PH Indicators

Pyranine (HPTS; Solvent Green 7) is a cell-impermeant pH-sensitive fluorescent indicator. Pyranine acts as a class of fluorescent chemosensor for the Cu⁺ ion. Pyranine is used as a coloring agent, biological stain, optical detecting reagent, and pH indicator (Ex/Em = 450/510 nm).

Carboxy-SNARF 1 (5/6-mixture) (SNARF 1) is a fluorescent probe that is sensitive to pH (Ex: 488 nm). Carboxy-SNARF 1 (5/6-mixture) can be used for measurement pH. Carboxy-SNARF 1 (5/6-mixture) exhibits a significant emission shift from yellow-orange (Em: 580 nm) to deep red fluorescence (Em: 640 nm) under acidic and basic conditions (pH=7-8), respectively.

Phenol red (Phenolsulfonephthalein) is a pH indicator dye, relying on a distinct color change from pink to yellow in case of a positive reaction .

BCECF is a cell-impermeant pH-sensitive fluorescent dye. BCECF allows measurements in the physiological pH range 6.0-8.0. Excitation ratio: 490/440 nm; Emission intensity: 535 nm.

BCECF Acetoxymethyl ester is a cell membrane permeable compound widely-used as a fluorescent indicator for intracellular pH. BCECF Acetoxymethyl ester could diffuse through the cell membrane and intracellular esterase cleave the ester bond releasing BCECF (HY-101882). BCECF allows measurements in the physiological pH range 6.0-8.0. Excitation ratio: 490/440 nm; Emission intensity: 535 nm.

pH630 Deep Red TFP Ester, Amine reactive is a fluorescent labeling reagent combining pH responsiveness and amine-targeting capabilities. It combines pH sensitivity and amine-specific labeling, primarily used for highly specific, low-background fluorescent labeling and imaging of primary amine-containing biomolecules in acidic environments (Ex/Em = 630/650 nm).

pH630 Deep Red maleimide, Thiol Reactive is a fluorescent labeling reagent combining pH responsiveness and thiol targeting capabilities. It combines pH sensitivity and thiol-specific labeling, primarily used for highly specific, low-background fluorescent labeling and imaging of thiol-containing biomolecules in acidic environments (Ex/Em = 630/650 nm).

9-Amino-6-chloro-2-methoxyacridine is a pH sensitive fluorescent probe. 9-Amino-6-chloro-2-methoxyacridine has been frequently used to measure changes in vacuolar pH when a specific substrate crosses the tonoplast through a putative H⁺/solute antiport system.

9-Aminoacridine, a fluorescent probe, acts as an indicator of pH for quantitative determination of transmembrane pH gradients (inside acidic). 9-Aminoacridine is an antimicrobial. 9-Aminoacridine exerts its antimicrobial activity by interacting with specific bacterial DNA and disrupting the proton motive force in K. pneumoniae. 9-Aminoacridine is a HIV-1 inhibitor and inhibits HIV LTR transcription highly dependent on the presence and location of the amino moiety. 9-Aminoacridine inhibits virus replication in HIV-1 infected cell lines. 9-Aminoacridine is used as a Rifampin (RIF; HY-B0272) adjuvant for the multidrug-resistant K. pneumoniae infections.

DHPDS disodium salt is a pH-sensitive fluorescent dye. DHPDS disodium salt is used to measure intracellular pH (pHi) from the surface fluorescence of the isolated perfused rat liver.

DND-189, a low-pH fluorescent probe, is sensitive to neutral and low pH range. DND-189 can be used to measure the pH of acidic organelles.

Methyl Orange is a soluble azo dye commonly used as an acid-base indicator and for staining cells and tissue sections, as well as for dyeing textiles. Methyl Orange appears red at a pH of 3.1 and changes to bright yellow as the pH increases to 4.4. Methyl Orange (500 mg/L) exhibits cytotoxicity and can cause DNA damage.

Indigo carmine is an efficient reagent for the determination of ozone by chemlluminescence (CL).

5(6)-Carboxynaphthofluorescein is a pH-dependent fluorophore. 5(6)-Carboxynaphthofluorescein shows good sensitivity in an alkaline pH range and it can be exploited in the construction of fiber-optic pH sensors. 5(6)-Carboxynaphthofluorescein can be used as a fluorescent pH indicator (Ex/Em=593/668 nm).

OG 488, acid, a fluorescent pH indicator, has many applications in biochemistry and neurosciences.

Thymol blue is a reversible pH indicator that responds to the pH of the solution through structural changes of protonation and deprotonation. Thymol blue is red (HI^- form) under acidic conditions and blue (I^2- form) under alkaline conditions. Quantitative detection is achieved through the absorption peak shift (435 nm/596 nm) of the UV-visible spectrum. Thymol blue selectively responds to pH changes, changing from red to yellow at pH 1.2-2.8 and from yellow to blue at pH 8.0-9.6. Thymol blue can be fixed in a silica gel matrix through sol-gel technology to form a solid-state sensor for in-situ pH measurement in the marine environment and acid-base monitoring in the biomedical field[1][2].

Thymol Blue sodium is an acid-base indicator used to indicate changes in pH. Thymol Blue sodium fades from red to yellow at pH 1.2 to 2.8 and from yellow to blue at pH 8.0 to 9.6. Quantitative detection is achieved through the absorption peak shift (435 nm/596 nm) of the UV-visible spectrum. Thymol blue sodium can be fixed in a silica gel matrix through sol-gel technology to form a solid-state sensor for in-situ pH measurement in the marine environment and acid-base monitoring in the biomedical field.

Thymolphthalein is an electrochemically active dye due to the presence of thymol fragments. Thymolphthalein is a Phthalein dye used as an acid-base indicator. It is colourless in acid pH and is blue in basic pH.

Bromophenol blue sodium is a pH indicator. It changes from yellow at pH 3.0 to blue at pH 4.6. Bromophenol blue sodium is also used as a tracking dye to monitor the process of agarose gel electrophoresis and polyacrylamide gel electrophoresis.