scholarly journals Qualitative analysis of Sudan IV in edible palm oil

2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Sampson Saj Andoh ◽  
Tarmo Nuutinen ◽  
Cheetham Mingle ◽  
Matthieu Roussey
Keyword(s):  
Raman Spectroscopy ◽  
Qualitative Analysis ◽  
Palm Oil ◽  
Surface Enhanced Raman Spectroscopy ◽  
International Agency ◽  
Chemometric Methods ◽  
Frequency Range ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Sudan Iv

Abstract Background Palm oil is one of the most useful vegetable available. Sudan IV dye is used as hue enhancer in palm oil despite the ban as food colorant due to its carcinogenicity and mutagenicity by the International Agency for Research on Cancer (IARC). Methods Surface enhanced Raman spectroscopy (SERS) coupled with chemometric methods was applied to detect the presence of Sudan IV in some edible palm oil samples. Results We studied the samples within the 1200–1800 cm− 1 Raman frequency range. In predicting adulteration, we used 1388 cm− 1 Raman peak that is associated with Sudan IV as our marker. We were able to confirm adulteration in four of the five palm oil samples provided by the Food and Drug Authority of Ghana. Conclusions With these methods, we confirmed the results from Food and Drug Authorities of Ghana by proving that there were indeed Sudan IV adulteration in some palm oil samples.

scholarly journals Rapid Detection of Pesticide Residues in Paddy Water Using Surface-Enhanced Raman Spectroscopy

Sensors ◽  
2019 ◽  
Vol 19 (3) ◽  
pp. 506 ◽  
Author(s):  
Shizhuang Weng ◽  
Wenxiu Zhu ◽  
Ronglu Dong ◽  
Ling Zheng ◽  
Fang Wang
Keyword(s):  
Raman Spectroscopy ◽  
Pesticide Residue ◽  
Pesticide Residues ◽  
Rapid Detection ◽  
Surface Enhanced Raman Spectroscopy ◽  
Support Vector ◽  
Chemometric Methods ◽  
Paddy Water ◽  
Surface Enhanced ◽  
Surface Enhanced Raman

Pesticide residue in paddy water is one of the main factors affecting the quality and safety of rice, however, the negative effect of this residue can be effectively prevented and reduced through early detection. This study developed a rapid detection method for fonofos, phosmet, and sulfoxaflor in paddy water through chemometric methods and surface-enhanced Raman spectroscopy (SERS). Residue from paddy water samples was directly used for SERS measurement. The obtained spectra from the SERS can detect 0.5 mg/L fonofos, 0.25 mg/L phosmet, and 1 mg/L sulfoxaflor through the appearance of major characteristic peaks. Then, we used chemometric methods to develop models for the intelligent analysis of pesticides, alongside the SERS spectra. The classification models developed by K-nearest neighbor identified all of the samples, with an accuracy of 100%. For the quantitative analysis, the partial least squares regression models obtained the best predicted performance for fonofos and sulfoxaflor, and the support vector machine model provided optimal results, with a root-mean-square error of validation of 0.207 and a coefficient of determination of validation of 0.99952, for phosmet. Experiments for actual contaminated samples also showed that the above models predicted the pesticide residue values with high accuracy. Overall, using SERS with chemometric methods provided a simple and convenient approach for the detection of pesticide residues in paddy water.

scholarly journals Detection of Pirimiphos-Methyl in Wheat Using Surface-Enhanced Raman Spectroscopy and Chemometric Methods

Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1691 ◽  
Author(s):  
Shizhuang Weng ◽  
Shuan Yu ◽  
Ronglu Dong ◽  
Jinling Zhao ◽  
Dong Liang
Keyword(s):  
Raman Spectroscopy ◽  
Density Functional ◽  
Surface Enhanced Raman Spectroscopy ◽  
Gas Chromatography Mass Spectrometry ◽  
Support Vector ◽  
Raman Signal ◽  
Chemometric Methods ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Pirimiphos Methyl

Pesticide residue detection is a hot issue in the quality and safety of agricultural grains. A novel method for accurate detection of pirimiphos-methyl residues in wheat was developed using surface-enhanced Raman spectroscopy (SERS) and chemometric methods. A simple pretreatment method was conducted to extract pirimiphos-methyl residue from wheat samples, and highly effective gold nanorods were prepared for SERS measurement. Raman peaks assignment was calculated using density functional theory. The Raman signal of pirimiphos-methyl can be detected when the concentrations of residue in wheat extraction solution and contaminated wheat is as low as 0.2 mg/L and 0.25 mg/L, respectively. Quantification of pirimiphos-methyl was performed by applying regression models developed by partial least squares regression, support vector machine regression and random forest with principal component analysis using different preprocessed methods. As for the contaminated wheat samples, the relative deviation between gas chromatography-mass spectrometry value and predicted value is in the range of 0.10%–6.63%, and predicted recovery is 94.12%–106.63%, ranging from 23.93 mg/L to 0.25 mg/L. Results demonstrated that the proposed SERS method is an effective and efficient analytical tool for detecting pirimiphos-methyl in wheat with high accuracy and excellent sensitivity.

Qualitative analysis of some alkanethiols on Au nanoparticles during SERS

RSC Advances ◽  
2016 ◽  
Vol 6 (15) ◽  
pp. 12131-12142 ◽  
Author(s):  
R. A. Harris ◽  
M. Mlambo ◽  
P. S. Mdluli
Keyword(s):  
Raman Spectroscopy ◽  
Qualitative Analysis ◽  
Au Nanoparticles ◽  
Surface Enhanced Raman Spectroscopy ◽  
Surface Enhanced ◽  
Enhancement Factors ◽  
Surface Enhanced Raman ◽  
Surfactant Systems

The surface enhanced Raman spectroscopy enhancement factors (SERS EFs) for different AuNP–surfactant systems are measured and the observed trend is theoretically and qualitatively investigated.

Bacterial detection and differentiation via direct volatile organic compound sensing with surface enhanced Raman spectroscopy

2017 ◽  
Author(s):  
Caitlin S. DeJong ◽  
David I. Wang ◽  
Aleksandr Polyakov ◽  
Anita Rogacs ◽  
Steven J. Simske ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Bacterial Infections ◽  
Direct Detection ◽  
Point Of Care ◽  
Surface Enhanced Raman Spectroscopy ◽  
E Coli ◽  
Recent Emergence ◽  
Surface Enhanced ◽  
Volatile Organic ◽  
Surface Enhanced Raman

Through the direct detection of bacterial volatile organic compounds (VOCs), via surface enhanced Raman spectroscopy (SERS), we report here a reconfigurable assay for the identification and monitoring of bacteria. We demonstrate differentiation between highly clinically relevant organisms: <i>Escherichia coli</i>, <i>Enterobacter cloacae</i>, and <i>Serratia marcescens</i>. This is the first differentiation of bacteria via SERS of bacterial VOC signatures. The assay also detected as few as 10 CFU/ml of <i>E. coli</i> in under 12 hrs, and detected <i>E. coli</i> from whole human blood and human urine in 16 hrs at clinically relevant concentrations of 10<sup>3</sup> CFU/ml and 10<sup>4</sup> CFU/ml, respectively. In addition, the recent emergence of portable Raman spectrometers uniquely allows SERS to bring VOC detection to point-of-care settings for diagnosing bacterial infections.

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