxidant, a reductant, an indicator, and the color chart. The present disclosure also provides a method for estimating chemical oxygen demand of water. The method includes providing a water sample; adding an oxidant to the water sample; heating the water sample; adding a reductant to the water sample; adding an indicator to the water sample, such that the water sample develops a color; and matching the color of the water sample with the color components of the color chart to estimate the chemical oxygen demand of the water sample.