Development of exobiopolymer-based biosensor for detection of phosphate in water

2013 ◽  
Vol 68 (12) ◽  
pp. 2619-2625 ◽  
Author(s):  
Taranpreet Kaur ◽  
Abhijit Ganguli ◽  
Moushumi Ghosh

The present study was conducted to develop a biosensor by exploiting phosphate-binding capacity of exobiopolymer (EBP) produced by Acinetobacter sp. An environmental isolate of EBP-producing Acinetobacter sp. was subjected to transposon (Tn5) mutagenesis to overproduce EBP and afford improved phosphate selectivity. A mutant producing the highest amount of EBP with high phosphate-binding capacity was selected for biosensor probe fabrication. Phosphate samples were filtered through EBP-coated membranes and phosphate retained on membranes was determined by molybdenum blue method. The color produced was read using a LED 690 nm/photodiode detection system linked to an amplifier and signals were converted to appropriate phosphate concentrations. The biosensor had a limit of detection of 0.5 mg/L and a limit of quantification 1 mg/L. The biosensor as well as the probe were found to be stable for at least 28 days. In conclusion, we believe that the biosensor may have applications in monitoring of wastewater and environmental samples. Further, the enrichment of phosphate levels by EBP can help in analysis of very low phosphate concentrations.

2021 ◽  
Vol 11 ◽  
pp. 184798042098735
Author(s):  
Xiaohong Li ◽  
Wei Shi ◽  
Wenyan Zhang ◽  
Weiyao Chen ◽  
Dan Cao ◽  
...  

Parkinson’s disease (PD) is a nervous disorder, affects physical movement, and leads to difficulty in balancing, walking, and coordination. A novel sensor is mandatory to determine PD and monitor the progress of the treatment. Neurofilament light chain (NfL) has been recognized as a good biomarker for PD and also helps to distinguish between PD and atypical PD syndromes. Immunosensor was generated by current–volt measurement on gap-fingered interdigitated electrode with silicon dioxide surface to determine NfL level. To enhance the detection, anti-NfL antibody was complexed with gold-nanourchin and immobilized on the sensing electrode. The current–volt response was gradually increased at the linear detection range from 100 fM to 1 nM. Limit of detection and sensitivity were 100 fM with the signal-to-noise ratio at n = 3 on a linear curve ( y = 0.081 x + 1.593; R 2 = 0.9983). Limit of quantification falls at 1 pM and high performance of the sensor was demonstrated by discriminating against other neurogenerative disease markers, in addition, it was reproducible even in serum-spiked samples. This method of detection system aids to measure the level of NfL and leads to determine the condition with PD.


Author(s):  
Murat Soyseven ◽  
Rüstem Keçili ◽  
Hassan Y Aboul-Enein ◽  
Göksel Arli

Abstract A novel analytical method, based on high-performance liquid chromatography with a UV (HPLC-UV) detection system for the sensitive detection of a genotoxic impurity (GTI) 5-amino-2-chloropyridine (5A2Cl) in a model active pharmaceutical ingredient (API) tenoxicam (TNX), has been developed and validated. The HPLC-UV method was used for the determination of GTI 5A2Cl in API TNX. The compounds were separated using a mobile phase composed of water (pH 3 adjusted with orthophosphoric acid): MeOH, (50:50: v/v) on a C18 column (150 × 4.6 mm i.d., 2.7 μm) at a flow rate of 0.7 mL min−1. Detection was carried out in the 254 nm wavelength. Column temperature was maintained at 40°C during the analyses and 10 μL volume was injected into the HPLC-UV system. The method was validated in the range of 1–40 μg mL−1. The obtained calibration curves for the GTI compound was found linear with equation, y = 40766x − 1125,6 (R2 = 0.999). The developed analytical method toward the target compounds was accurate, and the achieved limit of detection and limit of quantification values for the target compound 5A2Cl were 0.015 and 0.048 μg mL−1, respectively. The recovery values were calculated and found to be between 98.80 and 100.03%. The developed RP-HPLC-UV analytical method in this research is accurate, precise, rapid, simple and appropriate for the sensitive analysis of target GTI 5A2Cl in model API TNX.


2014 ◽  
Vol 29 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Sanja Lazic ◽  
Dragana Sunjka ◽  
Srdjan Panic ◽  
Dusanka Indjic ◽  
Nada Grahovac ◽  
...  

Degradation of acetamiprid in sweet cherry samples was evaluated at several intervals from the product application until the end of the pre-harvest interval. An orchard of sweet cherries located at Stepanovicevo village near Novi Sad was used in this study. Acetamiprid was applied according to the manufacturer?s recommendation for protecting sweet cherries from their most important pests. Sweet cherry fruit samples were collected at eight intervals: immediately after acetamiprid application and 2, 4, 6, 8, 10, 12 and 14 days after application. The extraction of acetamiprid from sweet cherry samples was performed using a QuEChERS-based method. Determination was carried out using an HPLC-UV diode array detection system (Agilent 1100, United States) with an Agilent Zorbax Eclipse C18 column (50 mm C 4.6 mm internal diameter, 1.8 ?m particle size). The method was subjected to a thorough validation procedure. The recovery data were obtained by spiking blank sweet cherry samples at three concentration levels (0.1-0.3 mg/ kg), yielding 85.4% average recovery. Precision values expressed as relative standard deviation (RSD) were below 1.61% for the intraday precision. Acetamiprid showed linear calibrations from 0.05 to 2.5 ?g/ml with correlation coefficient (R2) of 0.995%. The limit of detection and limit of quantification were found to be 5 ?g/kg and 14 ?g/kg, respectively. The validated method was applied in the analysis of acetamiprid in sweet cherry samples. During the study period, the concentration of acetamiprid decreased from 0.529 mg/kg to 0.111 mg/kg. The content of acetamiprid in sweet cherry samples at the end of the pre-harvest interval was below the maximum permissible level specified by the Serbian and EU MRLs.


Author(s):  
Anna Gliszczyńska-Świgło ◽  
Iga Rybicka

AbstractThe spectrophotometric molybdenum blue method for phosphorus determination was adapted to a multiwell plate format. The method was sensitive and allowed for the simultaneous determination of phosphorus in many samples. It was cheap and eco-friendly due to application of small volumes of reagents and, therefore, it meets the requirements for “green” or sustainable chemistry. The method’s limit of detection (LOD) is 0.37 μg/mL and its limit of quantification (LOQ) is 1.13 μg/mL. Its linearity is up to 30 μg of phosphorus/mL. The method was applied for the determination of phosphorus in 65 dairy products (yogurts, yogurt drinks, buttermilks, kefirs and homogenized cheeses) of strawberry, peach, forest fruits, vanilla and other flavours. The phosphorus content was 143–226 mg/100 g in flavoured yogurts, 78–204 mg/100 g in yogurt drinks, 89–218 mg/100 g in kefirs, around 195 mg/100 g in buttermilks, and 165–277 mg/100 g in homogenized cheeses. The presented method can be used in the routine quantitative analysis of the total phosphorus content in dairy products.


Author(s):  
Mohammad Hamzah Hamzah ◽  
Rawa M M Taqi ◽  
Muna M. Hasan ◽  
Raid J. M. Al-Timimi

A simple and accurate spectrophotometric method for the determination of Trifluoperazine HCl in pure and dosage forms was developed. The method is based on the reaction between Trifluoperazine HCl and p-chloroaniline in the presence of cerium ion as oxidizing agent which lead to the formation of violate color product that absorbed at a maximum wavelength 570nm while the blank solution was pink. Under the optimum conditions a linear relationship between the intensity and concentration of TRF in the range 4-50μg/ml was obtained . The molar absorptivity 3.74×103 L.mol-1.cm-1 , Limit of detection (2.21μg/ml), while limit of quantification was 7.39μg/ml. The proposed analytical method was compared with standard method using t-test and F-test , the obtained results shows there is no significant differences between proposed method and standard method. Based on that the proposed method can be used as an alternative method for the determination of TRF in pure and dosage forms.


Author(s):  
Sidra Amin ◽  
Amber R. Solangi ◽  
Dilawar Hassan ◽  
Nadir Hussain ◽  
Jamil Ahmed ◽  
...  

Background: In recent years, the occurrence and fate of environmental pollutants has been recognized as one of the emerging issues in environmental chemistry. A survey documented about a wide variety of these pollutants, which are often detected in our environment and these are major cause of shortened life spans and the global warming. These pollutants include toxic metal, pesticides, fertilizers, drugs and dyes released into soil and major water bodies. The presence of these contaminants causes major disturbance in eco-system’s balance. To tackle these issues many technological improvements are made to detect minute contaminations. The latest issue being answered by the scientists is the use of green nano materials as sensors which are economical, instant and give much better results at low concentrations and can be used for the field measurements resulting in no dangerous by-product that could lead to more environmental contamination. Nano materials are known for their wide band gap, enhanced physical and optical properties with option of tuneablity as per need, by optimizing certain parameters. They are proved to be good choice for analytical/optical sensors with high sensitivity. Objective: This review holds information about multiple methods that use green nanomaterials for the analytical assessment of environmental pollutants. UV-Vis spectrophotometry and electrochemical analysis using green and reproducible nanomaterials are the major focus of this review article. To date, there are number of spectrophotometric and electro chemical methods available that have been used for the detection of environmental pollutants such as toxic metals, pesticides and dyes. Conclusion: The use of nanomaterials can drastically change the detection limits due to having large surface area, strong catalytic properties, and tunable possibility. With the use of nano materials, lower than the marked limit of detection and limit of quantification were seen when compared with previously reported work. The used nano-materials could be washed, dried, and reused, which makes the methods more proficient, cost effective and environmentally friendly.


2020 ◽  
Vol 16 ◽  
Author(s):  
Nadereh Rahbar ◽  
Fatemeh Ahmadi ◽  
Zahra Ramezani ◽  
Masoumeh Nourani

Background: Sample preparation is one of the most challenging phases in pharmaceutical analysis, especially in biological matrices, affecting the whole analytical methodology. Objective: In this study, a new Ca(II)/Cu(II)/alginate/CuO nanoparticles hydrogel fiber (CCACHF) was synthesized through a simple, green procedure and applied for fiber micro solid phase extraction (FMSPE) of diazepam (DIZ) and oxazepam (OXZ) as model drugs prior to high-performance liquid chromatography-UV detection (HPLC-UV). Methods: Composition and morphology of the prepared fiber were characterized and the effect of main parameters on the fiber fabrication and extraction efficiency have been studied and optimized. Results: In optimal conditions, calibration curves were linear ranging between 0.1–500 µg L−1 with regression coefficients of 0.9938 and 0.9968. Limit of detection (LOD) (S/N=3) and limit of quantification (LOQ) (S/N=10) of the technique for DIZ and OXZ were 0.03 to 0.1 µg L−1. Within-day and between-day relative standard deviations (RSDs) for DIZ and OXZ were 6.0–12.5% and 3.3–9.4%, respectively. Conclusion: The fabricated adsorbent has been substantially employed to extraction of selected benzo-diazepines (BZDs) from human serum real specimens and the obtained recoveries were also satisfactory (82.1-109.7%).


2020 ◽  
Vol 16 (3) ◽  
pp. 277-286
Author(s):  
Amal A. El-Masry ◽  
Mohammed E. A. Hammouda ◽  
Dalia R. El-Wasseef ◽  
Saadia M. El-Ashry

Background: The first highly sensitive, rapid and specific green microemulsion liquid chromatographic (MELC) method was established for the simultaneous estimation of fluticasone propionate (FLU) and azelastine HCl (AZL) in the presence of their pharmaceutical dosage form additives (phenylethyl alcohol (PEA) and benzalkonium chloride (BNZ)). Methods: The separation was performed on a C18 column using (o/w) microemulsion as a mobile phase which contains 0.2 M sodium dodecyl sulphate (SDS) as surfactant, 10% butanol as cosurfactant, 1% n-octanol as internal phase and 0.3% triethylamine (TEA) adjusted at pH 6 by 0.02 M phosphoric acid; with UV detection at 220 nm and programmed with flow rate of 1 mL/min. Results: The validation characteristics e.g. linearity, lower limit of quantification (LOQ), lower limit of detection (LOD), accuracy, precision, robustness and specificity were investigated. The proposed method showed linearity over the concentration range of (0.5-25 µg/mL) and (0.1-25 µg/mL) for FLU and AZL, respectively. Besides that, the method was adopted in a short chromatographic run with satisfactory resolution factors of (2.39, 3.78 and 6.74 between PEA/FLU, FLU/AZL and AZL/BNZ), respectively. The performed method was efficiently applied to pharmaceutical nasal spray with (mean recoveries ± SD) (99.80 ± 0.97) and (100.26 ± 0.96) for FLU and AZL, respectively. Conclusion: The suggested method was based on simultaneous determination of FLU and AZL in the presence of PEA and BNZ in pure form, laboratory synthetic mixture and its combined pharmaceutical dosage form using green MELC technique with UV detection. The proposed method appeared to be superior to the reported ones of being more sensitive and specific, as well as the separation was achieved with good performance in a relatively short analysis time (less than 7.5 min). Highly acceptable values of LOD and % RSD make this method superior to be used in quality control laboratories with of HPLC technique.


2021 ◽  
Vol 9 (5) ◽  
pp. 1031
Author(s):  
Roberto Zoccola ◽  
Alessia Di Blasio ◽  
Tiziana Bossotto ◽  
Angela Pontei ◽  
Maria Angelillo ◽  
...  

Mycobacterium chimaera is an emerging pathogen associated with endocarditis and vasculitis following cardiac surgery. Although it can take up to 6–8 weeks to culture on selective solid media, culture-based detection remains the gold standard for diagnosis, so more rapid methods are urgently needed. For the present study, we processed environmental M. chimaera infected simulates at volumes defined in international guidelines. Each preparation underwent real-time PCR; inoculates were placed in a VersaTREK™ automated microbial detection system and onto selective Middlebrook 7H11 agar plates. The validation tests showed that real-time PCR detected DNA up to a concentration of 10 ng/µL. A comparison of the isolation tests showed that the PCR method detected DNA in a dilution of ×102 CFU/mL in the bacterial suspensions, whereas the limit of detection in the VersaTREK™ was <10 CFU/mL. Within less than 3 days, the VersaTREK™ detected an initial bacterial load of 100 CFU. The detection limit did not seem to be influenced by NaOH decontamination or the initial water sample volume; analytical sensitivity was 1.5 × 102 CFU/mL; positivity was determined in under 15 days. VersaTREK™ can expedite mycobacterial growth in a culture. When combined with PCR, it can increase the overall recovery of mycobacteria in environmental samples, making it potentially applicable for microbial control in the hospital setting and also in environments with low levels of contamination by viable mycobacteria.


Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2797
Author(s):  
Jing-Jhong Gao ◽  
Ching-Wei Chiu ◽  
Kuo-Hsing Wen ◽  
Cheng-Sheng Huang

This paper presents a compact spectral detection system for common fluorescent and colorimetric assays. This system includes a gradient grating period guided-mode resonance (GGP-GMR) filter and charge-coupled device. In its current form, the GGP-GMR filter, which has a size of less than 2.5 mm, can achieve a spectral detection range of 500–700 nm. Through the direct measurement of the fluorescence emission, the proposed system was demonstrated to detect both the peak wavelength and its corresponding intensity. One fluorescent assay (albumin) and two colorimetric assays (albumin and creatinine) were performed to demonstrate the practical application of the proposed system for quantifying common liquid assays. The results of our system exhibited suitable agreement with those of a commercial spectrometer in terms of the assay sensitivity and limit of detection (LOD). With the proposed system, the fluorescent albumin, colorimetric albumin, and colorimetric creatinine assays achieved LODs of 40.99 and 398 and 25.49 mg/L, respectively. For a wide selection of biomolecules in point-of-care applications, the spectral detection range achieved by the GGP-GMR filter can be further extended and the simple and compact optical path configuration can be integrated with a lab-on-a-chip system.


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