Simultaneous analysis of esters and acylglycerols in biodiesel by high-performance liquid chromatography with refractive index detection

Santos, Bruno Lima dos; Silva, Kissya Kropf da; Santos, Amanda Pereira Franco dos; Andrade, Débora França de; d’Avila, Luiz Antonio

doi:10.1080/10826076.2016.1225221

Cited by 7 publications

(7 citation statements)

References 14 publications

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“…Some methods have been used to analyze biodiesel, most notably: GC, [ 7,8 ] GC with flame ionization detector, [ 5,9 ] thin‐layer chromatography, [ 7,10 ] high‐performance liquid chromatography, [ 11–21 ] gas chromatography‐mass spectrometry, [ 3,22 ] nuclear magnetic resonance, [ 23–27 ] near‐infrared spectroscopy, [ 28,29 ] and size‐exclusion chromatography (SEC). [ 4,30–25 ]…”

Section: Introductionmentioning

confidence: 99%

Simultaneous Analysis of Mono‐, Di‐, Triacylglycerols, and Fatty Acid Methyl Esters in Biodiesel by Size‐Exclusion Chromatography

Costa

Souza

Santos

et al. 2021

Euro J Lipid Sci & Tech

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The purpose of this study is to develop and validate a method based on size‐exclusion chromatography (SEC) for the simultaneous determination of fatty acid methyl esters (FAME), monoacylglycerols (MAG), diacylglycerols (DAG), and triacylglycerols (TAG) in biodiesel. The proposed method presents good linearity. The limits of detection are 0.26% mass for FAME, 0.02% mass for MAG, 0.01% mass for DAG, and 0.02% mass for TAG. The limits of quantification are 0.78% mass for FAME, 0.06% mass for MAG, 0.01% mass for DAG, and 0.06% mass for TAG. Accuracy evaluated by recovery yielded values ranging from 98.93% to 117.67%. Precision is evaluated by repeatability (%), which is ranged from 0.03% to 13.67%. The proposed SEC method proves effective in determining the FAME, MAG, DAG, and TAG content of standard samples, and the paired t‐test shows that the results obtained were statistically similar to the gas chromatography (GC) values. The method also has some advantages over the reference GC methods, since it obtains the content for each class analyzed, irrespective of its components. Also, it does not require derivatization, which makes it easier and also quicker (15 min) than the 60 min taken by the two reference methods, and it does not need an internal standard, which makes it cheaper. Practical Applications: Size exclusion chromatography (SEC) is an efficient method for simultaneous and quantitative determination of fatty acid methyl esters (FAME), monoacylglycerols (MAG), diacylglycerols and triacylglycerols (TAG). The method present itself as an alternative to reference methods (ASTM D 6584 and ABNT NBR 15764) based on gas chromatography (GC). The proposed method shows advantages compared to reference methods, once it makes possible to determine the content of each constituent class in samples, regardless of its components, what makes the peak integration easier. Beyond that, previous sample derivatization is unnecessary, what makes the method simpler, cheaper and faster (15 min) than both reference methods that demands together 60 min for analysis (ASTM D 6584 for MAG, DAGa and TAG and ABNT NBR 15764 for FAME analysis).

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Section: Introductionmentioning

confidence: 99%

Simultaneous Analysis of Mono‐, Di‐, Triacylglycerols, and Fatty Acid Methyl Esters in Biodiesel by Size‐Exclusion Chromatography

Costa

Souza

Santos

et al. 2021

Euro J Lipid Sci & Tech

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“…High-performance liquid chromatography (HPLC) has also been used to monitor biodiesel quality, ,− but few studies have reported on its use in determining the biodiesel content of diesel and the potential adulteration of biodiesel/diesel blends with vegetable oil …”

Section: Introductionmentioning

confidence: 99%

Determination of the Biodiesel Content on Biodiesel/Diesel Blends and Their Adulteration with Vegetable Oil by High-Performance Liquid Chromatography

et al. 2019

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Biodiesel content on biodiesel/diesel blends is obtained by determining the band intensity of CO bond in the fatty acid methyl esters (FAME) of the biodiesel by mid-infrared spectroscopy (reference method: EN 14078, 2014). The potential for biodiesel/diesel blends to be adulterated with vegetable oils constitutes a limitation of the reference method’s capacity to accurately quantify the biodiesel content in these blends since vegetable oils, composed primarily of triacylglycerols, also contain the CO bond. This study employed normal-phase high-performance liquid chromatography with a refractive index detector (NP-HPLC-RI) to quantify the biodiesel in biodiesel/diesel blends and detect potential adulterations of these blends with vegetable oils. Two calibration curves (4 to 12% vol and 5 to 30% vol) were plotted for the biodiesel quantification based on which 12 verification samples were analyzed (samples prepared at different concentrations from the calibration curves), as well as 20 samples of commercial diesel, acquired at gas stations in the southeast region of Brazil. The NP-HPLC-RI method presented good analytical performance in terms of linearity, limit of detection (LOD), limit of quantification (LOQ), precision (repeatability), accuracy (recovery), and robustness. Linearity was determined by the coefficient of determination (R 2) for concentrations of biodiesel and vegetable oil in diesel varying from 4 to 12% vol (R 2 = 0.9924 and R 2 = 0.9950, respectively) and from 5 to 30% vol (R 2 = 0.9968 and R 2 = 0.9962, respectively). The LOD and LOQ for the quantification of the biodiesel were 0.08 and 0.23% vol, while for the quantification of soybean oil, these values were 0.07 and 0.21% vol, respectively. The recovery values varied from 97.7 ± 1.8% to 107.1 ± 4.1%, indicating good accuracy, and the method proved robust when the temperature was changed from 40 to 35 °C. The paired sample t-test showed the nonexistence of significant differences between the proposed and reference methods (with 95% confidence), indicating the capacity of NP-HPLC-RI to detect and quantify biodiesel and vegetable oil adulterants in samples of diesel both rapidly and effectively, thereby demonstrating its importance for the quality control of this fuel since the current methodology (EN 14078) used in several European Union countries, as well as in Brazil and Argentina, cannot identify this kind of adulteration and cannot accurately analyze the biodiesel content in biodiesel/petrodiesel blends.

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“…Method B was compared with the reference method, gas chromatography with flame ionization detector, recommended by the American Oil Chemists' Society for determining FAMEs in real samples of biodiesel. In 2016, dos Santos et al 22 developed an HPLC-RI method using a mobile phase composed by 85% MeOH and 15% isopropanol/n-hexane (6:3). Analysis time was about 50 min.…”

Section: Introductionmentioning

confidence: 99%

“…A variety of chromatographic and spectroscopic techniques are used to assess the quality of biodiesel, including thin layer chromatography, , gas chromatography with flame ionization detector (GC-FID), − gas chromatography–mass spectrometry, − headspace-based gas chromatography, gas chromatography-differential mobility spectrometry with cluster analysis, high-performance liquid chromatography, − gel permeation chromatography, − supercritical fluid chromatography, near-infrared spectroscopy, , Fourier-transform spectroscopy, , Raman spectroscopy, 13 C NMR, H NMR, − and sequential/flow injection analysis (SIA/FIA). , …”

Section: Introductionmentioning

confidence: 99%

Analysis and Quantitation of Fatty Acid Methyl Esters in Biodiesel by High-Performance Liquid Chromatography

et al. 2018

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The aim of this study was to compare two methods for determining the fatty acid methyl ester content of biodiesel by applying high-performance liquid chromatography (HPLC-UV) and the reference method based on gas chromatography (GC). The samples of biodiesel were also analyzed by 1H NMR. External standards were used for the quantification of fatty acid methyl esters by HPLC-UV. The analytical curves of the methyl oleate, methyl linoleate, and methyl linolenate standards showed good linearity (coefficient of determination ≥ 0.995). Cochran’s test was used to assess the homoscedasticity of the analytical curves. The limits of detection and quantitation were found: 0.0018% mass and 0.0054% mass for methyl oleate, 0.0002% mass and 0.0007% mass for methyl linoleate, and 0.0001% mass and 0.0004% mass for methyl linolenate. The accuracy of the HPLC-UV method was assessed by determining recovery (%), which resulted on values between 81.7 ± 0.2 and 110.9 ± 0.1. Precision was assessed by determining repeatability (%), which was found to be between 0.2 and 1.3. The proposed HPLC-UV method proved efficient in determining the fatty acid methyl ester content of biodiesel and the paired t-test showed it to correlate well with the reference method (GC).

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Simultaneous analysis of esters and acylglycerols in biodiesel by high-performance liquid chromatography with refractive index detection

Cited by 7 publications

References 14 publications

Simultaneous Analysis of Mono‐, Di‐, Triacylglycerols, and Fatty Acid Methyl Esters in Biodiesel by Size‐Exclusion Chromatography

Simultaneous Analysis of Mono‐, Di‐, Triacylglycerols, and Fatty Acid Methyl Esters in Biodiesel by Size‐Exclusion Chromatography

Determination of the Biodiesel Content on Biodiesel/Diesel Blends and Their Adulteration with Vegetable Oil by High-Performance Liquid Chromatography

Analysis and Quantitation of Fatty Acid Methyl Esters in Biodiesel by High-Performance Liquid Chromatography

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