Simultaneous Determination of Seven Anions of Interest in Raw Jatropha curcas Oil by Ion Chromatography

Abstract

Various ions are of interest to the quality of biodiesel feedstock and products. In this study, a simple and labor-saving analytical method was developed to directly and simultaneously measure seven anions of interest in oil, utilizing an ion chromatography system with function of sample matrix elimination. Various eluent profiles were explored and calibration curves were made to analyze 13 raw Jatropha curcas oils for their contents of formate, acetate, nitrite, nitrate, sulfite, sulfate and phosphate. A 23 min program was found to sufficiently separate all the ions, and linear correlation higher than 99% was achieved for all the ions except formate (98.6%). High diversity was found in both the presence and concentration range of these ions. Formate, nitrate, and phosphate were more prevalent among the ions tested, such that 12, 10, and 11 samples showed their presence, respectively. Nitrite was found in only two samples with the concentrations lower than 10 mg kg–1. Formate concentration ranged from 0 to over 3000 mg kg–1, and nitrate and phosphate showed ranges of 0 to 100 and 0 to 300 mg kg–1, respectively. Acetate was less common than formate, and its concentration was universally lower (0 to 500 mg kg–1). In addition, the occurrence of acetate and nitrite seemed to be correlated to that of formate and nitrate, respectively, whereas sulfite and sulfate showed mutual exclusion. This method showed reasonably good detection limits and reproducibility, that concentrations of around 0.2 mg L–1 can be detected in the organic samples, and in most cases the ratio of standard deviation to average was below 25%. However, for phosphate, the accuracy and reproducibility need further improvement, possibly by decreasing sample dilution ratio and optimizing eluent profile.

Identification of Extra Virgin Olive Oils Modified by the Addition of Soybean Oil, Using Ion Chromatography

“…This result is consistent with the literature data, which reports that the formic acid is the preponderant short chain carboxylic acid, among the other products of the lipid oxidation. [18][19][20][22][23][24][25][26] The adulterant (SO) content changes the fatty acid composition of the blend (EVOO + SO). Therefore, it is possible to state that the concentrations of formic and acetic acids, produced in the lipid oxidation, are influenced by the fatty acid composition of the sample.…”

“…22 The analytical methods that have been employed to determine formic and acetic acids in lipid samples include capillary electrophoresis 23 and ion chromatography. [18][19][20][24][25][26] In the present work, two methods were studied to determine the modification of EVOO with refined soybean oil. The first one was based on the IP, determined by Rancimat.…”

Bioamide-Decorated Polyfluoreneisocyanide: Preparation from Benzoxazine-Isocyanide Mechanochemistry Postmodification and Application as an Active Modifier for Pb2+/NO2– Electrochemical Probing

“…Therefore, the effective detection of Pb 2+ and NO 2 – in water samples is crucial for environmental protection and human health development. Pb 2+ /NO 2 – probing methods include atomic absorption spectrometry, spectrophotometric method, ionic chromatography, fluorescence, high-performance liquid chromatography, inductively coupled plasma emission spectroscopy, and electrochemical detection. − As a useful supplement for traditional probing protocols, electrochemical probing displays some beneficial characteristics of a wide selection scope for electrodes and modifying materials, high sensitivity and low detection limits, excellent signaling specificity, simple operation, and involvement of relatively inexpensive equipment, − attracting widespread attention from researchers. However, most of the reports on Pb 2+ /NO 2 – electrochemical probes are focused on the involvement of active modifiers that can facilitate the detection of these two pollutants separately. − No electrochemical probing material with the adaptability for both Pb 2+ /NO 2 – detection has been reported up to now.…”

Polyethylenimine-Capped CdS Quantum Dots for Sensitive and Selective Detection of Nitrite in Vegetables and Water

“…For example, 6.5 × 10 –5 M is set to be the maximum limit of nitrite in drinking water, which is recommended by the World Health Organization. To date, various methods have been reported to determine nitrite including chemiluminescence, , spectrofluorimetric, , electrochemical, , chromatographic, and capillary electrophoresis , methods. However, some methods still have limitations on sensitivity, selectivity, simplicity, and feasibility for the detection of trace amounts of nitrite; or instance, some reported works could not distinguish nitrite from the common coexisting nitrate ions. , Spectrofluorimetric methods have attracted interest owing to their high selectivity and sensitivity, as well as simple operability and low-cost advantages .…”