scholarly journals A Novel Bismuth-Chitosan Nanocomposite Sensor for Simultaneous Detection of Pb(II), Cd(II) and Zn(II) in Wastewater

Micromachines ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 511 ◽  
Author(s):  
Hwang ◽  
Pathak ◽  
Wang ◽  
Rodriguez ◽  
Cho ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Detection Limit ◽  
Simultaneous Detection ◽  
Soil Leachate ◽  
Limit Values ◽  
Relative Standard ◽  
Real Wastewater ◽  
Stock Solutions ◽  
Multiple Heavy Metals ◽  
Nanocomposite Sensor

A novel bismuth (Bi)-biopolymer (chitosan) nanocomposite screen-printed carbon electrode was developed using a Bi and chitosan co-electrodepositing technique for detecting multiple heavy metal ions. The developed sensor was fabricated with environmentally benign materials and processes. In real wastewater, heavy metal detection was evaluated by the developed sensor using square wave anodic stripping voltammetry (SWASV). The nanocomposite sensor showed the detection limit of 0.1 ppb Zn2+, 0.1 ppb Cd2+ and 0.2 ppb Pb2+ in stock solutions. The improved sensitivity of the Bi-chitosan nanocomposite sensor over previously reported Bi nanocomposite sensors was attributed to the role of chitosan. When used for real wastewater samples collected from a mining site and soil leachate, similar detection limit values with 0.4 ppb Cd2+ and 0.3 ppb Pb2+ were obtained with relative standard deviations (RSD) ranging from 1.3% to 5.6% (n = 8). Temperature changes (4 and 23 °C) showed no significant impact on sensor performance. Although Zn2+ in stock solutions was well measured by the sensor, the interference observed while detecting Zn2+ in the presence of Cu2+ was possibly due to the presence of Cu-Zn intermetallic species in mining wastewater. Overall, the developed sensor has the capability of monitoring multiple heavy metals in contaminated water samples without the need for complicated sample preparation or transportation of samples to a laboratory.

scholarly journals SCHEMES OF SOLID-PHASE SPECTROPHOTOMETRIC ANALYSIS OF FOOD OBJECTS

2018 ◽  
Vol 3 ◽  
pp. 33-40
Author(s):  
Elizaveta Kostenko ◽  
Elena Butenko ◽  
Larisa Arseneva
Keyword(s):  
Detection Limit ◽  
Metal Ions ◽  
Solid Phase ◽  
Food Products ◽  
Ion Exchangers ◽  
Standard Samples ◽  
Limit Values ◽  
Standard Methods ◽  
Relative Standard

The aim of research is development of approaches to the development of schemes for microelement analysis of food objects. This will make it possible to monitor food quality by simple and affordable methods in factory laboratories. Based on data on the immobilization of dyes on ion exchangers and on the interaction of metal ions or their complexes with immobilized dyes, solid-phase spectrophotometric (SPS) and photometric methods for determining metal ions in food technology, biotechnology and the environment have been developed. Techniques are sensitive. High distribution coefficients (D³104 cm3/g) of metal ions help to reduce the detection limit when using immobilized dye as compared to the reaction in solution. Based on the detection limit values (DLV), the proposed sorption-spectrophotometric methods for determining metal ions are second only to the atomic absorption (AAS) determination of Cd (II) and Hg (II) ions and the polarographic determination of Cd (II) ions. However, the proposed methods for the determination of these metal ions are sufficient for the determination of Cd (II) and Hg (II) ions in food products at the MPC level. In the case of determination of Pb (II), Zn (II), Cu (II), Fe (III) ions, the developed methods have advantages over standard methods for determination of metal ions in food products, since they make it possible to determine these ions at a level ≤0.1…0.5 MPC; Ion exchangers with immobilized dyes and solid-phase spectrophotometric determination methods with their participation are environmentally safe, since they do not require the use of toxic organic reagents; are simple in execution and economically advantageous because of the low cost of used materials and reagents. The correctness of the results of the determination by the developed methods is proved: by comparison with the results of determinations on standard methods at various analysis objects using the method of additives, standard samples. The relative standard deviation of the developed SPS determination procedures does not exceed 0.10, which indicates satisfactory reproducibility of the results. The developed methods exceed the majority of standard and best analogs, known from the literature, for sensitivity and selectivity. The used methods of analysis are characterized by the simplicity of the experiment, ecological safety, do not require special expensive equipment, highly qualified personnel and a stationary laboratory.

scholarly journals Development and application of a triplex real-time PCR assay for simultaneous detection of avian influenza virus, Newcastle disease virus, and duck Tembusu virus

2020 ◽  
Author(s):  
Xiyu Zhang ◽  
Ming Yao ◽  
Zhihui Tang ◽  
Daning Xu ◽  
Yan Luo ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Standard Deviation ◽  
Detection Limit ◽  
Avian Influenza ◽  
Real Time ◽  
Newcastle Disease ◽  
Simultaneous Detection ◽  
Pcr Assay ◽  
Duck Tembusu Virus ◽  
Relative Standard

Abstract Background：At present, pathogens including duck-origin avian influenza virus (AIV), duck-origin Newcastle disease virus (NDV) and duck Tembusu virus (DTMUV) have posed great harm to ducks and caused great economic losses to the duck industry. Therefore, these viruses should be detected as early as possible in suspected duck flocks. This study aims to develop and apply a triplex real-time polymerase chain reaction (PCR) assay that can simultaneously detect these three viruses. Results：A sensitivity test shows that the positive detection limit of real-time PCR was at least 10 times higher than that of conventional PCR, with a detection limit of 1×101 copies/μL for AIV, NDV, and DTMUV. Furthermore, the cross-reactivity study of this method with other avian respiratory viruses suggested that the triplex assay was highly specific. The intra-day relative standard deviation and inter-day relative standard deviation were lower than 4.88% for these viruses at three different concentrations. Eventually, a total of 120 clinical samples were evaluated by the developed assay as well as routine PCR. Results showed that the positive rates for these two methods were 23.3% and 17.5%. Conclusion：The method developed in this research is rapid, specific and sensitive. It is feasible and effective for simultaneous detection of AIV, NDV, and DTMUV in ducks.

The fluorimetric determination of cerium and terbium

1989 ◽  
Vol 54 (3) ◽  
pp. 616-621 ◽  
Author(s):  
Záviš Holzbecher
Keyword(s):  
Rare Earth ◽  
Detection Limit ◽  
Rare Earth Elements ◽  
Fluorimetric Determination ◽  
Fluorescence Maximum ◽  
Relative Standard ◽  
And Shifts ◽  
Hcl Medium ◽  
Fold Excess

It has been found that phosphoric acid decreases the first excitation maximum of Ce(III) at 256 nm, increases the second excitation maximum at 297 nm and shifts the fluorescence maximum from 350 to 346 nm. Under optimum conditions, with λexc = 297 nm and λem = 346 nm, Ce(III) can be determined fluorimetrically with a detection limit of 1.2 ng ml-1 in 12M-H3PO4 medium. No interference was observed from a 20-200 fold excess of HCl, H2SO4, Na, K, NH4+, Al and the rare earth elements. HNO3 interferes and Ce(IV) and Fe(III) interfere strongly. It follows from the stereofluorograms of Ce and Tb that the spectra of the two elements are practically independent. The detection limit for Tb(III) in 0.02-2.5M-H2SO4 medium for λexc = 222 nm and λem = 494 nm is 33 ng ml-1. No interference was observed from a 5-20 fold excess of Al3+ and the other rare earth elements. The determination is slightly less sensitive in H3PO4 or HCl medium. The relative standard deviation of the measurement for 10 ng ml-1 Ce(III) or 50 ng ml-1 Tb(III) is about 3%.

scholarly journals Novel nanoscale Yb-MOF used as highly efficient electrode for simultaneous detection of heavy metal ions

2021 ◽  
Vol 56 (13) ◽  
pp. 8172-8185
Author(s):  
Manh B. Nguyen ◽  
Dau Thi Ngoc Nga ◽  
Vu Thi Thu ◽  
Benoît Piro ◽  
Thuan Nguyen Pham Truong ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Simultaneous Detection ◽  
Highly Efficient

Heavy metal and essential elements in beers from turkey market: A risk assessment study

2021 ◽  
pp. 096032712199321
Author(s):  
M Charehsaz ◽  
S Helvacıoğlu ◽  
S Çetinkaya ◽  
R Demir ◽  
O Erdem ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Inductively Coupled Plasma ◽  
Hazard Quotient ◽  
Daily Intake ◽  
Hazard Index ◽  
Carcinogenic Risk ◽  
Essential Elements ◽  
Inductively Coupled ◽  
Multiple Heavy Metals

In this study, the level of arsenic (As), lead (Pb) and cadmium (Cd) and also essential elements in beer samples consumed in Turkey were investigated using the inductively coupled plasma mass spectrometry (ICP-MS) method. The heavy metal-induced non-carcinogenic and carcinogenic risks were calculated. For essential elements, the calculated estimated daily intake of iron (Fe), copper (Cu), selenium (Se) and cobalt (Co) from beer consumption were compared with their toxicity reference values. Tukey post-hoc test showed that As was found at a significantly higher level when compared to Pb. Also, a significant correlation was found between As level and alcohol by volume percent. All samples had a hazard quotient and hazard index <1, indicating no non-carcinogenic risk from exposure to single or multiple heavy metals. Some samples exceeded the threshold limit of acceptable cancer risk for As in the high beer consumer group. This assessment showed that in addition to health implications based on the alcohol content of beer, there might be a carcinogenic risk associated with the heavy metals content of these beverages.

scholarly journals Simultaneous Rapid Detection of Aflatoxin B1 and Ochratoxin A in Spices Using Lateral Flow Immuno-Chromatographic Assay

Foods ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2738
Author(s):  
Xue Zhao ◽  
Xindi Jin ◽  
Zhang Lin ◽  
Qi Guo ◽  
Bin Liu ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Aflatoxin B1 ◽  
High Performance ◽  
Simultaneous Detection ◽  
High Sensitivity ◽  
Strong Stability ◽  
Test Strip ◽  
Chromatography Analysis ◽  
Relative Standard ◽  
Strip Test

Spices are susceptible to contamination by aflatoxin B1 (AFB1) and ochratoxin A (OTA), which are both mycotoxins with high toxicity and carcinogenicity. In this study, we aimed to develop an immuno-chromatographic strip test for the simultaneous quantification of AFB1 and OTA in spices by spraying the coupled antigens AFB1–ovalbumin (AFB1–OVA) and OTA–ovalbumin (OTA–OVA) on a nitrocellulose membrane. The test strip had high sensitivity, good specificity, and strong stability. The detection limits of these two mycotoxins in Chinese prickly ash, pepper, chili, cinnamon, and aniseed were 5 μg/kg. The false positivity rate was 2%, and the false negativity rate was 0%. The maximum coefficient of variation was 4.28% between batches and 5.72% within batches. The average recovery rates of AFB1 and OTA in spices were 81.2–113.7% and 82.2–118.6%, respectively, and the relative standard deviation (RSD) was <10%. The actual sample detection was consistent with high performance liquid chromatography analysis results. Therefore, the immuno-chromatographic test strips developed in this study can be used for the on-site simultaneous detection of AFB1 and OTA in spices. This method would allow the relevant regulatory agencies to strengthen supervision in an effort to reduce the possible human health hazards of such contaminated spices.

scholarly journals Spectrophotometric flow injection procedure to indirect determination of paracetamol in pharmaceutical formulations using o-tolidine as reagent

2018 ◽  
Vol 33 (2) ◽  
pp. 47
Author(s):  
Orlando Fatibello-Filho ◽  
Heberth Juliano Vieira
Keyword(s):  
Standard Deviation ◽  
Detection Limit ◽  
Flow Injection ◽  
Pharmaceutical Formulations ◽  
Injection Method ◽  
Indirect Determination ◽  
Analytical Curve ◽  
Relative Standard ◽  
Injection Procedure

A spectrophotometric flow injection method for the determination of paracetamol in pharmaceutical formulations is proposed. The procedure was based on the oxidation of paracetamol by sodium hypochloride and the determination of the excess of this oxidant using o-tolidine dichloride as chromogenic reagent at 430 nm. The analytical curve was linear in the paracetamol concentration range from 8.50 x 10-6 to 2.51 x 10-4 mol L-1 with a detection limit of 5.0 x 10-6 mol L-1. The relative standard deviation was smaller than 1.2% for 1.20 x 10-4 mol L-1 paracetamol solution (n = 10). The results obtained for paracetamol in pharmaceutical formulations using the proposed flow injection method and those obtained using a USP Pharmacopoeia method are in agreement at the 95% confidence level.

scholarly journals Arsenic and heavy metal concentrations in agricultural soils in South Savo province

2002 ◽  
Vol 11 (4) ◽  
pp. 285-300 ◽  
Author(s):  
V. MÄNTYLAHTI ◽  
P. LAAKSO
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Agricultural Soils ◽  
Mineral Soil ◽  
Soil Samples ◽  
Potential Hazard ◽  
Metal Concentrations ◽  
Limit Values ◽  
Heavy Metal Concentrations ◽  
Target Values

Increasing concentrations of arsenic and heavy metals in agricultural soils are becoming a growing problem in industrialized countries. These harmful elements represent the basis of a range of problems in the food chain, and are a potential hazard for animal and human health. It is therefore important to gauge their absolute and relative concentrations in soils that are used for crop production. In this study the arsenic and heavy metal concentrations in 274 mineral soil samples and 38 organogenic soil samples taken from South Savo province in 2000 were determined using the aqua regia extraction technique. The soil samples were collected from 23 farms.The elements analyzed were arsenic, cadmium, chromium, copper, mercury, nickel, lead and zinc. The median concentrations in the mineral soils were:As 2.90 mg kg –1, Cd 0.084 mg kg –1, Cr 17.0 mg kg –1, Cu 13.0 mg kg –1, Hg 0.060 mg kg –1, Ni 5.4 mg kg –1, Pb 7.7 mg kg –1, Zn 36.5 mg kg –1. The corresponding values in the organogenic soils were:As 2.80 mg kg –1, Cd 0.265 mg kg –1, Cr 15.0 mg kg –1, Cu 29.0 mg kg –1, Hg 0.200 mg kg –1, Ni 5.9 mg kg –1, Pb 11.0 mg kg –1, Zn 25.5 mg kg –1. The results indicated that cadmium and mercury concentrations in the mineral and organogenic soils differed. Some of the arsenic, cadmium and mercury concentrations exceeded the normative values but did not exceed limit values. Most of the agricultural fields in South Savo province contained only small amounts of arsenic and heavy metals and could be classified as “Clean Soil”. A draft for the target values of arsenic and heavy metal concentrations in “Clean Soil” is presented.;

Simultaneous Enrichment and On-line Detection of Low-Concentration Copper, Cobalt, and Nickel Ions in Water by Near-Infrared Diffuse Reflectance Spectroscopy Combined with Chemometrics

2017 ◽  
Vol 100 (2) ◽  
pp. 560-565 ◽  
Author(s):  
Jibran Iqbal ◽  
Yiping Du ◽  
Fares Howari ◽  
Mahmoud Bataineh ◽  
Nawshad Muhammad ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Fluidized Bed ◽  
Relative Error ◽  
Heavy Metal Ions ◽  
Diffuse Reflectance ◽  
Diffuse Reflectance Spectroscopy ◽  
Simultaneous Detection ◽  
Quantitative Detection ◽  
On Line

Abstract Sensitive detection of heavy metal ions in water is of great importance considering the effects that heavy metals have on public health. A developed fluidized bed enrichment technique was used to concentrate and detect low concentrations of Cu2+, Co2+, and Ni2+ in water samples by near-IR diffuse reflectance (NIDR) spectroscopy (NIDRS) directly without using any chemicals or reagents. The NIDR spectraof adsorbent were measured on-line, and quantitative detection was achieved by applying a built partial least-squares chemometric model. Sensitivity and accuracy was improved significantly because large-volume mixture solutions were used in the enrichment process. Root mean square error of cross-validation values for Cu2+, Co2+, and Ni2+ were 0.29, 0.41, and 0.35 μg/mL, respectively, with mean relative error values in the acceptable range of 6.56–10.27%. This study confirms the potential application of fluidized bed enrichment combined with NIDRS and chemometrics for the simultaneous detection of trace heavy metal ions in water, with low relative error.

Synthesis of CuxNi(1−x)O coral-like nanostructures and their application in the design of a reusable toxic heavy metal ion sensor based on an adsorption-mediated electrochemical technique

2017 ◽  
Vol 4 (1) ◽  
pp. 191-202 ◽  
Author(s):  
Sayan Dey ◽  
Sumita Santra ◽  
Anupam Midya ◽  
Prasanta Kumar Guha ◽  
Samit Kumar Ray
Keyword(s):  
Heavy Metal ◽  
Detection Limit ◽  
Metal Ion ◽  
High Selectivity ◽  
Heavy Metal Ion ◽  
Electrochemical Technique ◽  
Toxic Heavy Metal ◽  
Ion Sensors ◽  
Metal Ion Sensors ◽  
Very High

Nanostructured, Cu-doped nickel oxides serve as excellent, ultra-fast, re-usable heavy metal ion sensors with an ultra-low detection limit and very high selectivity towards toxic Cr(vi) ions.

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