10 research outputs found
Derivatization Strategies in Flavor Analysis: An Overview over the Wine and Beer Scenario
No full textWine and beer are the most appreciated and consumed beverages in the world. This success is mainly due to their characteristic taste, smell, and aroma, which can delight consumer’s palates. These olfactory characteristics are produced from specific classes of volatile compounds called “volatile odor-active compounds” linked to different factors such as age and production. Given the vast market of drinking beverages, the characterization of these odor compounds is increasingly important. However, the chemical complexity of these beverages has led the scientific community to develop several analytical techniques for extracting and quantifying these molecules. Even though the recent “green-oriented” trend is directed towards direct preparation-free procedures, for some class of analytes a conventional step like derivatization is unavoidable. This review is a snapshot of the most used derivatization strategies developed in the last 15 years for VOAs’ determination in wine and beer, the most consumed fermented beverages worldwide and among the most complex ones. A comprehensive overview is provided for every method, whereas pros and cons are critically analyzed and discussed. Emphasis was given to miniaturized methods which are more consistent with the principles of “green analytical chemistry”
Aroma determination in alcoholic beverages: Green MS-based sample preparation approaches
No full textAroma determination in alcoholic beverages has become a hot research topic due to the ongoing effort to obtain quality products, especially in a globalized market. Consumer satisfaction is mainly achieved by balancing several aroma compounds, which are mixtures of numerous volatile molecules enclosed in challenging matrices. Thus, sample preparation strategies for quality control and product development are required. They involve several steps including copious amounts of hazardous solvents or time-consuming procedures. This is bucking the trend of the ever-increasing pressure to reduce the environmental impact of analytical chemistry processes. Hence, the evolution of sample preparation procedures has directed towards miniaturized techniques to decrease or avoid the use of hazardous solvents and integrating sampling, extraction, and enrichment of the targeted analytes in fewer steps. Mass spectrometry coupled to gas or liquid chromatography is particularly well suited to address the complexity of these matrices. This review surveys advancements of green miniaturized techniques coupled to mass spectrometry applied on all categories of odor-active molecules in the most consumed alcoholic beverages: beer, wine, and spirits. The targeted literature consider progresses over the past 20 years
MACCHINA PER ANALISI CHIMICA COMPRENDENTE LA COMBINAZIONE DELLA SPETTROMETRIA DI MASSA A IONIZZAZIONE ELETTRONICA CON LA CROMATOGRAFIA LIQUIDA
No full textTyrosol and Hydroxytyrosol Determination in Extra Virgin Olive Oil with Direct Liquid Electron Ionization-Tandem Mass Spectrometry
No full textExtra virgin olive oil (EVOO) is one of the main ingredients of the Mediterranean diet. It is claimed as a functional food for its unique content of health-promoting compounds. Tyrosol (Tyr), Hydroxytyrosol (Htyr), and their phenolic derivatives present in EVOO show beneficial properties, and their identification and quantification, both in their free form and after the hydrolysis of more complex precursors, are important to certify its quality. An alternative method for quantifying free and total Tyr and Htyr in EVOO is presented using an LC–MS interface based on electron ionization (EI), called liquid electron ionization (LEI). This method requires neither sample preparation nor chromatography; the sample is diluted and injected. The selectivity and sensitivity were assessed in multiple reaction monitoring mode (MRM), obtaining confirmation and quantification in actual samples ranging from 5 to 11 mg/Kg for the free forms and from 32 to 80 mg/Kg for their total amount after hydrolysis. Two MS/MS transitions were acquired for both compounds using the Q/q ratios as confirmatory parameters. Standard addition calibration curves demonstrated optimal linearity and negligible matrix effects, allowing a correct quantification even without expensive and difficult to find labeled internal standards. After several weeks of operation, the system’s repeatability was excellent, with an intraday RSD (%) spanning from five to nine and an interday RSD (%) spanning from 9 to 11
Condensed Phase Membrane Introduction Mass Spectrometry: A Direct Alternative to Fully Exploit the Mass Spectrometry Potential in Environmental Sample Analysis
No full textMembrane introduction mass spectrometry (MIMS) is a direct mass spectrometry technique used to monitor online chemical systems or quickly quantify trace levels of different groups of compounds in complex matrices without extensive sample preparation steps and chromatographic separation. MIMS utilizes a thin, semi-permeable, and selective membrane that directly connects the sample and the mass spectrometer. The analytes in the sample are pre-concentrated by the membrane depending on their physicochemical properties and directly transferred, using different acceptor phases (gas, liquid or vacuum) to the mass spectrometer. Condensed phase (CP) MIMS use a liquid as a medium, extending the range to new applications to less-volatile compounds that are challenging or unsuitable to gas-phase MIMS. It directly allows the rapid quantification of selected compounds in complex matrices, the online monitoring of chemical reactions (in real-time), as well as in situ measurements. CP-MIMS has expanded beyond the measurement of several organic compounds because of the use of different types of liquid acceptor phases, geometries, dimensions, and mass spectrometers. This review surveys advancements of CP-MIMS and its applications to several molecules and matrices over the past 15 years
Pesticide exposure during pregnancy, like nicotine, affects the brainstem α7 nicotinic acetylcholine receptor expression, increasing the risk of sudden unexplained perinatal death
No full textThis study indicates the impact of nicotine and pesticides (organochlorine and organophosphate insecticides
used in agriculture) on neuronal α7-nicotinic acetylcholine receptor expression in brainstem regions receiving
cholinergic projections in human perinatal life. An in-depth anatomopathological examination of the autonomic
nervous systemand immunohistochemistry to analyze the α7-nicotinic acetylcholine receptor expression in the
brainstem from 44 fetuses and newborns were performed. In addition, the presence of selected agricultural
pesticides in cerebral cortex samples of the victims was determined by specific analytical procedures.
Hypodevelopment of brainstem structures checking the vital functions, frequently associated with
α7-nicotinic acetylcholine receptor immunopositivity and smoke absorption in pregnancy, was observed in
high percentages of victims of sudden unexpected perinatal death. In nearly 30% of cases however the mothers
never smoked, but lived in rural areas. The search for pesticides highlighted in many of these cases traces of
both organochlorine and organophosphate pesticides. We detain that exposition to pesticides in pregnancy
produces homologous actions to those of nicotine on neuronal α7-nicotinic acetylcholine receptor, allowing to
developmental alterations of brainstem vital centers in victims of sudden unexplained death
Sudden Infant Death With Area Postrema Lesion Likely Due to Wrong Use of Insecticide
No full textWe report a noteworthy case of a 7-month-old infant who suddenly and abstract
unexpectedly died during her sleep. After a complete postmortem examination,
review of the clinical history, and detailed death scene investigation, the death
remained unexplained, leading to a diagnosis of sudden infant death syndrome.
However, an extensive review of the brainstem neuropathology revealed a severe
alteration in the area postrema (a highly vascular structure lying at the base of
the fourth ventricle outside of the blood-brain barrier). The alteration was
likely due to massive and repeated to a common household insecticide in the last
few weeks of life. These results provide an explanation for this sudden infant
death, allowing a differential diagnosis from sudden infant death syndrome
Determination of Selected Endocrine Disrupting Compounds in Human Fetal and Newborn Tissues by GC-MS
No full textEndocrine disrupting compounds (EDCs) include
organochlorine pesticides (OCPs), organophosphate pesticides
(OPPs), carbamate pesticides, and plasticizers, such as
bisphenol A (BPA). They persist in the environment because
of their degradation resistance and bioaccumulate in the body
tissues of humans and other mammals. Many studies are
focused on the possible correlation between in utero exposure
to EDCs and adverse health hazards in fetuses and newborns.
In the last decade, environmental pollution has been considered
a possible trigger for Sudden Infant Death Syndrome
(SIDS) and Sudden Intrauterine Unexplained Death
Syndrome (SIUDS), the most important death-causing syndromes
in fetuses and newborns in developed countries. In
this work, a rapid and sensitive analytical method was developed
to determine the level of OCPs and OPPs, carbamates,
and phenols in human fetal and newborn tissues (liver and
brain) and to unveil the possible presence of non-targeted
compounds. The target analytes where selected on the basis
of their documented presence in the Trentino-Alto Adige
region, an intensive agricultural area in northern Italy. A
liquid-solid extraction procedure was applied on human and
animal tissues and the extracts, after a solid phase extraction
(SPE) clean-up procedure, were analyzed by gas chromatography
coupled to a quadrupole mass spectrometric detector
(GC-qMS). A GC-TOFMS (time-of-flight) instrument, because
of its higher full-scan sensitivity, was used for a parallel
detection of non-targeted compounds. Method validation included accuracy, precision, detection, and quantification
limits (LODs; LOQs), and linearity response using swine liver
and lamb brain spiked at different concentrations in the range
of 0.4–8000.0 ng/g. The method gave good repeatability and
extraction efficiency. Method LOQs ranged from 0.4–4.0 ng/g
in the selected matrices. Good linearity was obtained over four
orders of magnitude starting from LOQs. Isotopically labeled
internal standards were used for quantitative calculations. The
method was then successfully applied to the analysis of liver
and brain tissues from SIUDS and SIDS victims coming from
the above mentioned region
Microfluidic water-assisted trap focusing method for ultra-large volume injection in reversed-phase nano-liquid chromatography coupled to electron ionization tandem-mass spectrometry
No full textHerein we present an efficient, column-switching method that relies on a custom-made T-union passive diffusion micromixer to assist water dilution and promote trap solute focusing of a high sample volume dissolved in pure organic solvent using a 0.075 mm i.d. nano-LC column. This method allows injecting 20 μL (or higher) of sample volume, speeding up the analysis time, with a 400-fold increase of the limits of quantitation for selected compounds. Five pesticides in different media were used as model compounds, and the analyses were carried out with a triple quadrupole mass spectrometer equipped with a Liquid Electron Ionization (LEI) LC-MS interface working in multiple reaction monitoring (MRM) mode. The system microfluidics were investigated using COMSOL modeling software. Robustness of the entire system was evaluated using a post-extraction addition soil extracts with limits of detection values spanning from 0.10 to 0.45 μg/L. Reproducible results in terms of peak area, peak shape, and retention times were achieved in soil matrix. Repeatability test on peak area variations were lower than 10%
Electron Ionization LC-MS: What Is It and Why Use It?
No full textElectron ionization (EI) is a unique and advantageous ionization technique typically employed in gas chromatography-mass spectrometry (GC-MS). Here are presented two different approaches to benefit from EI in liquid chromatography-mass spectrometry (LC-MS). The first EI-based interface exploits EI of vibrationally cold molecules in supersonic molecular beams (SMBs) (hence named Cold EI). This system and its operational methods are centred on pneumatic spray formation of the liquid flow in a heated vaporization chamber, full thermal vaporization of the sample compounds and their subsequent EI as vibrationally cold molecules in the SMB after their supersonic expansion from a supersonic nozzle. Cold EI mass spectrum exhibits the standard EI fragments with enhanced molecular ion. The second EI-based interface is called Liquid-EI (LEI), and it is based on the nebulization of the liquid phase carrying the analytes inside a specifically designed region where the vaporization of solutes occurs at atmospheric pressure before entering the high-vacuum ion source. LEI guarantees more flexibility towards low volatile and thermolabile molecules analysis in respect to previous versions of this approach. The fine control of the vaporization temperature and the inertness of the new vaporization surface can enhance the overall interface performances. LEI generates typical EI mass spectra for the undoubted identification of targeted and nontargeted analytes. The two systems feature broad linear dynamic range, uniform response both for polar and nonpolar compounds and lack of matrix ion suppression effects that plague electrospray ionization and atmospheric pressure chemical ionization. These features are shown, described and demonstrated in different examples and applications
