This disclosure describes multi-fluid kits for three-dimensional printing, three-dimensional printing kits, and methods of sensing metal ions using three-dimensional printed ion sensors. In one example, a multi-fluid kit for three-dimensional printing can include a fusing agent and an ion-sensing agent. The fusing agent can include water and an electromagnetic radiation absorber. The electromagnetic radiation absorber can absorb radiation energy and convert the radiation energy to heat. The ion-sensing agent can include water and a redox-active inorganic salt.

A cost-effective and limited interaction explosive detector for dangerous, illegal, and/or illicit substances such as explosives, flammable or volatile fluids, and/or other appropriate substances is described. The explosive detector may be integrated into various containers or packages, such as cardboard boxes, paper envelopes, metal shipping containers, and/or other containers or packaging. The integrated explosive detector may provide a visual indication when a subject substance is encountered. The integrated explosive detector may include a port or vent that allows for ambient flow of fluids, such as air, between an interior of the container and the outside environment.

Provided herein are processes for preparing fluorescent 1-cyano-2-substituted isoindole compounds or N-substituted phthalazinium compounds, comprising reacting an aromatic dialdehyde or aromatic aldehyde-ketone compound with a material that contains primary amino or hydrazine groups, and assaying methods involving the processes thereof.

The disclosure directed to methods for measuring an analyte alone or in combination with total protein in biological samples. More particularly, the disclosure relates to methods for measuring an analyte and/or total protein using one or more colorimetric reagents alone or in combination with protein precipitation reagents.

The disclosure directed to methods for measuring an analyte alone or in combination with total protein in biological samples. More particularly, the disclosure relates to methods for measuring an analyte and/or total protein using one or more colorimetric reagents alone or in combination with protein precipitation reagents.

A gas detection element for detection of a measurement target gas is provided. The gas detection element includes a gas detection layer including a chemochromic pigment; and a spacer. The spacer is permeable to the measurement target gas, is disposed on a first surface of the gas detection layer, and has an area smaller than an area of the gas detection layer.

A method of sterilisation, certification and traceability of liquid nitrogen, includes the steps of preparing a container, provided with an opening, in use, at the top, and pouring into it a batch of liquid nitrogen to be sterilised; providing an identification element uniquely associable with the batch of liquid nitrogen, said identification element including an indicator of the sterilisation state of the batch contained in said container configured to modify its appearance following exposure to ultraviolet radiation; associating the identification element with the container of the batch of liquid nitrogen to be sterilised, positioning it in a portion of said container, adjacent to said opening; carry out a batch sterilisation treatment through exposure to ultraviolet radiation for a predetermined period of time, to modify at least one characteristic of the indicator to certify the sterilisation of the batch.

An embodiment provides a method for measuring arsenic in a sample, showing marked increase in sensitivity over previous methods including: preparing a compound of metal-plated zinc and zinc; introducing the compound to an acidified sample, wherein the sample contains an amount of arsenic, wherein the compound reduces the amount of arsenic to produce arsine gas; wherein sufficient hydrogen gas is produced to purge the sample solution; wherein the arsine gas is completely purged from the sample and captured on a test pad, wherein the pad comprises mercuric bromide, wherein the capturing produces a color change of the pad; and measuring the amount of arsenic in the sample by measuring the color change of the pad. Other aspects are described and claimed.

Systems, indicator wipe product, and methods thereof used to detect the presence of cationic polymer residues on a surface are described. In various embodiments, the cationic polymer to be detected comprises a quaternary silane residual antimicrobial. The indicator wipe may comprise a woven, nonwoven, or double-knit fabric, cotton, functional cellulose, or open cell foam material substrate impregnated with an aqueous dye solution comprising a sulfonephthalein dye. The indicator wipe may be configured to differentiate between traditional monomer quaternary ammonium compounds and cationic polymers such as quaternary silane compounds used in residual antimicrobial coatings by color changes on the indicator wipe and by observing if cationic-dye complexes diffuse by chromatography on the indicator wipe.

Systems, indicator wipe product, and methods thereof used to detect the presence of cationic polymer residues on a surface are described. In various embodiments, the cationic polymer to be detected comprises a quaternary silane residual antimicrobial. The indicator wipe may comprise a woven, nonwoven, or double-knit fabric, cotton, functional cellulose, or open cell foam material substrate impregnated with an aqueous dye solution comprising a sulfonephthalein dye. The indicator wipe may be configured to differentiate between traditional monomer quaternary ammonium compounds and cationic polymers such as quaternary silane compounds used in residual antimicrobial coatings by color changes on the indicator wipe and by observing if cationic-dye complexes diffuse by chromatography on the indicator wipe.