Magnetic headspace adsorptive extraction of chlorobenzenes prior to thermal desorption gas chromatography-mass spectrometry

Vidal, Lorena; Ahmadi, Mazaher; Fernández, Elena; Madrakian, Tayyebeh; Canals, Antonio

doi:10.1016/j.aca.2017.04.002

Cited by 22 publications

(4 citation statements)

References 37 publications

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“…Figure shows that the NaOH concentration (Factor C) has the largest effect on the chemiluminescence signal, but none of the variables show statistically significant effects, as in other previous works. , The same figure shows that the luminol and the NaOH concentrations (Factors B and C) and the reaction time (Factor A) showed a positive effect. In order to explain the positive effect of these variables, it is necessary to know the oxidation reaction mechanism of the luminol in an alkaline medium.…”

Section: Results and Discussionsupporting

confidence: 78%

Free Glycerol Sensing in Biodiesel: Automatic System Based on Sequential Enzymatic Reactions Using a Fit-for-Purpose Chemiluminescence Detection Chamber

et al. 2019

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The transesterification reaction to produce biodiesel generates a residual content of free glycerol, which may cause several problems to the engines. According to the international specification, the free glycerol determination involves a derivatization step followed by chromatographic analysis, which is done by advanced laboratories. Argentina is one of the largest biodiesel producers in the world, and part of this production is carried out by small and medium-sized producers. For those producers, this analysis is expensive and requires a considerable amount of time because there are few laboratories and they are localized far from the production site. This work proposes an alternative method for free glycerol determination in biodiesel samples taking advantage of automation, the use of an economic and available kit of enzymes, and a rapid and simple detection which was improved by the use of a fit-for-purpose chemiluminescence detection chamber designed in our laboratory. Quantification of free glycerol was performed by chemiluminescence at 425 nm after the reaction of hydrogen peroxide and luminol in the presence of Co2+. The hydrogen peroxide was generated by sequential enzymatic reactions based on the catalytic effect of glycerol kinase and glycerol phosphate oxidase. The calibration curve was linear in the 0.0045–0.0200% (w/w) range (r = 0.9910), and the sample throughput of the automatic system was 8 h–1. The geometrical configuration of the designed chemiluminescence detection chamber allowed an appropriate mixture of the reagents, due to a coupled efficient mixing system, and a highly sensitive detection (LOD value: 0.0013% (w/w)). The enzymatic method was applied for the determination of glycerol in commercial (soybean) and laboratory syntethized biodiesel samples (corn and sunflower). The trueness of the method was evaluated by comparison with the reference method (EN 14105), and a nonsignificative difference between them was observed (n = 6; P = 0.05).

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Section: Results and Discussionsupporting

confidence: 78%

Free Glycerol Sensing in Biodiesel: Automatic System Based on Sequential Enzymatic Reactions Using a Fit-for-Purpose Chemiluminescence Detection Chamber

et al. 2019

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“…Alustiza et al used magnetic headspace adsorptive extraction (MAG-HSAE) followed by thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) to investigate potential VOC biomarkers from the stool samples from patients with CRC, adenomatous polyps, and healthy controls [ 92 ]. MAG-HSAE is a subtype of solid-phase extraction technique in which one end of a small neodymium magnet contains graphene oxide decorated with iron oxide magnetic nanoparticles that function as a sorbent, in which VOCs from the headspace can be directly collected and analyzed with a coupled modality (e.g., TD-GC-MS here) [ 102 ]. Using this technique, they found significantly elevated levels of p-Cresol and 3(4H)-dibenzofuranone,4a,9b-dihydro-8,9b-dimethyl- (3(4H)-DBZ) in the CRC group compared to the polyp and control groups.…”

Section: Detection Of Gastrointestinal Illnesses By Vocsmentioning

confidence: 99%

Volatile Organic Compound Assessment as a Screening Tool for Early Detection of Gastrointestinal Diseases

et al. 2023

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Gastrointestinal (GI) diseases have a high prevalence throughout the United States. Screening and diagnostic modalities are often expensive and invasive, and therefore, people do not utilize them effectively. Lack of proper screening and diagnostic assessment may lead to delays in diagnosis, more advanced disease at the time of diagnosis, and higher morbidity and mortality rates. Research on the intestinal microbiome has demonstrated that dysbiosis, or unfavorable alteration of organismal composition, precedes the onset of clinical symptoms for various GI diseases. GI disease diagnostic research has led to a shift towards non-invasive methods for GI screening, including chemical-detection tests that measure changes in volatile organic compounds (VOCs), which are the byproducts of bacterial metabolism that result in the distinct smell of stool. Many of these tools are expensive, immobile benchtop instruments that require highly trained individuals to interpret the results. These attributes make them difficult to implement in clinical settings. Alternatively, electronic noses (E-noses) are relatively cheaper, handheld devices that utilize multi-sensor arrays and pattern recognition technology to analyze VOCs. The purpose of this review is to (1) highlight how dysbiosis impacts intestinal diseases and how VOC metabolites can be utilized to detect alterations in the microbiome, (2) summarize the available VOC analytical platforms that can be used to detect aberrancies in intestinal health, (3) define the current technological advancements and limitations of E-nose technology, and finally, (4) review the literature surrounding several intestinal diseases in which headspace VOCs can be used to detect or predict disease.

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“…The TD system was adjusted according to previously published works [20,27] as follows: splitless mode; desorption temperature, from 25 ºC (0.…”

Section: Td-gc-ms Conditionsmentioning

confidence: 99%

Hydrophilic magnetic ionic liquid for magnetic headspace single-drop microextraction of chlorobenzenes prior to thermal desorption-gas chromatography-mass spectrometry

2017

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A new, fast, easy to handle, and environmentally friendly magnetic headspace single-drop microextraction (Mag-HS-SDME) based on a magnetic ionic liquid (MIL) as an extractant solvent is presented. A small drop of the MIL 1-ethyl-3-methylimidazolium tetraisothiocyanatocobaltate(II) ([Emim][Co(NCS)]) is located on one end of a small neodymium magnet to extract nine chlorobenzenes (1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene, 1,2,3,4-tetrachlorobenzene, 1,2,4,5-tetrachlorobenzene, and pentachlorobenzene) as model analytes from water samples prior to thermal desorption-gas chromatography-mass spectrometry determination. A multivariate optimization strategy was employed to optimize experimental parameters affecting Mag-HS-SDME. The method was evaluated under optimized extraction conditions (i.e., sample volume, 20 mL; MIL volume, 1 μL; extraction time, 10 min; stirring speed, 1500 rpm; and ionic strength, 15% NaCl (w/v)), obtaining a linear response from 0.05 to 5 μg L for all analytes. The repeatability of the proposed method was evaluated at 0.7 and 3 μg L spiking levels and coefficients of variation ranged between 3 and 18% (n = 3). Limits of detection were in the order of nanograms per liter ranging from 4 ng L for 1,4-dichlorobenzene and 1,2,3,4-tetrachlorobenzene to 8 ng L for 1,2,4,5-tetrachlorobenzene. Finally, tap water, pond water, and wastewater were selected as real water samples to assess the applicability of the method. Relative recoveries varied between 82 and 114% showing negligible matrix effects. Graphical abstract Magnetic headspace single-drop microextraction followed by thermal desorption-gas chromatography-mass spectrometry.

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Magnetic headspace adsorptive extraction of chlorobenzenes prior to thermal desorption gas chromatography-mass spectrometry

Cited by 22 publications

References 37 publications

Free Glycerol Sensing in Biodiesel: Automatic System Based on Sequential Enzymatic Reactions Using a Fit-for-Purpose Chemiluminescence Detection Chamber

Free Glycerol Sensing in Biodiesel: Automatic System Based on Sequential Enzymatic Reactions Using a Fit-for-Purpose Chemiluminescence Detection Chamber

Volatile Organic Compound Assessment as a Screening Tool for Early Detection of Gastrointestinal Diseases

Hydrophilic magnetic ionic liquid for magnetic headspace single-drop microextraction of chlorobenzenes prior to thermal desorption-gas chromatography-mass spectrometry

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