scholarly journals A Simple Distance Paper-Based Analytical Device for the Screening of Lead in Food Matrices

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 90
Author(s):  
Kasinee Katelakha ◽  
Vanida Nopponpunth ◽  
Watcharee Boonlue ◽  
Wanida Laiwattanapaisal
Keyword(s):  
Limit Of Detection ◽  
Field Measurements ◽  
Standard Addition ◽  
Lower Amount ◽  
Carminic Acid ◽  
Red Color ◽  
Calcium Magnesium ◽  
Standard Additions ◽  
Food Matrices ◽  
Analytical Device

A simple and rapid distance paper-based analytical device (dPAD) for the detection of lead (Pb) in foods is proposed herein. The assay principle is based on competitive binding between carminic acid (CA) and polyethyleneimine (PEI) to Pb in a food sample. The paper channels were pre-immobilized with PEI, before reacting with a mixture of the sample and CA. Pb can strongly bind to the CA; hence, the length of the red color deposition on the flow channel decreased as a lower amount of free CA bound to PEI. The dPAD exhibited good linear correlation, with ranges of 5–100 µg·mL−1 (R2 = 0.974) of Pb. Although, the limit of detection (LOD) of this platform was rather high, at 12.3 µg·mL−1, a series of standard additions (8.0, 9.0, and 10.0 µg·mL−1) can be used to interpret the cutoff of Pb concentrations at higher or lower than 2 µg·mL−1. The presence of common metal ions such as calcium, magnesium, nickel, and zinc did not interfere with the color distance readout. The validity of the developed dPAD was demonstrated by its applicability to screen the contamination of Pb in century egg samples. The results obtained from the dPAD are in accordance with the concentration measured by atomic absorption spectroscopy (AAS) (n = 9). In conclusion, this proposed dPAD, combined with the standard addition method, could be applied for screening Pb contamination in food matrices. This platform is, therefore, potentially applicable for field measurements of Pb in developing countries, because it is cheap and rapid, and it requires no significant laborious instruments.

Determination of aluminum, barium, molybdenum, scandium, berylium, titanium, vanadium, fluoride and boron in highly salinated waters

1996 ◽  
Vol 33 (6) ◽  
pp. 349-356 ◽  
Author(s):  
Malgorzata Bebek ◽  
Krzysztof Mitko ◽  
Jerzy Kwapulinsk
Keyword(s):  
Water Pollution ◽  
Trace Metals ◽  
Ion Exchange ◽  
Limit Of Detection ◽  
Standard Addition ◽  
Carminic Acid ◽  
Colour Reaction ◽  
Organic Extraction ◽  
Titanium Vanadium

Boron was determined in strongly salinated waters by ion exchange with selective ion exchanger AMBERLITE IRA 743 using a bath technique. Modified colour reaction with carminic acid was used to the final determination in 3 cm cuvettes at 615 nm. Limit of detection was 0.02 mgB/dm3 and no interference was observed during ion exchange in natural strong salinated samples. Determination of trace metals was carried out by flame AAS with N2O as oxidizing gas. Elaborated method allows to analyze water samples of each value of salinity. In the case of samples with TDS of more than dm3 it is necessary to dilute samples prior to analysis and with TDS in range from 10 to 20 g/dm3 standard addition is applicable as a rule and limit of detection is about 2 to 3 times worse than in non salinated samples. Presented method is very usable in place of uncomfortable, time-consuming and environment contaminating methods with organic extraction and it still allows to determine concentration at levels required in water pollution normatives. Colour reaction with SPANDS and zirconyl ions was used for determination of fluoride in the concentration range from 0.02 to 2 mgF−/dm3. Measurement of absorbance was carried out at 570 nm using 2 cm cuvettes. In the case of middle or highly salinated waters it is essential to preliminarily dilute sample and use the method of standard addition.

scholarly journals Spectrophotometric Determination of Zidovudine in Pharmaceuticals Based on Charge-Transfer Complexation Involving N-Bromosuccinimide, Metol and Sulphanilic Acid as Reagents

2007 ◽  
Vol 4 (2) ◽  
pp. 173-179 ◽  
Author(s):  
K. Basavaiah ◽  
U. R. Anil Kumar
Keyword(s):  
Limit Of Detection ◽  
Pharmaceutical Preparations ◽  
Reference Method ◽  
Standard Addition ◽  
Molar Absorptivity ◽  
Sulphanilic Acid ◽  
Bulk Drug ◽  
Student’S T ◽  
Charge Transfer Complexation

A simple spectrophotometric method is proposed for the determination of zidovudine(ZDV) in bulk drug and in pharmaceutical preparations. The method is based on the oxidation of ZDV by a known excess of oxidant N-bromosuccinimide (NBS), in buffer medium of pH 1.5, followed by the estimation of unreacted amount of oxidant with metol and sulphanilic acid. The reacted oxidant corresponds to the amount ZDV. The purple-red reaction product absorbs maximally at 530 nm and Beer’s law is obeyed over a range 5 to 75 μg mL-1. The apparent molar absorptivity is calculated to be 5.1×103L mol-1cm-1, and the corresponding Sandell sensitivity value is 0.052 μg cm-2. The limit of detection and quantification are found to be 0.90 and 2.72, respectively. Intra-day and inter-day precision and accuracy of the developed methods were evaluated as per the current ICH guidelines. The method was successfully applied to the assay of ZDV in tablet/capsule preparations and the results were statistically compared with those of the reference method by applying the Student’s t-test and F-test. No interference was observed from the common tablet/capsule excipients. The accuracy of the method was further ascertained by performing recovery studies via standard-addition method.

scholarly journals Cerimetric determination of simvastatin in pharmaceuticals based on redox and complex formation reactions

2018 ◽  
Vol 33 (2) ◽  
pp. 21
Author(s):  
Kanakapura Basavaiah ◽  
Okram Zenita Devi
Keyword(s):  
Limit Of Detection ◽  
Reference Method ◽  
Standard Addition ◽  
Molar Absorptivity ◽  
Experimental Conditions ◽  
Spectrophotometric Methods ◽  
Fixed Quantity ◽  
Bulk Drug ◽  
Student’S T

Two sensitive spectrophotometric methods are described for the determination of simvastatin (SMT) in bulk drug and in tablets. The methods are based on the oxidation of SMT by a measured excess of cerium (IV) in acid medium followed by determination of unreacted oxidant by two different reaction schemes. In one procedure (method A), the residual cerium (IV) is reacted with a fixed concentration of ferroin and the increase in absorbance is measured at 510 nm. The second approach (method B) involves thereduction of the unreacted cerium (IV) with a fixed quantity of iron (II), and the resulting iron (III) is complexed with thiocyanate and the absorbance measured at 470 nm. In both methods, the amount of cerium (IV) reacted corresponds to SMT concentration. The experimental conditions for both methods were optimized. In method A, the absorbance is found to increase linearly with SMT concentration (r = 0.9995) whereas in method B, the same decreased (r = -0.9943). The systems obey Beer’s law for 0.6-7.5 and 0.5-5.0 μg mL-1 for method A and method B, respectively. The calculated molar absorptivity values are 2.7 X 104 and 1.06 X 105 Lmol-1 cm-1, respectively; and the corresponding sandel sensitivity values are 0.0153 and 0.0039μg cm-2, respectively. The limit of detection (LOD) and quantification (LOQ) are reported for both methods. Intra-day and inter-day precision, and accuracy of the methods were established as per the current ICH guidelines. The methods were successfully applied to the determination of SMT in tablets and the results were statistically compared with those of the reference method by applying the Student’s t-test and F-test. No interference was observed from the common excipients added to tablets. The accuracy and validity of the methods were further ascertained by performing recovery experiments via standard addition procedure.

scholarly journals ELIMINASI GANGGUAN MATRIKS DALAM ANALISIS MERKURI HG SEBAGAI SENYAWA KOMPLEKS THIO MICHLER’S KETON SECARA SPEKTROFOTOMETRI

2016 ◽  
Vol 11 (1) ◽  
Author(s):  
Sukib Sukib ◽  
Muti'ah Muti'ah
Keyword(s):  
Solvent Extraction ◽  
River Water ◽  
Complex Compound ◽  
Limit Of Detection ◽  
Standard Addition ◽  
Analysis Method ◽  
Addition Method ◽  
Matrix Interferences ◽  
Mercury Analysis

Abstrak. Telah dilakukan penelitian tentang penyusunan metode analisis merkuri melalui pembentukan senyawa kompleks dengan 4,4'-Bis(dimethylamino)thio-benzophenone TMK. Senyawa kompleks tersebut berwarna biru kehijauan yang dapat dideteksi dengan  spektrofoto-meter pada kondisi: lmax 574 nm;  pH 3; konsentrasi TMK 0,0002 M, dan waktu tunggu selama 4–10 menit. perbandingan volume pereaksi: Hg(II), bufer pH 3, TMK 0,002 M, H2O bebas ion adalah 1:1:1:7. Dari hasil penelitian menunjukkan bahwa metode ini telah memenuhi validitas, yaitu: linieritas 0,05–2,0 mg/L, limit deteksi 0,008 mg/L, dan % recovery antara 98% – 102%. Gangguan matriks akibat adanya ion–ion Au(III), Ag(I), Pd(II), Cu(II), Co(II), dan Fe(II) dapat dieliminasi dengan metode ekstraksi pelarut dan adisi standar. Metode adisi standar terbukti mampu memberikan data hasil pengukuran yang dapat dipercaya pada a 5%, yaitu untuk sampel buatan sebesar (0,053 ± 0,001) mg/L, air sungai (0,034 ± 0,004) mg/L, dan sedimen sebesar (4,172 ± 0,050) mg/kg. Dari hasil penelitian ini dapat disimpulkan bahwa metode ekstraksi pelarut dan adisi standar mampu mengeliminasi gangguan matriks pada analisis merkuri sebagai kompleks Hg-TMK secara spektrofotometriKata kunci: Metode analisis merkuri, Thio Michler’s keton, eliminasi, gangguan matriks  Abstract. A research  of analysis method for determination of mercury through formation of complex with 4,4'-bis(dimethylamino)thiobenzophenone TMK has been conducted. The green blue complex compound can be detected with spectrophoto-meter in conditions: lmax 574 nm, buffer acetate pH 3, concentration of TMK 0,0002 M, and the absorbance of complex remains stable for 4–10 minutes. The formula of reagents volume for: Hg(II): buffer acetate pH 3: TMK 0,002 M : de-ionized water is 1:1:1:7. This method is valid, with parameters such as linearity 0.05–2.00 mg/L, limit of detection 0.008 mg/L, and recovery in the range 98%-102%. Matrix interferences that are caused by Au(III), Ag(I), Pd(II), Cu(II), Co(II), and Fe(III) ions can be eliminated with solvent extraction and standard addition methods. Standard addition method is able to give data of trusty measurement result at a 5%, that is for synthesis sample as (0.053 ±  0.001) mg/L, river water (0.034 ± 0.004) mg/L, and for sediment (4.172 ± 0.050) mg/kg. From the result of this research, it can be concluded that solvent extraction and standard addition methods are able to eliminated matrix interferences in mercury analysis as Hg-TMK complex spectrophotometrically Key waords: mercury analysis method, Thio Michler’s ketone, elimination, matrix interferences

scholarly journals Molecular Diagnostic of Ochratoxin A with Specific Aptamers in Corn and Groundnut via Fabrication of A Microfluidic Device

2021 ◽  
Author(s):  
Deepshikha Shahdeo ◽  
Azmat Ali Khan ◽  
Amer M Alanazi ◽  
Yun Suk Huh ◽  
Shruti Shukla ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Limit Of Detection ◽  
Colorimetric Assay ◽  
Animal Health ◽  
Colorimetric Detection ◽  
Molecular Diagnostic ◽  
Detection Range ◽  
Vis Spectroscopy ◽  
Wide Range ◽  
Analytical Device

Abstract Ochratoxin A (OTA) is one of the predominant mycotoxins that contaminate a wide range of food commodities. In the present study, a 36-mer aptamer was used as a molecular recognition element coupled with gold nanoparticles (AuNPs) for colorimetric detection of OTA in a microfluidic paper-based analytical device (µPADs). The µPADs consisted of three zones: control, detection, and sample, interconnected by channels. The biophysical characterizations of aptamer conjugated AuNPs were done by UV-vis spectroscopy (UV-vis), dynamic Light Scattering (DLS), and transmission electron microscopy (TEM). The developed colorimetric assay for OTA showed a limit of detection of 242, 545, and 95.69 ng/mL in water, corn, and groundnut, respectively. The HPLC detection method achieved acceptable coefficient in standard curves (r2 = 0.9995), better detection range, and recovery rates in spiked corn and groundnut samples as 43.61 ± 2.18% to 87.10 ± 1.82% and 42.01 ± 1.31% to 86.03 ± 2.64% after multiple sample extractions and cleanup steps. However, the developed µPADs analytical device had the potent ability to rapidly detect OTA without any extraction pre-requirement, derivatization, and cleanup steps, thus illustrating its feasibility in the animal health sector, agricultural, and food industries.

scholarly journals Ultra violet spectrophotometric analysis of Paracetamol, Diclofenac and Tramadol drugs in mixture

2019 ◽  
Vol 24 (3) ◽  
pp. 52
Author(s):  
Eesa M. Thalij1 ◽  
Sarhan A. Salman2 ◽  
, Hasan. M. Hasan1
Keyword(s):  
Limit Of Detection ◽  
Ultra Violet ◽  
Standard Addition ◽  
Spectrophotometric Analysis ◽  
Standard Curve ◽  
Limit Of Quantitation ◽  
Naoh Solution ◽  
Curve Method ◽  
Standard Curve Method ◽  
Tablet Dosage

The aim of this research was  develop and validate an analytical method by Uv spectrophotometric technique for quantitative determination of paracetamol (PAR), diclofenac or voltarine (DIC) and tramadol or tramal (TRA) in tablet dosage form, paracetamol analysis is based on the absorbance maxima were found to be at 243 nm when dissolved in 0.1N H2SO4 as a sample and in 0.1N NaOH solution as a blank,. Quantitative of PAR in sample is achieved by standard addition methods and three ways calculations were used to estimate the amount in the tablet, the expected content per tablet were equal to  (365.60, 361.984, 358.415 mg) and the results were acceptable when compared with original quantity in tablet(350 mg). The method was compared with standard curved method, showed that it is obeyed Beer – lambert law in the concentration range of 0.1–1 µg/ml for standard addition and standard curve methods, with a correlation coefficient of 0.9980 and o.9944. The limit of detection (LOD) for PAR was 0.036 µg/ml while limit of quantitation (LOQ) 0.119 µg/ml, the recovery of three procedure A, B, C of standard addition and standard curve were (104.40, 103.42, 102.40  and 92.995 %) for PAR ,it was found that the results obtained from the standard addition method were better than the result obtained from the standard curve method. The amount of (DIC) and (TRA) drug in tablet sample calculated depending on the  absorbance (A) at 273 nm to give the value 47.44 mg and 47.6 mg per tablet are acceptable when compared with the value of the original quantity in tablet (50mg) and the recovery of the method was found to be (95.2 and 96.0 % ) respectively, the principle of  the method based on the  (A) of mixture at this λ is a total A of the two drugs, which owns different intensity at this λ at different percentages and that apply to the sample and standard for this drugs. Finally this can applied successfully for routine analysis.    http://dx.doi.org/10.25130/tjps.24.2019.047

scholarly journals Dual-Modal Assay Kit for the Qualitative and Quantitative Determination of the Total Water Hardness Using a Permanent Marker Fabricated Microfluidic Paper-Based Analytical Device

Chemosensors ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 97
Author(s):  
Oyejide Damilola Oyewunmi ◽  
Seyed Hamid Safiabadi-Tali ◽  
Sana Jahanshahi-Anbuhi
Keyword(s):  
Ethylenediaminetetraacetic Acid ◽  
Limit Of Detection ◽  
Low Cost ◽  
Water Hardness ◽  
Sample Introduction ◽  
World Health ◽  
Total Hardness ◽  
Quantitative Detection ◽  
Qualitative And Quantitative ◽  
Analytical Device

A dip-and-read microfluidic paper-based analytical device (µPAD) was developed for the qualitative and quantitative detection of the total hardness of water. To create well-defined hydrophobic barriers on filter paper, a regular office printer and a commercially available permanent marker pen were utilized as a quick and simple technique with easily accessible equipment/materials to fabricate µPAD in new or resource-limited laboratories without sophisticated equipment. After a wettability and barrier efficiency analysis on the permanent marker colors, the blue and green ink markers exhibited favorable hydrophobic properties and were utilized in the fabrication of the developed test devices. The device had five reaction and detection zones modeled after the classification given by the World Health Organization (WHO), so qualitatively it determined whether the water was ‘soft’, ‘moderately hard’, ‘hard’, or ‘very hard’ by changing color from blue to pink in about 3 min. The device was also used to introduce an alternative colorimetric reaction for quantitative analysis of the water hardness without the need for ethylenediaminetetraacetic acid (EDTA) and without compromising the simplicity and low cost of the device. The developed µPAD showed a calculated limit of detection (LOD) of 0.02 mM, which is at least 80% less than those of commercially available test strips and other reported µPADs, and the results of the real-world samples were consistent with those of the standard titration (with EDTA). In addition, the device exhibited stability for 2 months at room and frigid condition (4 °C) and at varying harsh temperatures from 25 to 100 °C. The results demonstrate that the developed paper-based device can be used for rapid, on-site analysis of water with no interferences and no need for a pipette for sample introduction during testing.

scholarly journals Analysis of the Chloroacetanilide Herbicides in Water Using SPME with CAR/PDMS and GC/ECD

2005 ◽  
Vol 88 (4) ◽  
pp. 1236-1241 ◽  
Author(s):  
Ying-Ming Hwang ◽  
Yih-Gang Wong ◽  
Wu-Hsiung Ho
Keyword(s):  
Humic Acid ◽  
Ph Value ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Standard Addition ◽  
Electron Capture Detection ◽  
Detection Analysis ◽  
Salt Addition ◽  
Chloroacetanilide Herbicides ◽  
Relative Standard

Abstract The solid-phase microextraction (SPME) technique using a 75 mm film of carboxen/polydimethylsiloxane was applied to the analysis of chloroacetanilide herbicides (acetochlor, alachlor, butachlor, metolachlor, and propachlor) residues. The feasibility of SPME with gas chromatography electron capture detection analysis has been evaluated. The effects of experimental parameters such as magnetic stirring, salt addition, humic acid addition, pH value, and extraction time, as well as desorption temperature and time, were investigated. Analytical parameters such as linearity, repeatability and limit of detection were also evaluated. The inhibition of humic acid to the extraction of chloroacetanilide herbicides was observed. A standard addition method for calibration was recommended to reduce deviations caused by matrix interferences. The proposed method provided a simple and rapid analytical procedure for chloroacetanilide herbicides in water with limits of detection 0.002–0.065 μg/L for deionized water, and 0.005–0.22 μg/L for farm water. The relative standard deviations (n = 5) for analyses of farm water were 7–20% for 0.5 μg/L chloroacetanilide herbicides. This application was illustrated by the analysis of sample collected from farm water in the Chung-hwa area, Taiwan.

scholarly journals Multiplex Real-Time Polymerase Chain Reaction for Simultaneous Quantification ofSalmonellaspp.,Escherichia coli, andStaphylococcus aureusin Different Food Matrices: Advantages and Disadvantages

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Amanda Teixeira Sampaio Lopes ◽  
George Rêgo Albuquerque ◽  
Bianca Mendes Maciel
Keyword(s):  
Escherichia Coli ◽  
Real Time ◽  
Limit Of Detection ◽  
Microbiological Quality ◽  
Rapid Screening ◽  
Multiplex Qpcr ◽  
Advantages And Disadvantages ◽  
Simultaneous Quantification ◽  
Polymerase Chain ◽  
Food Matrices

Quantitative real-time polymerase chain reactions (qPCRs) of the most prevalent bacteria causing foodborne diseases worldwide, such asSalmonellaspp.,Escherichia coli, andStaphylococcus aureus,can be an important tool for quantitative microbial risk assessment, which requires numerical data to determine the level of contamination at a specific stage of food production. However, most of qPCR assays described in the literature for these pathogens are qualitative; their objective is pathogen detection and not pathogen quantification. Thus, the aim of our work was to develop a qPCR for the simultaneous quantification ofSalmonellaspp.,E. coli, andS. aureusand to propose its use in the analysis of foods, as a tool for microbiological quality monitoring. For this, a multiplex qPCR was standardized for the simultaneous quantification of specific fragments of target genes (ssf,phoA, andnuc) corresponding to each one of the mentioned bacteria. The limit of detection of the technique was 13, 10, and 12 gene copies forssf,phoA, andnuc, respectively; standard curves showed R2> 0.99, with efficiencies ranging from 99 to 110%, and inter- and intraexperiment reproducibility presented a low coefficient of variation in all trials. This methodology was applied in different food matrices (milk, ground beef, and oyster meat), and the results were compared with official microbiological culture methodology and with ready-to-use test. Advantages and disadvantages of each methodology used in this study are pointed out. We suggest that this multiplex qPCR can be used as a rapid screening technique for the analysis of food microbiological quality.

Nonspecificity of Urinary Lead Measurements by Atomic Absorption Spectroscopy

1969 ◽  
Vol 15 (12) ◽  
pp. 1124-1131 ◽  
Author(s):  
Robert J Segal
Keyword(s):  
Atomic Absorption ◽  
Organic Compounds ◽  
Hollow Cathode ◽  
Atomic Absorption Spectroscopy ◽  
Standard Addition ◽  
Cathode Tube ◽  
Increased Sensitivity ◽  
Standard Additions ◽  
Urinary Lead ◽  
Hollow Cathode Tube

Abstract Lead measurements by direct AAS at 217 nm on a pooled urine sample gave values of 57 µg/l by the method of standard additions. In contrast, dithizone procedures gave values of 15-20 µg/l. Studies demonstrated that various urine salts and organic compounds contributed to the absorbance at 217 nm. These native urine materials also give a similar absorbance value at 220 nm, a line not related to lead emitted by the lead hollow cathode tube. Thus, correction of the nonlead absorbance was possible by subtracting the A220 from A217. Utilizing this correction, the standard addition procedure gave values of 12 µg/l. The correction technic was also applied to the lead isolation-concentration technic of Kopito and Shwachman (3) which employs bismuth coprecipitation. The simplicity of operations, increased sensitivity and reproducibility obtained by coupling the AAS correction technic with bismuth coprecipitation recommends it as a method for serious consideration.

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