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Pyranine

Pyranine is a fluorescent dye commonly used in biological research.
It is a water-soluble, pH-sensitive compound that emits bright green fluorescence when excited by ultraviolet light.
Pyranine has been utilized in a variety of applications, including as a tracer in hydrological studies, a pH indicator in cell and tissue imaging, and a probe for monitoring intracellular pH changes.
Researchers can optimize their Pyranine protocols using PubCompare.ai's AI-driven platform, which helps locate the best procedures from literature, preprints, and patents through intelligent comparisons.
This streamlines the research process and allows scientists to find the most effective Pyranine protocolls with cutting-edge technology.

Most cited protocols related to «Pyranine»

Cucumber Root Plasma Membrane Characterization

Cited 4 times

Cucumber seeds (Cucumis sativus L. var. Krak), germinated in darkness at 25 °C for 48 h, were transferred to a nutrient medium containing 10 μM Cd or Cu for 6 d. After 3 d, some of the plants exposure to heavy metals were transferred to control conditions (nutrient solution without 10 μM Cd or Cu) for another 3 d (3/3 plants). The nutrient solution (pH 5,5) contained: 1.7 mM KNO₃, 1.7 mM Ca(NO₃)₂, 0.33 mM KH₂PO₄, 0.33 mM MgSO₄, and the microelements 75 μM ferric citrate, 10 μM MnSO₄, 5 μM H₃BO₄, 1 μM CuSO₄, 0.01 μM ZnSO₄, and 0.05 μM Na₂MoO₄. The plants were grown hydroponically with a 16 h photoperiod (180 μmol m⁻² s⁻¹) at 25 °C during the day and 22 °C at night. The relative humidity in the light and dark was 70%.
PM vesicles were isolated from cucumber root microsomes by phase partitioning according to the procedure of Larsson (1985) , as modified by Kłobus (1995) . An 8 g phase system containing 6.2% (w/w) Dextran T500, 6.2% (w/w) polyethylene glycol 3350, 330 mM sorbitol, 5 mM KCl, and 5 mM Bis-Tris propane (BTP)/MES (pH 7.5) was used. The PMs obtained by this procedure were composed mainly of right-side-out vesicles and were used to determine the hydrolytic ATPase activity. Some of the vesicles were turned to the inside-out-oriented form by the method of Johansson et al. (1995) (link) and used for measurements of ATP-dependent H⁺ transport in the PM.
The hydrolytic activity of the vanadate-sensitive ATPase (PM H⁺-ATPase) was determined according to the procedure of Gallagher and Leonard (1982) (link), as modified by Sze (1985) . The reaction mixture contained 50 μg of protein (PM), 33 mM TRIS-MES (pH 7.5), 3 mM ATP, 2.5 mM MgSO₄, 50 mM KCl, 1 mM NaN₃, 0.1 mM Na₂MoO₄, and 50 mM NaNO₃, with or without 200 μM Na₃VO₄ and 0.02% Triton X-100. PM H⁺-ATPase activity was expressed as the difference between the activity measured in the absence and presence of Na₃VO_4. The amount of P_i released during the reaction was determined according to the method of Ames (1966) with 0.2% (w/v) SDS included to prevent precipitation (Dulley, 1975 (link)).
H⁺ transport activity was measured spectrophotometrically as the change in acridine orange absorbance at 495 nm (A₄₉₅) according to the method of Kłobus and Buczek (1995) . The assay medium contained PM vesicles (about 50 μg of protein), 25 mM BTP-MES (pH 7.5), 330 mM sorbitol, 50 mM KCl, 0.1% BSA, 10 μM acridine orange, and 0.05% Brij 58. Proton transport was initiated by the addition of 3 mM Mg-ATP. For every combination, passive proton movement through the membrane was determined without ATP in the reaction medium.
To evaluate expression of the genes encoding the PM H⁺-ATPase, CsHA2 (GenBank accession no. EU735752), CsHA3 (EF375892), CsHA4 (HO054960), CsHA8 (HO054964), CsHA9 (HO054965), and CsHA10 (HO054966), real-time PCR was performed using the LightCycler^® 2.0 system from Roche Diagnostics. For the normalization of expression of each CsHA gene, a gene encoding TIP41-like protein (GW881871) was used as the internal standard. Total RNA was isolated from 50 mg of frozen root tissue using Tri Reagent (Sigma) according to the manufacturer’s instructions. Total RNA yield was determined using a NanoDrop Spectrophotometer ND-1000 (Thermo Scientific) and the A_260/280 ratio showed the expected values between 1.9 and 2.0. To avoid any DNA contamination, the RNA samples were treated with RNase-free DNase I (Fermentas) and then reverse transcribed into first-strand cDNA using a High-Capacity cDNA Reverse Transcription Kit (Applied Biosystems) following the manufacturer’s instructions. The cDNA was then used as the template for PCR amplification with a RealTime 2× PCRMaster Mix SYBR^® (A&A Biotechnology) kit. The gene-specific primers used for PCR were carefully designed using the LightCycler Probe Design program. Expression of CsHAs was analysed with the following primer pairs: 5′-ACCCGAGTCGACAAACATCT-3′ (forward) and 5′-CTTGGCACAGCAAAGTGAAA-3′ (reverse) for CsHA2; 5′-AAGTTTCTGGGGTTCATGTGGAAT-3′ (forward) and 5′-GTAACAGGAAGTGACTCTCCAGTC-3′ (reverse) for CsHA3; 5′-CTACAGCTTGGTAACATACATTC-3′ (forward) and 5′-GTTGTAGTCCATGTAATGTCCTC-3′ (reverse) for CsHA4; 5′-CTCATGCGCAAAGAACATTAC-3′ (forward) and 5′-CTGAATTGTGTCAATGTCAAGTC-3′ (reverse) for CsHA8; 5′-AAACCAGAAGTGCTGGAG-3′ (forward) and 5′-CTCAGCACCCTCACTAGTAA-3′ (reverse) for CsHA9; 5′-GACATAATCAAGTTTGCAATCAGATA-3′ (forward) and 5′-TTCTGTATAAGTTGTGCGGT-3′ (reverse) for CsHA10; and 5′-CAACAGGTGATATTGGATTATGATTATAC-3′ (forward) and 5′-GCCAGCTCATCCTCATATAAG-3′ (reverse) for TIP41-like protein. The following amplifications conditions were applied: 30 s at 95 °C; 45 cycles of 10 s at 95 °C, 10 s at 58 °C, and 12 s at 72°C, and a final melting for 15 s at 65°C.
For Western blot analysis, 10 μg of PM protein was incubated in SDS buffer containing 2% (w/v) SDS, 80 mM dithiothreitol, 40% (w/v) glycerol, 5 mM PMSF, 10 mM Tris/HCl (pH 6.8), 1 mM EDTA, and 0.05% (w/v) bromophenol blue for 30 min at room temperature and separated by 7.5% SDS-PAGE (Laemmli, 1970 (link)). After 1 h of electrophoresis at 25 mA, the proteins were electrotransferred (60 V, 200 mA) for 1.5 h to nitrocellulose using an SV10-EB10 blotting apparatus (Sigma-Aldrich). The transfer buffer contained 25 mM Tris/HCl (pH 8.3), 150 mM glycine, and 10% (v/v) methanol.
To identify the PM H⁺-ATPase, the blots were incubated overnight (8 °C) with monoclonal antibody against PM H⁺-ATPase (46E5B11D, kindly provided by W. Michalke, Universität Freiburg, Germany). The antiserum was diluted 2000-fold. After repeated washing, the nitrocellulose membrane was incubated at room temperature for 1 h with 1:4000-diluted secondary antibody (anti-mouse, conjugated to horseradish peroxidase (HRP); Sigma-Aldrich) and visualized by staining with 3,3′-diaminobenzidine (DAB).
Phosphorylation of the PM H⁺-ATPase was detected with a rabbit polyclonal anti-phosphothreonine antibody (Abcam) used at a concentration of 2 μg/ml after overnight incubation (8 °C). The membranes were rinsed and incubated for 1 h at room temperature with 10 000-fold secondary antibody conjugated to HRP (polyclonal goat anti-rabbit IgG; Abcam). The results were visualized by staining with DAB.
Detection of 14-3-3 protein was performed with a rabbit polyclonal anti-14-3-3 antibody (Abcam). The antiserum was diluted 1000-fold. After overnight incubation (8 °C), the membranes were rinsed and incubated for 1 h at room temperature with 10 000-fold secondary antibody conjugated to HRP (polyclonal goat anti-rabbit IgG; Abcam). The results were visualized by staining with DAB.
Detection of HSPs was performed with rabbit polyclonal anti-HSP17.6, anti-HSP17.7, anti-HSP70, and anti-HSP101 (Agrisera). The antisera were diluted 500-, 1000-, 6000-, and 500-fold, respectively. After overnight incubation (8 °C), the membranes were rinsed and incubated for 1 h at room temperature with 6000-fold secondary antibody conjugated to HRP (polyclonal goat anti-rabbit IgG; Abcam). The results were visualized by staining with DAB.
The activity of PM oxidoreductase was assayed according to the method of Kłobus (1995) . Reduction of ferricyanide by NADH in PM vesicles was measured spectrophotometrically as the change in A₄₂₀. The assay medium contained PM vesicles (about 50 μg of protein), 25 mM BTP-Mes (pH 7.5), 250 mM sorbitol, 50 mM KCl, 3.75 mM MgSO₄, 0.5 mM NADH, 0.02% Triton X-100, and 0.5 mM K₃Fe(CN)_6.To measure H₂O₂ levels, 1 g of cucumber root was ground with a mortar and pestle in liquid nitrogen. Next, 3 ml of 50 mM Mops (pH 7.2) was added. Samples were centrifuged at 10 000 g for 10 min. The supernatant was used for measurement of H₂O₂. The reaction mixture contained 50 mM Mops, 0.2 μg/l of pyranine, 30 U/ml of peroxidase (VI-A; Sigma), and supernatant. The H₂O₂ level was determined fluorometrically (excitation at 405 nm and emission at 510 nm) using a TD-20/20 Fluorometer (Turner Designs).
Catalase (EC 1.11.1.6) activity was determined as described by Aebi (1984) (link). The decomposition of H₂O₂ was followed by measuring the decrease in A₂₄₀ for 150 s and was calculated per 60 s. The reaction mixture consisted of 50 mM phosphate buffer (pH 7.0), plant extract, and 10 mM H₂O₂. One unit of catalase is defined as the amount of enzyme that breaks down 1 μmol of H₂O₂/min.
Ascorbate peroxidase (APX) activity was determined in a mixture containing 100 mM potassium phosphate (pH 7.0), 0.5 mM ascorbate, 0.2 mM H₂O₂, and enzyme extract (Chen and Asada, 1989 ). Oxidation of ascorbate was followed by measuring the decrease in A₂₉₀. The conversion was assumed as the molar absorption coefficient value of 2.8 mM⁻¹ cm⁻¹.
Protein was measured according to the method of Bradford (1976) (link) in the presence of 0.02% Triton X-100 with BSA as the standard.
For each of at least three independent protein and RNA extractions, measurements of enzyme activity and gene expression were obtained in triplicate and the means ±SD of these values are presented in the figures. The quantitative PCR data were analysed by the ΔΔC_T method using LightCycler Software 4.1 (Roche).

Janicka-Russak M., Kabała K, & Burzyński M. (2012). Different effect of cadmium and copper on H+-ATPase activity in plasma membrane vesicles from Cucumis sativus roots. Journal of Experimental Botany, 63(11), 4133-4142.

Publication 2012

Evaluating pH Gradient Stability in LMVs

Cited 3 times

Pyranine is a pH sensitive probe that was used in this work to test the stability of the pH gradient in LMVs. The maximum absorption wavelengths for the acid (protonated) and the base (unprotonated) forms of pyranine are 405 nm and 450 nm, respectively⁵¹. The fluorescence intensity of pyranine excited at 450 nm is high at pH 7-8 but near background at acidic pH, while the inverse is true for the fluorescence produced by 405 nm excitation^{52 (link)}. Ratiometric measurements using an excitation ratio of 450/405 nm are for that reason frequently used to provide information about the pH of a determined solution. This is an advantageous method since it not depends on pyranine concentration and is directly related with pyranine ionization degree.
LMVs/LUVs with 3 mM total lipid concentration were prepared using Hepes or Citrate Phosphate buffer (pH 7.4 or pH 5.0, respectively), as above described. These vesicles contained 0.5 mM pyranine encapsulated^{35 (link)}. The following (POPC/SM/Chol ternary mixtures were used: 59.7:26.3:14 (Xl_o = 26) and 34:32.7:33.3 (Xl_o = 0.83). Liposomes encapsulating pyranine were recovered (after separation through a Sephadex G-25 column) mainly in fractions 3 and 4 (1 mL each). Liposome final concentration was determined by lipid phosphorous analysis^{50 (link)}, for the samples prepared in Hepes buffer. The liposomes were then diluted to approximately 0.2 mM lipid concentration in 96 well opaque plates and fluorescence measurements were performed at 24 °C, in a microplate reader (Spectramax Gemini EM), using 405 and 450 nm as the excitation wavelengths and 510 nm as emission wavelength. The auto mix option of the microplate reader was selected to mix the samples 5 seconds before the first read and 3 seconds between reads. To evaluate the stability of the pH gradient in LMVs, the fluorescence measurements were performed during ap. 5 hours. After this time, triton X100 (0.1% (v/v)) was added to the samples in order to obtain the fluorescence intensity induced by an immediate burst of the vesicles. Some of the wells with LMVs (without the addition of triton X100) were left overnight and measurements were also performed next day, to observe if the pH gradient remained stable. No significant changes were observed (data not shown). Samples with acidic and neutral pH both inside and outside the vesicles were prepared to obtain the fluorescence intensity of pyranine at only acidic and neutral conditions (control samples). The stability of the LMVs was evaluated in the absence and presence of Sph (pre-incorporation of 10 mol% Sph and external addition of 10 mol% Sph). In the studies where Sph is externally added, Sph was dissolved in a small volume of absolute ethanol (ethanol was kept below to 1% v/v to prevent vesicle destabilization) and added to lipid vesicle suspensions (the auto mix option of the microplate reader was selected to mix the samples 5 seconds before the first read and 3 seconds between reads). Control experiments were also performed by adding the same volume of ethanol, without Sph.

Carreira A.C., de Almeida R.F, & Silva L.C. (2017). Development of lysosome-mimicking vesicles to study the effect of abnormal accumulation of sphingosine on membrane properties. Scientific Reports, 7, 3949.

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Publication 2017

Acids Buffers Citrates Ethanol Fluorescence HEPES Lipids Liposomes Neoplasm Metastasis Phosphates Phosphorus pyranine sephadex G 25 Triton X-100

Ambient pH Imaging of Foraminifera

Cited 3 times

For ambient pH imaging, pH indicator HPTS (pyranine 8-Hydroxypyrene-1,3,6-trisulfonic acid trisodium salt, H1529, Sigma-Aldrich) was dissolved to a final concentration of 20 μM20 . This concentration of HPTS is known to be harmless to foraminiferal behaviour and does not noticeably impair their calcification process20 . Total alkalinity of the solution is determined by pH method40 41 . The observations were carried out with ten individuals under various pH/pCO₂ conditions. Individuals were incubated in the solution for 10 min before starting observations under room temperature (∼23 °C). The individuals were then observed under an inverted fluorescent microscope (Zeiss Axio Observer Z1, Germany).
Three individuals were additionally incubated with Bafilomycin A₁, a V-type H⁺ ATPase inhibitor (BVT-0252, BioViotica). These incubations were done to investigate the influence of H⁺ ATPases on calcification (see similar approach in scleractinian corals22 (link)). Bafilomycin A₁ was dissolved to a final concentration of 1 μM in seawater with 20 μM HTPS42 (link). The specimens were placed in the solution only during chamber formation. All three specimens were observed trying to form a new chamber in the presence of Bafilomycin A₁.

Toyofuku T., Matsuo M.Y., de Nooijer L.J., Nagai Y., Kawada S., Fujita K., Reichart G.J., Nomaki H., Tsuchiya M., Sakaguchi H, & Kitazato H. (2017). Proton pumping accompanies calcification in foraminifera. Nature Communications, 8, 14145.

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Publication 2017

Acids Alkalies bafilomycin A1 Foraminifera Microscopy Physiologic Calcification Proton-Translocating ATPases pyranine Sodium Chloride Vacuolar H+-ATPase

Reconstitution and Proton Uptake of UCP1

Cited 2 times

The reconstitution of UCP1 and measurement of proton uptake activity were carried out following the methods of Echtay et al. (39 (link)). 20 μg of Fos12-solubilized UCP1 inclusion body material or native UCP1 in 10MNG was reconstituted into phosphatidylcholine (18:1) liposomes loaded with 100 mm K⁺ (potassium phosphate, pH 7.5) and 0.2 mm EDTA and exchanged into external buffer (110 mm sucrose, 1 mm K⁺ (gluconate), 0.5 mm Hepes, pH 7.5). Proton uptake was measured by following the pH-sensitive fluorescence of external pyranine (λ_ex = 467 nm, λ_em = 510 nm) at 25 °C. 75 μl of proteoliposomes were diluted to 500 μl in external buffer (pH 8.2) containing 1 μm pyranine, 200 μm oleic acid (1.6 mm methyl-β-cyclodextrin), and 40 μm GDP where indicated. The fluorescent signal of the sample was adjusted to pH 7.5 with 7.5 mm H₂SO₄ in 30-nmol H⁺ steps to calibrate the signal/proton change. A membrane potential was induced by the addition of 2.5 μm valinomycin to drive proton uptake, and the total proton uptake capacity of the system was revealed through the subsequent addition of 1 μm carbonyl cyanide p-chlorophenylhydrazone. Initial rates of proton uptake were estimated from fits of the valinomycin-induced progress curve using an appropriate exponential function (“plateau and one phase association”; GraphPad Prism software).

Crichton P.G., Lee Y., Ruprecht J.J., Cerson E., Thangaratnarajah C., King M.S, & Kunji E.R. (2015). Trends in Thermostability Provide Information on the Nature of Substrate, Inhibitor, and Lipid Interactions with Mitochondrial Carriers. The Journal of Biological Chemistry, 290(13), 8206-8217.

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Publication 2015

Buffers Cyclodextrins Edetic Acid Fluorescence gluconate HEPES Inclusion Bodies Liposomes Membrane Potentials mesoxalonitrile Oleic Acid Phosphatidylcholines potassium phosphate prisma proteoliposomes Protons pyranine Seizures Sucrose UCP1 protein, human Valinomycin

Lipid Composition Analysis Protocol

Cited 2 times

Sph, POPC and SM from Egg, Chicken were obtained from Avanti Polar Lipids, Inc. (Alabaster, AL, USA). Chol and TX-100 were obtained from Sigma-Aldrich (St. Louis, MO, USA). trans-parinaric acid (t-PnA) and pyranine were purchased from Molecular Probes/Invitrogen (Eugene, OR, USA). 8-Aminonaphthalene-1,3,6-Trisulfonic Acid, Disodium Salt (ANTS) and p-xylene-bis-pyridinium bromide (DPX) were supplied by Life Technologies (Carlsbad, CA, USA). The organic solvents were obtained from Fluka (St. Louis, MO, USA).
The concentration of the lipid and of the probes stock solutions were determined as previously described^{26 (link)}.

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Publication 2017

1-Naphthylamine 4-xylene Acids Alabaster Ants Bromides Chickens Lipids Molecular Probes parinaric acid polyethylene glycol monooctylphenyl ether pyranine Sodium Chloride Solvents

Most recents protocols related to «Pyranine»

Pyranine Functionalization via Methallyl Chloride

Not available on PMC !

Example 1

548.7 g Keystone™ liquid pyranine solution and 100.1 g of methanol were charged to a 1 L multi-neck round bottom flask equipped with mechanical agitator, thermocouple, methallyl chloride dosing line, NaOH 50% dosing line, and condenser. The mixture was heated to 70° C. and upon reaching the reaction temperature slow additions of methallyl chloride and NaOH 50% were begun. The reaction mixture was refluxed at 70-72° C. during the addition. The methallyl chloride was added over 4 hours while the 50% NaOH was added over 6 hr period, for addition rates of about 7 g/hr and 5 g/hr, respectively. After addition of the NaOH, 50% solution was complete, the reaction mixture was held at 70° C. for 2 more hours. The methanol was removed by distillation at 70-75° C. under nitrogen sparging. Approximately 120 g of distillate was removed.

Table 1 summarizes the material balance of the initial reaction mixture.

TABLE 1

Material balance

MaterialWt (g)Wt %(g/eq)moles

Pyranine solution548.778.012280.000.241

(assume 23%)

NaOH, 50%25.63.64800.320

Methallyl chloride29.04.1290.550.320

Methanol100.114.23——

Total703.4100.0

Table 2 sets forth the composition of the reaction product after distillation, as determined by NMR.

TABLE 2

Percentage Composition of Example 1 Reaction Product

Reaction Product

ComponentMole %Weight %

methallyl oxy pyranine82.387.1

methallyl pyranine9.810.3

Unreacted Pyranine1.41.5

Methallyl Alcohol3.30.4

Dimethallyl Ether3.20.7

The unfunctionalized pyranine content was 1.4 mol % of the total moles of unfunctionalized pyranine, methallyl oxy pyranine and methallyl pyranine.

US11859026B2. Water soluble pyranine polymers and method of making (2024-01-02). NOURYON CHEMICALS INTERNATIONAL B.V. [NL]. Inventors: Klin Aloysius Rodrigues [US], Andrew James Bailey [US], Jobie Lebron Jones [US], Wyatt August Winkenwerder [US], Elliot Isaac Band [US].

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Patent 2024

Proteoliposome Reconstitution and Membrane Potential Measurement

Proteoliposomes were reconstituted with an internal buffer of 25 mM HEPES, pH 7.53, 100 mM NaCl, 100 mM KCl, and preloaded with 0.4 mM substrate (Gdm⁺ or guanylurea) and 1 mM pyranine (trisodium 8-hydroxypyrene-1, 3, 6-trisulfonate; Sigma-Aldrich) using three freeze/thaw cycles. Unilamellar liposomes were formed by extrusion through a 400-nm membrane filter and the external pyranine was removed by passing liposomes through a Sephadex G-50 column spin column equilibrated in an internal buffer with substrate. The external assay buffers contained 25 mM HEPES, pH 7.53, 0.4 mM substrate, and varying KCl concentration (3–46 mM) to establish the membrane potential, with NaCl to bring the total salt concentration to 200 mM. Proteoliposomes were diluted 200-fold into the external buffer, and after ∼30 s to establish a baseline, valinomycin (final concentration 0.2 ng/ml) was added together with the substrate (final concentration 4 mM). Fluorescence spectra were monitored (λ_ex = 455 nm; λ_em = 515 nm) for ∼300 s. The membrane potential was calculated using the Nernst potential for K⁺:

ψ_{c a l c} = \frac{R T}{F} \ln \frac{{[K^{+}]}_{o u t}}{{[K^{+}]}_{i n}} .

Fluorescence emission time courses were corrected for baseline drift measured prior to substrate and valinomycin addition. The stoichiometry was determined from the voltage at which electrochemical equilibrium occurred (no change in fluorescence over time) using the following equation:

E_{r e v} = (\frac{n}{m - n} * \frac{R T}{F} \ln \frac{{[s u b s t r a t e^{+}]}_{i n}}{{[s u b s t r a t e^{+}]}_{o u t}}),

where n and m represent the stoichiometric coefficients of substrate and protons, respectively.

Lucero R.M., Demirer K., Yeh T.J, & Stockbridge R.B. (2024). Transport of metformin metabolites by guanidinium exporters of the small multidrug resistance family. The Journal of General Physiology, 156(3), e202313464.

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Publication 2024

Fluorescent Pyranine Functionalization and Polymer Evaluation

Not available on PMC !

Example 2

548.7 g Keystone™ liquid pyranine solution and 100.1 g of 1-propanol were charged to a 1 L multi-neck round bottom flask equipped with mechanical agitator, thermocouple, methallyl chloride dosing line, NaOH, 50% dosing line, and condenser. The mixture was heated to 70° C. and upon reaching the reaction temperature slow additions of methallyl chloride and NaOH, 50% were begun. The reaction mixture was refluxed at 70-72° C. during the addition. The methallyl chloride was added over 4 hours while the 50% NaOH was added over 6 hr period. After completion of the NaOH, 50% addition, the reaction mixture was held at 70° C. for 2 more hours. No distillation or other isolation steps were performed on the reaction product.

Table 3 summarizes the material balance of the initial reaction mixture.

TABLE 3

Material balance

MaterialWt (g)Wt %(g/eq)moles

Pyranine solution548.778.012280.000.241

(calculated as 23%)*

NaOH, 50%25.63.64800.320

Methallyl chloride29.04.1290.550.320

1-propanol100.114.23——

Total703.4100.0

*Pyranine solution as supplied is 19-23% pyranine

Table 4 sets forth the composition of the reaction product as determined by NMR.

TABLE 4

Composition of Example 2 Reaction product

Reaction Product

ComponentMole %Weight %

methallyloxy pyranine52.281.5

methallyl pyranine6.19.5

Methallyl Alcohol34.86.8

Dimethallyl Ether2.80.9

2-methyl-3-propoxyprop-1-ene4.21.3

No unfunctionalized pyranine was detected by NMR. The unfunctionalized pyranine content was 0.11 wt % of the final solution as determined by LC. The unfunctionalized pyranine content was 0.55 wt % (0.61 mol %) of the total of pyranine, methallyl oxy pyranine and methallyl pyranine.

Example 3

Example 2 was repeated, but 2-propanol was used instead of 1-propanol. The unfunctionalized pyranine content was 0.50 wt % (0.55 mol %) of the total of unfunctionalized pyranine, methallyl oxy pyranine and methallyl pyranine, as determined by NMR.

Example 5

247 g of water was added to a round bottom flask. Next, 66.1 g of maleic anhydride was added with stirring. 27 g of 50% sodium hydroxide was then added along with 0.0616 g of ferrous ammonium sulfate hexahydrate. The initial charge was heated to 85° C. A monomer mixture containing 125.3 g of acrylic acid, 11.9 g of methyl methacrylate, 74 g of AMPS 2403 from Lubrizol (50% AMPS) and 22.5 g of the liquid reaction product from Example 2, (which contains 1.88 g of methallyl oxy pyranine, 0.1 mole percent of the monomer mixture) was added over 4 hours. Simultaneously, an initiator solution containing 15.3 g of sodium persulfate, 50.9 g of 35% hydrogen peroxide dissolved in 25 g of water was added over the same period of 4 hours. The reaction mixture was held for one hour at 85° C. The reaction mixture was then cooled down to room temperature and 50.4 g of 50% sodium hydroxide was added. The polymer solution contained approximately 40% polymer solids and a pH of 4.5.

Example 6

Pyranine solution, 19-23% in water (553.9 g, Milikin), 1-propanol (100.0 g) and sodium hydroxide, 50% (25.88 g) were charged to a 1-L multi-neck round bottom flask equipped with mechanical agitator, thermocouple, methallyl chloride dosing line, and condenser. The mixture was heated to 70° C. and upon reaching the reaction temperature a flow of methallyl chloride begun (0.13 mL/min, 247 minutes, 34.71 g) and the reaction mixture refluxed at 70-72° C. during the addition. After completion of the methallyl chloride addition, the mixture was digested for a 4 hr period at 70° C. The reaction mixture was cooled and discharged (700 g). Table 6 summarizes the material balance and Table 7 the analysis of the sample compared to the sample made by co-dosing the sodium hydroxide and methallyl chloride to the pyranine solution.

TABLE 6

Material balance of Example 6

MaterialWt(g)Wt %(g/eq)moles

Pyranine solution, 19-23%553.978.072280.000.243

NaOH, 50%25.93.65800.324

Methallyl chloride29.74.1890.550.328

1-propanol100.014.09——

TABLE 7

NMR analysis of co-dosing process

Ex. 6Ex. 6

(NaOH(NaOH

addedaddedEx. 2Ex. 2

upfront)upfront)(co-dosing)(co-dosing)

ComponentWeight %Mole %Weight %Mole %

methallyl oxy79.148.481.552.2

Pyranine

Unreacted1.61.1NDND

Pyranine

Methallyl8.039.06.834.8

Alcohol

Dimethallyl0.72.10.92.8

Ether

methallyl9.55.89.55.8

Pyranine

2-methyl-3-1.23.61.34.2

propoxyprop-1-ene

As seen in Table 7, the co-dosing method gives higher amounts of pyranine reaction product along with reducing the amount of unreacted pyranine to below the detection limit of NMR of ˜1 mol %. A higher rate of methallyl alcohol formation is likely the cause of the lower conversion for the process in which the NaOH is added upfront. This hypothesis is supported by the higher amount of methallyl alcohol seen in the NMR analysis. The method of Example 2 achieved higher conversion of pyranine to polymerizable monomers than the method of Example 6.

Example 7

An initial charge of 248 g deionized water and 66 g of maleic anhydride was added to a 1-liter glass reactor with inlet ports for an agitator, water cooled condenser, thermocouple, and adapters for the addition of monomer and initiator solutions. The reactor contents were heated 85° C. 27 g of 50% sodium hydroxide and 0.0616 g of ferrous ammonium sulfate hexahydrate was added. A mixed monomer solution which consisted of 125.5 g of acrylic acid, 11.9 g of methyl methacrylate, 74.3 g of AMPS 2403 (50% solution of sodium AMPS from Lubrizol) 8.13 g of the monomer solution from Example 2 was fed to the reactor via measured slow-addition with stirring over a period of 4 hours. An initiator solution of 50.9 g of 35% hydrogen peroxide, 15.2 grams sodium persulfate dissolved in 25 grams water was concurrently added, starting at the same time as the monomer solution, for a period of 4 hours. The reaction product was then held at 85° C. for 30 minutes. Next, 0.36 g of erythorbic acid dissolved in 3 g of water was added. Immediately after that, 0.36 g of tertiary butyl hydroperoxide, 70% solution dissolved in 3 g of water was added. The reaction mixture was then heated at 85° C. for 1 hour. The polymers partially neutralized with 50.4 g of 50% sodium hydroxide. The final reaction mixture was an amber colored solution with a solids of about 40%, and a pH of 4.4.

Example 8

An initial charge of 248 g deionized water and 66 g of maleic anhydride was added to a 1-liter glass reactor with inlet ports for an agitator, water cooled condenser, thermocouple, and adapters for the addition of monomer and initiator solutions. The reactor contents were heated 85° C. 27 g of 50% sodium hydroxide and 0.0616 g of ferrous ammonium sulfate hexahydrate was added. A mixed monomer solution which consisted of 125.5 g of acrylic acid, 11.9 g of methyl methacrylate, 74.3 g of AMPS 2403 (50% solution of sodium AMPS from Lubrizol) 22.35 g of the monomer solution from Example 2 was fed to the reactor via measured slow-addition with stirring over a period of 4 hours. An initiator solution of 50.9 g of 35% hydrogen peroxide, 15.2 grams sodium persulfate dissolved in 25 grams water was concurrently added, starting at the same time as the monomer solution, for a period of 4 hours. The reaction product was then held at 85° C. for 30 minutes. Next, 0.36 g of erythorbic acid dissolved in 3 g of water was added. Immediately after that, 0.36 g of tertiary butyl hydroperoxide, 70% solution dissolved in 3 g of water was added. The reaction mixture was then heated at 85° C. for 1 hour. The polymers partially neutralized with 50.4 g of 50% sodium hydroxide. The final reaction mixture was an amber colored solution with a solids of about 40%, and a pH of 4.4.

Example 9

Various water treatment polymers were evaluated for their ability to prevent the precipitation of calcium carbonate in typical cooling water conditions, a property commonly referred to as the threshold inhibition. Solutions were prepared in which the ratio of calcium concentration to alkalinity was 1.000:1.448 to simulate typical conditions in industrial water systems used for cooling. Generally, water wherein the alkalinity is proportionately less will be able to reach higher levels of calcium, and water containing a proportionally greater amount of alkalinity will reach lower levels of calcium. Since cycle of concentration is a general term, one cycle was chosen, in this case, to be that level at which calcium concentrations equaled 100.0 mg/L Ca as CaCO₃(40.0 mg/L as Ca). The complete water conditions at one cycle of concentration (i.e., make-up water conditions) were as follows:

Simulated Make-Up Water Conditions:

- 100.00 mg/L Ca as CaCO₃(40.0 mg/L as Ca) (one cycle of concentration)
- 49.20 mg/L Mg as CaCO₃(12.0 mg/L as Mg)
- 2.88 mg/L Li as CaCO₃(0.4 mg/L Li as Li)
- 144.80 M Alkalinity (144.0 mg/L as HCO₃)
- 13.40 P Alkalinity (16.0 mg/L as CO₃)

In dynamic testing, where the pH is about 8.80, bulk water temperature is around 104° F., flow is approximately 3.0 m/s, and heat transfer is approximately 17,000 BTU/hr/ft², above average threshold inhibitors can reach anywhere from four to five cycles of concentration with this water before significant calcium carbonate precipitation begins. Average threshold inhibitors may only be able to reach three to four cycles of concentration before precipitating, while below average inhibitors may only reach two to three cycles of concentration before precipitation occurs.

Polymer performance is generally expressed as percent calcium inhibition. This number is calculated by taking the actual soluble calcium concentration at any given cycle, dividing it by the intended soluble calcium concentration for that same given cycle, and then multiplying the result by 100. Resulting percentage amounts that are below 90% calcium inhibition are considered to be indicators of a significant precipitation of calcium carbonate. However, there are two ways in which an inhibitor can react once the threshold limit is reached. Some lose practically all of their calcium carbonate threshold inhibition properties, falling from 90-100% to below 25% threshold inhibition. Others are able to “hold on” better to their inhibition properties, maintaining anywhere from 50% to 80% threshold inhibition.

Testing beyond the threshold limit in order to determine each inhibitor's ability to “hold on” has been found to be a better method of predicting an inhibitor's ability to prevent the formation of calcium carbonate in the dynamic testing units. It also allows for greater differentiation in test results. Therefore, a higher cycle (4.0 cycles) was chosen for this test. At this concentration, above average inhibitors should be expected to give better than 60% threshold inhibition. Poor inhibitors should be expected to give less than 20% threshold inhibition, while average inhibitors should fall somewhere in between.

Materials:

- One incubator/shaker, containing a 125 mL flask platform, with 34 flask capacity
- 34 Screw-cap Erlenmeyer Flasks (125 mL)
- 1 Brinkmann Dispensette (100 mL)
- Deionized Water
- Electronic pipette(s) capable of dispensing between 0.0 mL and 2.5 mL
- 250 Cycle Hardness Solution*
- 10,000 mg/L treatment solutions, prepared using known active solids of the desired treatment*
- 10% and 50% solutions of NaOH
- 250 Cycle Alkalinity Solution*
- 0.2 μm syringe filters or 0.2 μm filter membranes
- 34 Volumetric Flasks (100 mL)
- Concentrated Nitric Acid * See solution preparations in next section.

Solution Preparations:

All chemicals used were reagent grade and weighed on an analytical balance to ±0.0005 g of the indicated value. All solutions were made within thirty days of testing. The hardness, alkalinity, and 12% KCl solutions were prepared in a one liter volumetric flask using DI water. The following amounts of chemical were used to prepare these solutions—

250 Cycle Hardness Solution:

- 10,000 mg/L Ca⇒36.6838 g CaCl₂·2H₂O
- 3,000 mg/L Mg⇒25.0836 g MgCl₂·6H₂O
- 100 mg/L⇒Li 0.6127 g LiCl

250 Cycle Alkalinity Solution:

- 36,000 mg/L HCO₃⇒48.9863 g NaHCO₃
- 4,000 mg/L CO₃⇒7.0659 g Na₂CO₃

10,000 mg/L Treatment Solutions:

Using percentage of active product in the supplied treatment, 250 mL of a 10,000 mg/L active treatment solution was made up for every treatment tested. The pH of the solutions was adjusted to between 8.70 and 8.90 using 50% and 10% NaOH solutions by adding the weighed polymer into a specimen cup or beaker and filling with DI water to approximately 90 mL. The pH of this solution was then adjusted to approximately 8.70 by first adding the 50% NaOH solution until the pH reached 8.00, and then by using the 10% NaOH until the pH equaled 8.70. The solution was then poured into a 250 mL volumetric flask. The specimen cup or beaker was rinsed with DI water and this water was added to the flask until the final 250 mL was reached. The amount of treatment product to be weighed was calculated as follows:

$Grams of treatment needed = \frac{(10,000 mg / L) (0.25 L)}{(decimal % of active treatment) (1000 mg)}$

Test Setup Procedure:

The incubator shaker was turned on and set for a temperature of 50° C. to preheat. 34 screw cap flasks were set out in groups of three to allow for triplicate testing of each treatment, allowing for testing of eleven different treatments. The one remaining flask was used as an untreated blank.

The Brinkmann dispensette was calibrated to deliver 96.6 mL, using DI water, by placing a specimen cup or beaker on an electronic balance and dispensing the water into the container for weighing. The dispensette was adjusted accordingly, until a weight of 96.5-96.7 g DI water was delivered. This weight was recorded, the procedure was repeated for a total of three measurements, and the average determined. Once calibrated, 96.6 mL DI water was dispensed into each flask.

Using a 2.5 mL electric pipette, 1.60 mL of hardness solution was added to each flask to simulate four cycles of make-up water.

Using a 250 μL electronic pipette, 200 μL of desired treatment solution were added to each flask to achieve a 20 mg/L active treatment dosage. A new tip on the electric pipette was used for each treatment solution so cross contamination did not occur.

Using a 2.5 mL electric pipette, 1.60 mL of alkalinity solution was added to each flask to simulate four cycles of make-up water. The addition of alkalinity was done while swirling the flask, so as not to generate premature scale formation from high alkalinity concentration pooling at the addition site.

One “blank” solution was prepared in the exact same manner as the above treated solutions, except DI water was added in place of the treatment solution.

All 34 flasks uncapped were placed onto the shaker platform and the door closed. The shaker was run at 250 rpm and 50° C. for 17 hours.

A “total” solution was prepared in the exact same manner as the above treated solutions were prepared, except that DI water was used in place of both the treatment solution and alkalinity solution. This solution was capped and left overnight outside the shaker.

Test Analysis Procedure:

Once 17 hours had passed, the 34 flasks were removed from the shaker and allowed to cool for one hour. Each flask solution was filtered through a 0.2 μm filter membrane. The filtrate was analyzed directly for lithium, calcium, and magnesium concentrations by either an Inductively Couple Plasma (ICP) Optical Emission System or Flame Atomic Absorption (AA) system. The “total” solution was analyzed in the same manner.

Calculations of Results:

Once the lithium, calcium, and magnesium concentrations were known in all 34 shaker samples and in the “total” solution, the percent inhibition was calculated for each treatment. The lithium was used as a tracer of evaporation in each flask (typically about ten percent of the original volume). The lithium concentration found in the “total” solution was assumed to be the starting concentration in all 34 flasks. The concentrations of lithium in the 34 shaker samples were each divided by the lithium concentration found in the “total” sample. These results provided the multiplying factor for increases in concentration, due to evaporation. The calcium and magnesium concentrations found in the “total” solution were also assumed to be the starting concentrations in all 34 flasks. By multiplying these concentrations by each calculated evaporation factor for each shaker sample, the final intended calcium and magnesium concentration for each shaker sample was determined. By subtracting the calcium and magnesium concentrations of the “blank” from both the actual and intended concentrations of calcium and magnesium, then dividing the resulting actual concentration by the resulting intended concentration and multiplying by 100, the percent inhibition for each treated sample was calculated. The triplicate treatments were averaged to provide more accurate results.

Example:

“Total” concentration analysis results:

- Li=1.61 mg/L
- Ca=158.0 mg/L
- Mg=50.0 mg/L

“Blank” concentration analysis results:

- Li=1.78 mg/L
- Ca=4.1 mg/L
- Mg=49.1 mg/L

Shaker sample concentration analysis results:

- Li=1.78 mg/L
- Ca=150.0 mg/L
- Mg=54.0 mg/L

By taking the Li concentration from the shaker sample and dividing by the Li concentration in the “total” sample, the evaporation factor was determined as—
⇒1.78 mg/L/1.61 mg/L=1.11

By multiplying the Ca and Mg concentrations in the “total” sample by this factor, the final intended concentrations of Ca and Mg in the shaker sample were determined as—
Ca⇒1.11×158.0 mg/L=175.4 mg/L CaMg⇒1.11×50.0 mg/L=55.5 mg/L Mg

Finally, by subtracting the calcium and magnesium concentrations of the “blank” from both the actual and intended concentrations of calcium and magnesium, then dividing the resulting actual concentrations of Ca and Mg in the shaker sample by the resulting final intended concentrations and multiplying by 100, the percent threshold inhibition of calcium and magnesium was calculated as—
Ca⇒((150.0 mg/L−4.1 mg/L)/(175.4 mg/L−4.1 mg/L))×100=85.2% Ca inhibitionMg⇒((54.0 mg/L−49.1 mg/L)/(55.5 mg/L−49.1 mg/L))×100=76.6% Mg inhibition

The polymers of Example 7 and 8 were tested according to the procedure outlined above.

TABLE 8

percent calcium carbonate inhibition

%%%%

inhibitioninhibitioninhibitioninhibition

Polymerat 2 ppmat 3 ppmat 4 ppmat 5 ppm

Example 7618792

Example 88799100

Polymer of567594100

Example 7

without

fluorescent

tag

In the test above, anything above 80% inhibition is considered acceptable. These data in Table 8 indicate that the carbonate inhibition performance of the polymer is the same with the fluorescent tag as it is without the tag, indicating that the presence of the tag does not interfere with the primary purpose of the polymer which is scale minimization.

The specific examples herein disclosed are to be considered as being primarily illustrative. Various changes beyond those described will, no doubt, occur to those skilled in the art; and such changes are to be understood as forming a part of this invention insofar as they fall within the spirit and scope of the appended claims.

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Patent 2024

Synthesis of Allyl-Functionalized Pyranine

Not available on PMC !

Example 4

A quantity of the Keystone™ pyranine solution was dried in an oven at 60° C. over a 24 hour period to remove the water. Under a nitrogen atmosphere, the dried pyranine (solid, 2.62 g, 5.0 mmol) was added to dry DMSO (25 mL) along with NaOH, 50% (0.48 g, 6.0 mmol) and stirred at room temperature for a 30 minute period. Not all of the pyranine was dissolved after 30 minutes. However, following Monomer Example II of U.S. Pat. No. 6,312,644, allyl chloride (0.4831 g, 6.31 mmol) was added to the mixture in a single addition. The reaction mixture was stirred for a 6-hr period at room temperature. The next day the reaction mixture was filtered through a glass filter into a 100-mL round bottom flask; the solid filtered material was assumed to be sodium chloride. The majority of DMSO was removed by rotary evaporation (80 C, 7 Torr). The residue was washed with 100 mL of acetone for a 3-hr period which caused an insoluble solid to precipitate. The solid was filtered, collected and dried at room temperature to remove residual acetone. Only 1.0 g of solid was collected from the reaction. Analysis of the solid by NMR (D₂O solvent) is reported in Table 5. No alkylation product was detected by NMR.

TABLE 5

Composition of Example 4 Reaction Product

Example 4

ComponentMole %Weight %

Allyl oxypyranine91.091.6

Unreacted Pyranine9.08.4

It was determined by liquid chromatography that the sample contained unreacted pyranine at a concentration of 80 mg/g, or 8 wt % or 9 mole %.

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Patent 2024

Acetone Alkylation allyl chloride Atmosphere Liquid Chromatography Moles Nitrogen pyranine Sodium Chloride Solvents Sulfoxide, Dimethyl

Proton Transport by Lugdunin Analogs

Proton transport induced by lugdunin and its analogs was analyzed using the pH-sensitive dye pyranine (8-hydroxypyrene-1,3,6-trisulfonic acid). LUVs were filled with 100 mm KCl, 10 mm HEPES, and 0.5 mm pyranine (pH = 7.4), and extravesicular dye was removed after extrusion via size exclusion chromatography (Illustra NAP-25 G25, GE Healthcare, Chalfont St Giles, UK). The vesicles were diluted in the same buffer without pyranine and pH = 6.4 to a final lipid concentration of 50 µm. Pyranine fluorescence was monitored in a time-dependent manner with λ_ex = 458 nm, λ_em = 512 nm, and band widths of 3 nm using an FP 6500 spectrofluorometer (Jasco Germany, Groß-Umstadt, Germany; Spectra Manager V. 1.54.03) under constant stirring. After acquiring a baseline for 100 s, peptide stock solution in isopropanol was added to a nominal peptide-to-lipid ratio (n/n) of 1:250. Acidification of the lumen resulted in fluorescent quenching and was monitored over the course of 500 s. Afterward, the vesicles were lysed by the addition of N,N-dimethyl-n-dodecylamine N-oxide (LDAO) leading to a disruption of the pH gradient. All data points were normalized to the fluorescence intensity directly before the addition of the peptide and after vesicle lysis.

Ruppelt D., Trollmann M.F., Dema T., Wirtz S.N., Flegel H., Mönnikes S., Grond S., Böckmann R.A, & Steinem C. (2024). The antimicrobial fibupeptide lugdunin forms water-filled channel structures in lipid membranes. Nature Communications, 15, 3521.

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Publication 2024

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Pyranine is a fluorescent dye used in various laboratory applications. It functions as a pH indicator, excitable at 340-400 nm and emitting at 505-520 nm.

What are some common applications of Pyranine?

Pyranine is a versatile fluorescent dye used in a variety of applications in biological research. It is commonly used as a pH indicator to monitor intracellular pH changes, as a tracer in hydrological studies, and as a probe for cell and tissue imaging. Pyranine's water-soluble and pH-sensitive properties make it a valuable tool for researchers studying cellular processes and environmental dynamics.

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Are there different types or variations of Pyranine?

Yes, there are several different variations of Pyranine, including sulfonated, carboxylated, and ester forms. These variations can have slightly different properties, such as excitation/emission wavelengths, pH sensitivity, and solubility characteristics. Researchers should choose the Pyranine form that best suits their specific application and experimental requirements. PubCompare.ai can help researchers compare the different Pyranine variants and select the most appropriate one for their research.

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More about "Pyranine"

Pyranine is a versatile fluorescent dye commonly used in biological research.
It is a water-soluble, pH-sensitive compound that emits bright green fluorescence when excited by ultraviolet light.
Pyranine has been widely used in a variety of applications, including as a tracer in hydrological studies, a pH indicator in cell and tissue imaging, and a probe for monitoring intracellular pH changes.
Researchers can optimize their Pyranine protocols using PubCompare.ai's AI-driven platform, which helps locate the best procedures from literature, preprints, and patents through intelligent comparisons.
This streamlines the research process and allows scientists to find the most effective Pyranine protocolls with cutting-edge technology.
Pyranine, also known as FP-6500 or 8-hydroxypyrene-1,3,6-trisulfonic acid trisodium salt, is often used in combination with other fluorescent dyes, such as 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (DiI) and Calcein, to study various biological processes.
It can also be used in conjunction with lipids like 1,2-dioleoyl-sn-glycero-3-phosphocholine and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine to investigate membrane dynamics and interactions.
The SpectraMax M2 is a common instrument used to measure Pyranine fluorescence, allowing researchers to quantify and analyze pH-dependent changes in their experiments.
Additionally, Pyranine has been utilized in studies involving ovalbumin (OVA), a protein commonly used as a model antigen in immunological research.
By leveraging the insights and tools provided by PubCompare.ai, researchers can streamline their Pyranine-based experiments, optimizing protocols and accessing the latest advancements in the field.
This ensures that scientists can efficiently and effectively utilize this versatile fluorescent dye to advance their biological research.