研究目的
The simultaneous determination of cochineal and erythrosine in cherries in syrup using excitation-emission fluorescence data and three-way PARAFAC decomposition, handling the quenching effect caused by cochineal on erythrosine.
研究成果
The method successfully determined cochineal and erythrosine in cherries in syrup despite quenching and spectral overlap, with errors below 6%. Results were statistically equivalent to HPLC/DAD, demonstrating the method's reliability for food safety monitoring.
研究不足
The method requires a calibration set with binary mixtures, which may be time-consuming. Quenching effect by cochineal on erythrosine complicates quantification, and the approach may not be directly applicable to other matrices without adaptation. Filter selection affected recovery rates, indicating potential matrix interferences.
1:Experimental Design and Method Selection:
The study used excitation-emission fluorescence matrices (EEMs) and three-way PARAFAC decomposition to resolve overlapping signals and quenching effects. Calibration sets included binary mixtures of analytes to account for quenching.
2:Sample Selection and Data Sources:
Samples included pure standards of cochineal and erythrosine, binary mixtures, and pitted cherries in syrup from a local supermarket. Data were fluorescence EEMs and HPLC/DAD chromatograms.
3:List of Experimental Equipment and Materials:
Equipment included a PerkinElmer LS 50B Luminiscence spectrometer, Agilent 1260 Infinity HPLC system, pH-meter, vortex stirrer, filters, and quartz cells. Materials included cochineal powder, erythrosine B, methanol, sodium tetraborate decahydrate, hydrochloric acid, and deionized water.
4:Experimental Procedures and Operational Workflow:
Standard solutions were prepared in borate buffer. Samples were homogenized, extracted with buffer, filtered, and measured. Fluorescence measurements were taken at specific excitation and emission wavelengths. HPLC conditions involved a C18 column with methanol-water mobile phase.
5:Data Analysis Methods:
PARAFAC decomposition was performed using MATLAB and PLS_Toolbox. Statistical analysis included regression models, decision limits (CCα), and capability of detection (CCβ) calculated with DETARCHI and STATGRAPHICS.
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Luminiscence spectrometer
LS 50B
PerkinElmer
Used to register excitation-emission fluorescence measurements.
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HPLC system
1260 Infinity
Agilent
Used for chromatographic analysis with diode array detection.
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Quartz cell
SUPRASIL
PerkinElmer
Used for fluorescence measurements with a cell volume of 3.5 mL.
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pH-meter
micropH 2002
Crison
Used to measure pH of buffer solutions.
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Vortex stirrer
V05 series
LBX Instruments
Used for stirring samples during extraction.
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Water purification system
Milli-Q Direct 8
Millipore
Used to obtain deionized water.
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Filter paper
Whatman qualitative
Whatman
Used for filtering samples.
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Syringe filter
Polypropylene, 0.22 μm pore size
Membrane Solutions
Used for filtering samples before HPLC injection.
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