scholarly journals Optical pH Sensor Based on Immobilization Anthocyanin from Dioscorea alata L. onto Polyelectrolyte Complex Pectin–Chitosan Membrane for a Determination Method of Salivary pH

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1276
Author(s):  
Eka Safitri ◽  
Hani Humaira ◽  
Murniana Murniana ◽  
Nazaruddin Nazaruddin ◽  
Muhammad Iqhrammullah ◽  
...  
Keyword(s):  
Polyelectrolyte Complex ◽  
Ph Sensor ◽  
Dioscorea Alata ◽  
Anthocyanin Content ◽  
Buffer Solution ◽  
Citrate Buffer ◽  
Relative Standard ◽  
Significant Difference ◽  
Salivary Ph ◽  
Optical Ph Sensor

A simple optical pH sensor based on immobilization, Dioscorea alata L. anthocyanin methanol extract, onto a pectin–chitosan polyelectrolyte complex (pectin–chitosan PEC), has been successfully fabricated. The optical pH sensor was manufactured as a membrane made of pectin–chitosan PEC and the extracted anthocyanin. This sensor has the highest sensitivity of anthocyanin content at 0.025 mg/L in phosphate buffer and 0.0375 mg/L in citrate buffer. It also has good reproducibility with a relative standard deviation (%RSD) of 7.7%, and gives a stable response at time values greater than 5 min from exposure in a buffer solution, and the sensor can be utilized within five days from its synthesis. This optical pH sensor has been employed to determine saliva pH of people of different ages and showed no significant difference when compared to a potentiometric method.

scholarly journals Optical pH sensor based on polyelectrolyte complex (PEC) pectin-chitosan/methanol anthocyanin extract of Catharanthus roseus for a new optical urea biosensor development

2021 ◽  
Vol 21 (3) ◽  
pp. 135-141
Author(s):  
NURHAYATI NURHAYATI ◽  
EKA SAFITRI ◽  
KHAIRI SUHUD ◽  
NAZARUDDIN NAZARUDDIN ◽  
BINAWATI GINTING ◽  
...  
Keyword(s):  
Catharanthus Roseus ◽  
Phosphate Buffer ◽  
Polyelectrolyte Complex ◽  
Ph Sensor ◽  
Total Phenolic ◽  
Buffer Solution ◽  
Good Linearity ◽  
Relative Standard ◽  
Ph Range ◽  
Optical Ph Sensor

Construction of optical pH sensor as a new platform optical urea biosensor based on polyelectrolyte complex (PEC) pectin-chitosan membrane and total phenolic (anthocyanin) of Tapak Dara flower (Catharanthus roseus) has been successfully carried out. The anthocyanin was extracted by a maceration method for 72 hours using methanol, and a total extract yield was 21.56% or 1.803 mg/L. Flavonoid and phenol tests showed positive results indicated by the formation of red and black colours. The anthocyanins showed maximum absorption at 578 nm for phosphate buffer and 575 nm for tris HCl buffer solution. The sensor fabrication was performed using a mixture of pectin and chitosan solutions with a ratio of 3:7. The anthocyanin was mixed into the solution with various concentrations. The sensor has an optimum sensitivity at the anthocyanin concentration of 0.05 mg/L (phosphate buffer) in the pH range of 7.0-9.5 and 0.025 mg/L (Tris HCl buffer) with a narrower pH range of 6.0-7.5. This sensor produced higher sensitivity, a wider linear range, and good linearity when it was exposed in 0.03M PBS. Reproducibility test with a relative standard deviation percentage (% RSD) was 9.20. The sensor showed a stable response after 5 minutes exposed to PBS solution, and it can be used to measure pH within the 20th day. The optimized optical pH sensor has been successfully developed as a urea optical biosensor by immobilizing urease on its surface. The biosensor showed a linear response in a series of 10-1-10-10 M urea concentrations and has good linearity.

scholarly journals A simple optical pH sensor based on pectin and Ruellia tuberosa L-derived anthocyanin for fish freshness monitoring

F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 422
Author(s):  
Nazaruddin Nazaruddin ◽  
Nurul Afifah ◽  
Muhammad Bahi ◽  
Susilawati Susilawati ◽  
Nor Diyana Md. Sani ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Room Temperature ◽  
Ph Value ◽  
Ph Sensor ◽  
Phosphate Buffer Solution ◽  
Good Sensitivity ◽  
Buffer Solution ◽  
C Storage ◽  
Relative Standard ◽  
Optical Ph Sensor

A simple optical pH sensor using the active compound anthocyanin (ACN), derived Ruellia tuberosa L. flower immobilized in a pectin membrane matrix, was been fabricated and employed to monitor the freshness of tilapia fish at room temperature and 4oC storage. The optimum pectin weight and ACN concentrations were 0.1% and 0.025 mg/L. The sensor showed good sensitivity at 0.03 M phosphate buffer solution. The sensor’s reproducibility was evaluated using 10 replicate sensors where a standard deviation of 0.045 or relative standard deviation of 9.15 was achieved. The sensor displayed an excellent response after 10 minutes of exposure, possessing a response stability for 10 consecutive days. The decrease in pH value of the Tilapia fish from 7.3 to 5 was observed in a 48 hour test, which can be used as the parameter when monitoring fish freshness.

scholarly journals A simple optical pH sensor based on pectin and Ruellia tuberosa L-derived anthocyanin for fish freshness monitoring

F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 422
Author(s):  
Nazaruddin Nazaruddin ◽  
Nurul Afifah ◽  
Muhammad Bahi ◽  
Susilawati Susilawati ◽  
Nor Diyana Md. Sani ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Ph Value ◽  
Ph Sensor ◽  
Phosphate Buffer Solution ◽  
Buffer Solution ◽  
Rigor Mortis ◽  
C Storage ◽  
Relative Standard ◽  
Vis Spectroscopy ◽  
Optical Ph Sensor

A simple optical pH sensor using the active compound anthocyanin (ACN), derived Ruellia tuberosa L. flower immobilized in a pectin membrane matrix, was been fabricated and employed to monitor the freshness of tilapia fish at room temperature and 4oC storage. The quantitative pH values were measured based on the UV-Vis spectroscopy absorbance. The optimum pectin weight and ACN concentrations were 0.1% and 0.025 mg/L. The sensor showed good sensitivity at 0.03 M phosphate buffer solution. The sensor’s reproducibility was evaluated using 10 replicate sensors where a standard deviation of 0.045 or relative standard deviation of 9.15 was achieved. The sensor displayed an excellent response after 10 minutes of exposure, possessing a response stability for 10 consecutive days. The decrease in pH value of the Tilapia fish from 7.3 to 5 was observed in a 48 hour test, which can be used as the parameter when monitoring fish freshness. Overall, this reported optical pH sensor has a novelty as it could be used to monitor the rigor mortis phase of fish meat, which is useful in food industry.

scholarly journals Preparation and Characterization of a Pectin Membrane-Based Optical pH Sensor for Fish Freshness Monitoring

Biosensors ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 60 ◽  
Author(s):  
Uswatun Hasanah ◽  
Mita Setyowati ◽  
Rustam Efendi ◽  
Muslem Muslem ◽  
Nor Diyana Md Sani ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Response Time ◽  
Relative Standard Deviation ◽  
Ph Sensor ◽  
Sensor Response ◽  
Relative Standard ◽  
Optical Ph Sensor

In a simple and instant procedure for detecting fish freshness, a hydrogel and hydrophilic pectin matrix membrane was used successfully as an optical pH sensor by immobilizing the chromoionophore ETH 5294 (CI), which is very selective and sensitive for the membrane. The Pe/CI optical pH sensor exhibited excellent linearity between pH 5 and pH 9, with a sensor response time of 5 min and reproducibility of 1.49% relative standard deviation (RSD). The sensor showed response stability for 15 days and a response reduction of 8.6%. The sensor’s capability was demonstrated by the detection of fish freshness for 17 days at 4 °C.

scholarly journals Fabrication of an Immobilized Polyelectrolite Complex (PEC) Membrane from Pectin-Chitosan and Chromoionophore ETH 5294 for pH-Based Fish Freshness Monitoring

Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 88
Author(s):  
Eka Safitri ◽  
Zatul Omaira ◽  
Nazaruddin Nazaruddin ◽  
Irfan Mustafa ◽  
Sitti Saleha ◽  
...  
Keyword(s):  
Accurate Determination ◽  
Active Material ◽  
Ph Sensor ◽  
Wavelength Region ◽  
Trial And Error ◽  
Optimum Conditions ◽  
Relative Standard ◽  
Optimum Wavelength ◽  
Optical Ph Sensor

Considering the significance of its demand around the world, the accurate determination of fish freshness with a simple and rapid procedure has become an interesting issue for the fishing industry. Hence, we aimed to fabricate a new optical pH sensor based on a polyelectrolyte (PEC) membrane of pectin–chitosan and the active material chromoionophore ETH 5294. A trial-and-error investigation of the polymer compositions revealed that the optimum ratio of pectin to chitosan was 3:7. With an optimum wavelength region (λ) at 610 nm, the constructed sensor was capable of stable responses after 5 min exposure to phosphate-buffered solution. Furthermore, the obtained sensor achieved optimum sensitivity when the PBS concentration was 0.1 M, while the relative standard deviation values ranged from 2.07 to 2.34%, suggesting good reproducibility. Further investigation revealed that the sensor experienced decreased absorbance of 16.67–18.68% after 25 days of storage. Employing the optimum conditions stated previously, the sensor was tested to monitor fish freshness in samples that were stored at 4 °C and ambient temperature. The results suggested that the newly fabricated optical sensor could measure pH changes on fish skin after 25 h storage at room temperature (pH 6.37, 8.91 and 11.02, respectively) and 4 °C (pH 6.8, 7.31 and 7.92, respectively).

scholarly journals Development and characterization of cassava starch films incorporated with purple yam (Dioscorea alata L.) peel anthocyanins

Food Research ◽  
2020 ◽  
Vol 5 (1) ◽  
pp. 108-113
Author(s):  
A.M. Aquino ◽  
D.B. Morales
Keyword(s):  
Antioxidant Activity ◽  
Tensile Strength ◽  
Cassava Starch ◽  
Response Analysis ◽  
Dioscorea Alata ◽  
Anthocyanin Content ◽  
Ph Indicator ◽  
Significant Difference ◽  
Starch Films ◽  
Purple Yam

The packaging industry is now geared towards natural and biodegradable raw materials to reduce packaging wastes. In this study, purple yam (Dioscorea alata L.) peels were utilized to extract anthocyanins to be incorporated as a pH indicator in cassava starch films. The extract was analyzed for its total monomeric anthocyanin content (TMAC) using the pH differential method, and antioxidant activity using the DPPH assay. Results showed that the extract contains 155 mg/L cyanidin-3-glucoside and high antioxidant activity of 78.84%. Using the casting technique, thin films were made from cassava starch and glycerol, with varying amounts of the extract (0, 10, 20, 30 and 50%). The films were characterized by their color properties, water activity (Aw) and tensile strength (TS). Results showed decreasing values of L* , a* , b* as the concentration of the extract increased. No significant difference (p>0.05) was observed in the Aw and TS of the control film and the colored films. There was no trend observed in the Aw and TS of the films. The film with 30% extract recorded the lowest Aw (0.214) while the film with 40% extract recorded the highest tensile strength (0.706). The film with the highest TS was subjected to color response analysis by immersing the films in buffer solutions at different pH levels (pH 1.0-12.0) for 10 mins, and the time when the first color change was observed was recorded. The fastest responses were observed at the extreme pH levels (pH 1.0–2.0; 10.0–12.0). This study was able to conclude that purple yam peel extract has the potential as a pH indicator in cassava starch films for application as intelligent packaging.

A microfluidic device with integrated impedance detection for λ-DNA

2003 ◽  
Vol 773 ◽  
Author(s):  
Myung-Il Park ◽  
Jonging Hong ◽  
Dae Sung Yoon ◽  
Chong-Ook Park ◽  
Geunbae Im
Keyword(s):  
Microfluidic Device ◽  
Electrochemical Impedance ◽  
Direct Detection ◽  
Full Potential ◽  
Label Free ◽  
Buffer Solution ◽  
Detection Systems ◽  
Significant Difference ◽  
Detection Of Biomolecules ◽  
Impedance Magnitude

AbstractThe large optical detection systems that are typically utilized at present may not be able to reach their full potential as portable analysis tools. Accurate, early, and fast diagnosis for many diseases requires the direct detection of biomolecules such as DNA, proteins, and cells. In this research, a glass microchip with integrated microelectrodes has been fabricated, and the performance of electrochemical impedance detection was investigated for the biomolecules. We have used label-free λ-DNA as a sample biomolecule. By changing the distance between microelectrodes, the significant difference between DW and the TE buffer solution is obtained from the impedance-frequency measurements. In addition, the comparison for the impedance magnitude of DW, the TE buffer, and λ-DNA at the same distance was analyzed.

scholarly journals Optimization of an Ultrasound-Assisted Extraction Method for the Analysis of Major Anthocyanin Content in Erica australis Flowers

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2884
Author(s):  
Ceferino Carrera ◽  
María José Aliaño-González ◽  
Jaime Rodríguez-López ◽  
Marta Ferreiro-González ◽  
Fernando Ojeda-Copete ◽  
...  
Keyword(s):  
Folk Medicine ◽  
Anthocyanin Content ◽  
Extraction Temperature ◽  
Ultrasound Assisted Extraction ◽  
Assisted Extraction ◽  
Relative Standard ◽  
Precision Study ◽  
Ultrasound Assisted ◽  
Ph Level ◽  
Erica Australis

Erica australis plants have been used in infusions and folk medicine for years for its diuretic and antiseptic properties and even for the treatment of infections. In addition, a recently published thorough study on this species has demonstrated its antioxidant, antibiotic, anti-inflammatory, anticarcinogenic and even antitumoral activities. These properties have been associated with the high content of anthocyanins in E. australis leaves and flowers. The aim of the present research is to optimize an ultrasound-assisted extraction methodology for the recovery of the anthocyanins present in E. australis flowers. For that purpose, a Box Behnken design with response surface methodology was employed, and the influence of four variables at different values was determined: namely, the composition of the extraction solvents (0–50% MeOH in water), the pH level of those solvents (3–7), the extraction temperature (10–70 °C), and the sample:solvent ratio (0.5 g:10 mL–0.5 g:20 mL). UHPLC-UV-vis has been employed to quantify the two major anthocyanins detected in the samples. The extraction optimum conditions for 0.5 g samples were: 20 mL of solvent (50% MeOH:H2O) at 5 pH, with a 15 min extraction time at 70 °C. A precision study was performed and the intra-day and inter-day relative standard deviations (RSDs) obtained were 3.31% and 3.52%, respectively. The developed methodology has been successfully applied to other Erica species to validate the suitability of the method for anthocyanin extraction.

scholarly journals Antigen retrieval technique utilizing citrate buffer or urea solution for immunohistochemical demonstration of androgen receptor in formalin-fixed paraffin sections.

1993 ◽  
Vol 41 (11) ◽  
pp. 1599-1604 ◽  
Author(s):  
S R Shi ◽  
B Chaiwun ◽  
L Young ◽  
R J Cote ◽  
C R Taylor
Keyword(s):  
Androgen Receptor ◽  
Enzymatic Digestion ◽  
Antigen Retrieval ◽  
Urea Solution ◽  
Paraffin Sections ◽  
Buffer Solution ◽  
Solution Ph ◽  
Citrate Buffer ◽  
Formalin Fixed Paraffin ◽  
Formalin Fixed

We developed a staining protocol for demonstration of androgen receptor (AR) in formalin-fixed, paraffin-embedded tissue sections. The method is based on the antigen retrieval microwave (MW) heating technique. Results are compared with different types of enzyme digestion pre-treatments. The strongest immunostaining signal and clearest background were obtained by MW heating of dewaxed paraffin sections in 5% urea or citrate buffer solution (pH 6); pure distilled water gave less consistent results. Enzymatic digestion with pepsin (0.05% in 2 N HCl) for 30 min at room temperature, or trypsin followed by pronase, or pronase digestion alone, also produced enhanced staining of AR in some cases, but there was more nonspecific background, and specific reactivity was less intense. The antigen retrieval MW method can be used to demonstrate AR epitope in prostate tissue after fixation in formalin for as long as 7 days. AR immunolocalization was also compared in frozen and paraffin sections processed from the same specimen of prostate carcinoma tissue and was found to be qualitatively and quantitatively similar. This study also provided new information concerning the basic principles of the antigen retrieval MW method that may be helpful in further development of this technique.

An Optical pH Sensor Based on Diazocine

2017 ◽  
Vol 2 (26) ◽  
pp. 7956-7960 ◽  
Author(s):  
Yanan Liu ◽  
Zuwei Song ◽  
Libin Gao ◽  
Jianzhong Li
Keyword(s):  
Ph Sensor ◽  
Optical Ph Sensor
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