scholarly journals Determination of Aflatoxin in Processed Dried Cassava Root: Validation of a New Analytical Method for Cassava Flour

2010 ◽  
Vol 93 (6) ◽  
pp. 1882-1887 ◽  
Author(s):  
G J Benoit Gnonlonfin ◽  
David R Katerere ◽  
Yann Adjovi ◽  
Leon Brimer ◽  
Gordon S Shephard ◽  
...  
Keyword(s):  
Analytical Method ◽  
Optimal Performance ◽  
Immunoaffinity Column ◽  
Critical Factors ◽  
Toxin Concentration ◽  
Cassava Flour ◽  
Cassava Root ◽  
Fluorescence Determination ◽  
Postcolumn Derivatization

Abstract A new method that uses HPLC with a photochemical reactor for enhanced detection was developed and validated for the determination of aflatoxins in cassava flour. Samples were spiked with a mixture of four aflatoxins at 5, 10, and 20 g/kg mixed with either 1 or 5 g NaCl and extracted with methanolwater (80 20, v/v) by shaking for 10 or 30 min. An immunoaffinity column was used for cleanup. HPLC with postcolumn derivatization, for enhancement of aflatoxin fluorescence, and fluorescence determination were used for quantitation of the toxin concentration. The method was validated for recovery, linearity, and precision at the three concentrations tested. Recovery ranges were 5270, 6985, and 8089 for the spiking levels of 5.0, 10.0, and 20.0 g/kg, respectively. It appears that the amount of salt (NaCl) and the shaking time are critical factors in this method; optimal performance was obtained when 1 g salt was used and the shaking time was 10 min. The good linearity and precision of the method allowed baseline separation from interferences, e.g., coumarins.

Aflatoxins in Brazilian Peanut Confection

2016 ◽  
Vol 99 (3) ◽  
pp. 830-834 ◽  
Author(s):  
Maria H Iha ◽  
Isaura A Okada ◽  
Rita C Briganti ◽  
Camila A Mini ◽  
Mary W Trucksess
Keyword(s):  
Fluorescence Enhancement ◽  
Public Health Problem ◽  
Current Method ◽  
Immunoaffinity Column ◽  
Paulo State ◽  
Fluorescence Determination ◽  
The Mean ◽  
Aflatoxin B2 ◽  
Postcolumn Derivatization

Abstract The study's objectives were to evaluate a method for the determination of aflatoxins (AFs) in the Brazilian peanut confection “Paçoca” and to apply the method in investigating AF concentrations in Paçoca marketed in São Paulo State throughout 2013. Results of another survey conducted between 1994 and 2002 with another method were also reported. The current method consists of immunoaffinity column cleanup, LC with postcolumn derivatization for AF fluorescence enhancement, and fluorescence determination for the toxins. The mean recovery and mean RSDr values were 88.6 and 7.9%, respectively. The LODs for aflatoxin B1, aflatoxin B2, aflatoxin G1, and aflatoxin G2 were 0.04, 0.01, 0.02, and 0.01 ng/g; and the LOQs were 0.15, 0.04, 0.07, and 0.04 ng/g, respectively. Results of the two survey studies indicate that the contamination of AFs in Paçoca remains a public health problem. In the 2013 survey, 71 of 100 samples (71%) had AFs contamination ranging from 0.3 to 41.8 ng/g, with 12 samples (12%) containing >20 ng/g of the toxins, whereas in the 1994–2002 survey, 73 of 150 samples (51%) had AFs contamination ranging from 9 to 1439 ng/g with 65 samples (45%) containing levels >20 ng/g.

scholarly journals Immunoaffinity Column Cleanup with Liquid Chromatography for Determination of Aflatoxin B1 in Corn Samples: Interlaboratory Study

2007 ◽  
Vol 90 (3) ◽  
pp. 765-772 ◽  
Author(s):  
Carlo Brera ◽  
Francesca Debegnach ◽  
Valentina Minardi ◽  
Elena Pannunzi ◽  
Barbara De Santis ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Aflatoxin B1 ◽  
Interlaboratory Study ◽  
Precolumn Derivatization ◽  
Immunoaffinity Column ◽  
Relative Standard ◽  
Postcolumn Derivatization

Abstract An interlaboratory study was conducted to evaluate the effectiveness of an immunoaffinity column cleanup liquid chromatography (LC) method for the determination of aflatoxin B1 levels in corn samples, enforced by European Union legislation. A test portion was extracted with methanolwater (80 + 20); the extract was filtered, diluted with phosphate-buffered saline solution, filtered on a microfiber glass filter, and applied to an immunoaffinity column. The column was washed with deionized water to remove interfering compounds, and the purified aflatoxin B1 was eluted with methanol. Aflatoxin B1 was separated and determined by reversed-phase LC with fluorescence detection after either pre- or postcolumn derivatization. Precolumn derivatization was achieved by generating the trifluoroacetic acid derivative, used by 8 laboratories. The postcolumn derivatization was achieved either with pyridinium hydrobromide perbromide, used by 16 laboratories, or with an electrochemical cell by the addition of bromide to the mobile phase, used by 5 laboratories. The derivatization techniques used were not significantly different when compared by the Student's t-test; the method was statistically evaluated for all the laboratories. Five corn sample materials, both spiked and naturally contaminated, were sent to 29 laboratories (22 Italian and 7 European). Test portions were spiked with aflatoxin B1 at levels of 2.00 and 5.00 ng/g. The mean values for recovery were 82% for the low level and 84% for the high contamination level. Based on results for spiked samples (blind pairs at 2 levels) as well as naturally contaminated samples (blind pairs at 3 levels), the values for relative standard deviation for repeatability (RSDr) ranged from 9.9 to 28.7%. The values for relative standard deviation for reproducibility (RSDR) ranged from 18.6 to 36.8%. The method demonstrated acceptable within- and between-laboratory precision for this matrix, as evidenced by the HorRat values.

Development of an analytical method for the determination of sterigmatocystin in grains using LCMS after immunoaffinity column purification

2014 ◽  
Vol 30 (2) ◽  
pp. 123-129 ◽  
Author(s):  
R. Sasaki ◽  
M. Z. Hossain ◽  
N. Abe ◽  
M. Uchigashima ◽  
T. Goto
Keyword(s):  
Analytical Method ◽  
Immunoaffinity Column

Determination of Aflatoxins B1, B2, G1, and G2 in Olive Oil, Peanut Oil, and Sesame Oil Using Immunoaffinity Column Cleanup, Postcolumn Derivatization, and Liquid Chromatography/Fluorescence Detection: Collaborative Study

2012 ◽  
Vol 95 (6) ◽  
pp. 1689-1700 ◽  
Author(s):  
Lei Bao ◽  
Chengzhu Liang ◽  
Mary W Trucksess ◽  
Yanli Xu ◽  
Ning Lv ◽  
...  
Keyword(s):  
Olive Oil ◽  
Lower Layer ◽  
Collaborative Study ◽  
Sesame Oil ◽  
Peanut Oil ◽  
Immunoaffinity Column ◽  
Fluorescence Detector ◽  
Repeatability And Reproducibility ◽  
Postcolumn Derivatization

Abstract The accuracy, repeatability, and reproducibility characteristics of a method using immunoaffinity column (IAC) cleanup with postcolumn derivatization and LC with a fluorescence detector (FLD) for determination of aflatoxins (AFs; sum of AFs B1, B2, G1, and G2) in olive oil, peanut oil, and sesame oil have been established in a collaborative study involving 15 laboratories from six countries. Blind duplicate samples of blank, spiked at levels ranging from 0.25 to 20.0 μg/kg for AF, were analyzed. A naturally contaminated peanut oil sample was also included. Test samples were extracted with methanol–water (55 + 45, v/v). After shaking and centrifuging, the lower layer was filtered, diluted with water, and filtered through glass microfiber filter paper. The filtrate was then passed through an IAC, and the toxins were eluted with methanol. The toxins were then subjected to RPLC-FLD analysis after postcolumn derivatization. Average recoveries of AFs from olive oil, peanut oil, and sesame oil ranged from 84 to 92% (at spiking levels ranging from 2.0 to 20.0 μg/kg); of AFB1 from 86 to 93% (at spiking levels ranging from 1.0 to 10.0 μg/kg); of AFB2 from 89 to 95% (at spiking levels ranging from 0.25 to 2.5 μg/kg); of AFG1 from 85 to 97% (at spiking levels ranging from 0.5 to 5.0 μg/kg); and of AFG2 from 76 to 85% (at spiking levels ranging from 0.25 to 2.5 μg/kg). RSDs for within-laboratory repeatability (RSDr) ranged from 3.4 to 10.2% for AF, from 3.5 to 10.9% for AFB1, from 3.2 to 9.5% for AFB2, from 6.5 to 14.9% for AFG1, and from 4.8 to 14.2% for AFG2. RSDs for between-laboratory reproducibility (RSDR) ranged from 6.1 to 14.5% for AF, from 7.5 to 15.4% for AFB1, from 7.1 to 14.6% for AFB2, from 10.8 to 18.1% for AFG1, and from 7.6 to 23.7% for AFG2. Horwitz ratio values were ≤2 for the analytes in the three matrixes.

X-ray fluorescence determination of zinc sulfate in acidic zinc plating electrolyte

2020 ◽  
Vol 86 (10) ◽  
pp. 18-22
Author(s):  
K. N. Vdovin ◽  
K. G. Pivovarova ◽  
N. A. Feoktistov ◽  
T. B. Ponamareva
Keyword(s):  
Zinc Sulfate ◽  
Zinc Coating ◽  
Electrolyte Composition ◽  
Complexometric Titration ◽  
X Ray ◽  
Fluorescence Determination ◽  
Zinc Plating ◽  
Zinc Determination

Zinc sulfate is the main component in the composition of the acidic zinc plating electrolyte. Deviation in the electrolyte composition from the optimum content leads to destabilization of the electrolysis process and deteriorate the quality of the resulting zinc coating. The proper quality of a zinc coating obtained by galvanic deposition can be ensured only with timely monitoring and adjustment of the electrolyte composition. A technique of X-ray fluorescence determination of zinc (in terms of zinc sulfate) in an acidic zinc plating electrolyte is proposed. The study was carried out using an ARL Quant’X energy dispersive spectrometer (Thermo Fisher Scientific, USA) with a semiconductor silicon-lithium detector. The features of the spectrometer design are presented. The optimal parameters of excitation and detection of zinc radiation were specified when the electrolyte sample was diluted 1:1000. The ZnKα1 line was used as an analytical line. The plotted calibration graph is linear, the correlation coefficient being 0.999234. The results of zinc determination according to the developed method were compared with the data of the reference method of complexometric titration to prove the reliability of the procedure. The results are characterized by good convergence and accuracy. The proposed method of X-ray fluorescence zinc determination in a zinc plating electrolyte equals complexometric titration in the limiting capabilities and even exceeds the latter in terms of the simplicity of sample preparation and rapidity. The developed method of X-ray fluorescence determination of zinc is implemented in analysis of the electrolyte used in the continuous galvanizing unit at «METSERVIS LLC».

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