82,400 research outputs found
Ms. Courtney Chartier, RWWL AUC, August 2011
No full textThis video is a conversation with Ms. Courtney Chartier. Ms. Chartier talks about her work on the "New Georgia Encyclopedia" and "Online Voter Education Project." Andrea Jackson, AUC Woodruff Library, is the interviewer
Ms. Neely Terrell, RWWL AUC, March 2012
No full textThis video is a conversation with Ms. Neely Terrell. Ms. Terrell talks about her book, "Super Singles Activate". Anthony Kinsey and Jahnesta Horney, AUC Woodruff Library, are the interviewers
Ms. Felesha Love, Spelman College, January 2016
No full textThis video is a conversation with Felesha Love. Ms. Love talks about her book, "Brave Leap to Freedom: Integrating Mind, Body, and Spirit to Cultivate Healthy Relationships". Jordan Moore, AUC Woodruff Library, is the interviewer
Validation of an LC-MS/MS method for the determination of serum 17-hydroxyprogesterone
No full textopenIntroduzione. Il 17-idrossiprogesterone (17-OHP) è un ormone steroideo, precursore del cortisolo che deriva dal colesterolo. La misurazione del 17-OHP può essere utilizzata per la ricerca, diagnosi e monitoraggio della sindrome surrenale-genitale congenita (CAH) e sindrome dell’ovaio policistico (PCOS) e nella diagnosi di tumori surrenalici androgeno-secernenti. Tradizionalmente, i livelli di 17-OHP sierici vengono determinati con test immunometrici manuali e più recentemente automatizzati ma che presentano una bassa specificità analitica e di conseguenza una inaccuratezza diagnostica. L’utilizzo della cromatografia liquida (HPLC) accoppiata alla spettrometria di massa tandem (LC-MS/MS) permette di avere un'elevata specificità analitica.
Lo scopo di questa tesi è ottimizzare la procedura di preparazione del campione di un metodo “home-made” LC-MS/MS per la determinazione del 17-OHP sierico in modo da renderla implementabile su un preparatore automatico e di poterlo quindi attivare nella routine di laboratorio. Questo metodo poi deve essere validato secondo le linee-guida internazionali, rendendolo conforme allo Standard Internazionale di accreditamento per i laboratori medici ISO 15189:2012.
Materiali e metodi. È stata studiata una procedura di preparazione del campione che prevede una fase iniziale di precipitazione proteica (PP) e una seconda fase di estrazione in fase solida (SPE). Questa procedura è stata inizialmente condotta con cartucce Oasis HLB 1 mL (Waters, USA) per poi utilizzare le piastre SPE Oasis HLB 96-well μElution Plate (Waters, USA). I campioni preparati sono stati analizzati sullo strumento LCMS-8060 (Shimadzu, Japan) utilizzando la colonna ACQUITY UPLC HSS T3, 100Å, 1.8 μm, 2.1 mm X 100 mm (Waters). Il metodo è stato validato secondo le principali linee guida internazionali (CLSI C50-P, CLSI C62, FDA 2018) per i parametri di range di misura analitico, specificità, limite di quantificazione, imprecisione, inesattezza, effetto matrice, comparabilità con il metodo immunometrico e stabilità del campione.
Risultati. Le prestazioni analitiche ottenute dalle prove di validazione soddisfano i criteri di accettabilità richiesti dalle linee-guida internazionali. La procedura di preparazione del campione ottimizzata ha migliorato la risoluzione dei picchi cromatografici, il rapporto segnale/rumore di fondo e il limite di quantificazione. Il metodo sviluppato non risulta né comparabile né correlato con il metodo immunometrico in routine.
Conclusioni. La procedura di preparazione del campione del metodo “home-made” LC-MS/MS per la determinazione dei livelli sierici di 17-OHP è stata ottimizzata per renderla automatizzabile e quindi per poterla implementare nella routine di laboratorio. Il metodo è stato sottoposto a rigorosa validazione secondo le principali linee-guida internazionali e le prestazioni analitiche sono risultate soddisfacenti in base allo scopo d’uso del test
Determination of co-eluted isomers in wine samples by application of MS/MS deconvolution analysis.
No full textIntroduction
Wine is defined as an alcoholic beverage, which is produced by fermentation of fresh grapes or must and the organic acids of beverages are important in several respects. All organic acids have this quality to some degree, but some have their own characteristic flavour, taste or aroma. For example, citric acid has a fresh acid flavour different from that of malic acid, while succinic acid has an unusual salty, bitter taste in addition to its sourness [1]. Wine is also rich in phenolic compounds that are important components with health promoting properties and they also affect organoleptic characteristics, such as colour, astringency and aroma [2]. Recently, Ginjom et al. identify and quantify the individual phenolic compounds present in wine at different wine-making stages from crushing through to bottled and aged wine, produced in different Queensland (Australia) wineries [3]. Interestingly, they were not able to identify a compound (named U1) with a low molecular mass (m/z at 175) and relatively large eluting peak. In a recent paper, our research group have identified in wines two isomeric compounds, corresponding to U1, with molecular weight of 176 Da by using two LC-MS systems, i.e. ion trap (LC-IT) and LC-Q-Orbitrap. The two isomers were organic acids, i.e. 3-isopropylmalic acid (3-IPMA) never identify in wines, and 2-isopropylmalic acid (2-IPMA), never quantify in wines [4]. In this study, the quantification of these two compounds was performed by using LC-IT in ten among red and white wine samples and the average concentrations were determined at 1.78 mg L-1 (range 0.56-4.13 mg L-1) and 23.0 mg L-1 (range 6.7-41.6 mg L-1) of 3-IPMA and 2-IPMA, respectively. The LC-IT method used MS/MS analyses at 0.9 V excitation amplitude by extracting the product ions m/z 73 and m/z 115 for 3-IPMA and 2-IPMA respectively. Thus, the two compounds were separated by using extract ion chromatogram (EIC) of the two characteristics m/z ions. However, the different fragmentation yield of their product ions affects on the quantitation sensitivity. Therefore, to ensure the similar sensitivity between two isomers, their chromatographic separation is needed with increasing the analysis time. In order to ensure the requested specificity of the method, a different approach, based on a series of energy resolved MS/MS experiments, was carried out. By this approach a clear differentiation among all the isomers was obtained but, to emphasize such differences, it was necessary to develop a mathematical algorithm that distinguishes the MS/MS spectra of the isomers. This algorithm (LEDA) consists in the application of matrix of linear regression equations to different experimental data. In our case, the experimental data used were the abundance ratios of product vs. precursor ions selected during the MS/MS method set-up [5-7]. In this way, it was possible to resolve the MS/MS spectra assigning the correct signal to the isomer also for chromatographically unresolved peaks.
Experimental
The LC-MS/MS analysis was carried out using a Varian 1200L triple quadrupole system (Palo Alto, CA, USA) equipped by two Prostar 210 pumps, a Prostar 410 autosampler and an Elettrospray Source (ESI) operating in positive ions. The product ion scan spectra were acquired in the m/z range from 50 to 650, scan time 600 ms; argon was used as collisional gas and the collision energy (CE) was increased stepwise in the range 5 to 40 V. The obtained energy resolved tandem mass spectrometry (ERMS) spectra were employed to study the fragmentation of molecular species of studied isomers and build their breakdown curves. The chromatographic parameters employed to analyse the samples were tuned to minimize the run time. The column used was a Pursuit XRs C18 30 mm length, 2 mm internal diameter and 3 m particle size, at constant flow of 0.25 mL min-1, employing a binary mobile phases elution gradient by 10 min. total run time. The solvents used were 10 mM formic acid in water solution (solvent A) and 10 mM formic acid in acetonitrile (solvent B). The LEDA post-processing mathematical tool was used to guarantee the identification of the isomer present in analyzed samples without their chromatographic separation. The algorithm is based on the consideration that each MS/MS spectrum might be represented as the sum of contribution of each isomer present in the unresolved chromatographic peak. In order to obtain reliable data, the relative abundances of the different product ions were calculated with respect to the reference ion abundance, so that possible misleading results due to compound-dependent different product ion yields are avoided. For this purpose, the available signal of the precursor ion was acquired as reference ion (Ri) which allowed us to obtain the characteristic ratios among the selected product ions for isomer speciation. Therefore, knowing the characteristic abundance ratios of pure isomer, a deconvolution of these spectra is possible based on a series of linear regression equations as follows:
(P_i⁄R_i )_(m )= ∑_(x=1)^n▒〖(P_i⁄R_i )_x*〖[%] 〗_x 〗 (1)
Where:
(Pi/Ri)m: is the abundance ratio between the product (Pi) vs reference ions (Ri) measured (m) in the sample;
(Pi/Ri)x : are the characteristic abundance ratios between the product ion vs reference ion of pure isomers;
[%]x: is the concentration (%) of isomers in the sample.
Precision and accuracy of LEDA algorithm were evaluated by the LC-MS/MS analysis of standard mixtures prepared with different composition of the isomer pair. Then, the LC-MS/MS method with LEDA post-processing tool was apply to the determination of 2-IPMA and 3-IPMA in real samples of wine extracts prepared as reported by Ricciutelli et al [4].
Results
The quantitative results obtained applying the LEDA approach on the abundance ratios of data collected from the MS/MS analysis of the standard mixtures are: accuracy 97.3 % and 96.3 % with a precision, expressed as RSD %, of 1,9 and 1,8 for 2-IPMA and 3-IPMA respectively.
Also the application of LEDA on the wine samples shows a good correlation between the quantitative data obtained with the classical chromatography separation and linear equations deconvolution analysis of MS/MS spectra.
Conclusions
The proposed LC-MS/MS method coupled with mathematical algorithm (LEDA), applied to deconvolute the MS/MS spectra from unresolved chromatographic peak, was effective, allowing the determination of the isomers presents in wine samples. The obtained results confirm the ability of the LEDA approach to deconvolute a mixture of isomers from chromatographically unresolved peaks, allowing short analytic runs and high throughput in processed samples. It is to emphasize that, in the last decade, many investigation were carried out to develop ancillary MS technique able to give a different analytical dimension to the researcher in the field (e.g. ion mobility methods). In this paper we have shown that the energetic dimension of MS/MS experiments can be fruitfully employed to solve isomers characterization and quantification problems.
Reference
G.C. Whiting; Journal of the Institute of Brewing, 82 (1976), pp 84-92.
J.A. Kennedy; Ciencia E Investigacion Agraria, 35 (2008), pp 107–120.
I. Ginjom B. D’Arcy, N. Caffin, M. Gidley; Food Chemistry, 125 (2011), pp 823–834.
M. Ricciutelli, S. Moretti, R. Galarini, G. Sagratini, S. Vittori, S. Lucarini, G. Caprioli; Food Chemistry, 294
(2019), pp. 390-396.
M. Menicatti, L. Guandalini, S. Dei, E. Floriddia, E. Teodori, P. Traldi and G. Bartolucci; Rapid Commun.
Mass Spectrom., 30 (2016), pp 423-432
M. Menicatti, L. Guandalini, S. Dei, E. Floriddia, E. Teodori, P. Traldi and G. Bartolucci; Eur J Mass Spectrom., 22 (2016), pp 235-243
M. Menicatti, M. Pallecchi, S. Bua, D. Vullo, L. Di Cesare Mannelli, C. Ghelardini, F. Carta, C. T. Supuran and G. Bartolucci; J Enzyme Inhib Med Chem., 33 (2018), pp 671-67
Isoflavones in espresso coffee: a new SPE-HPLC-MS/MS method for their determination.
No full textIsoflavones are a group of phenolic compounds that are structurally and functionally similar to 17-estradiol having a weak estrogen-like effects. Epidemiological data suggest that their consumption is associated with the prevention of several hormone-dependent cancers, cardiovascular diseases, osteoporosis, and hot flushes of menopause [1]. Coffee is a extraordinary combination of numerous bioactive compounds with biological and physiological actions on human health, including isoflavones. Several authors reported the determination of some isoflavones, i.e. daidzein, genistein, formononetin, and biochanin A in coffee matrix, and the found concentrations are quite different by comparing the results. Alves et al. proposed an acidic hydrolysis for extracting isoflavones from espresso coffee and used HPLC-DAD for quantifying genistein (180 g/l), daidzein (523 g/l), formononetin (2833 g/l) [2]. Mazur et al. published an article in which reported the analysis by gas chromatography-mass spectrometry (GC-MS) of three isoflavones in six samples of espresso and instant coffee, by finding daidzein (0.1-0.66 mg/kg), genistein (0.15-0.29 mg/kg) and formononetin (0.72-0.78 mg/kg) [3]. Enzymatic hydrolysis, solid phase extraction (SPE) and GC-MS were combined in the work of Thompson et al. for quantifying formononetin (2 g/l), daidzein (1 g/l) and genistein (1 g/l) in prepared coffee [4]. Kuhnle et al. used liquid chromatography-mass spectrometry (LC-MS) for analyzing daidzein, genistein and biochanin A in coffees by finding total isoflavones content of 9130 g/kg (instant coffee powder), 50 g/kg (instant coffee decaffeinated powder), <10 g/kg (infusion and decaffeinated coffee powder) [5]. Sapozhnikova et al. published an article that uses LC-MS/MS method for analyzing genistein (0.9-1.4 mg/kg), daidzein (3.2-5.2 mg/kg) and formononetin (3-6 g/kg) in ground coffee [6]. Basing on different values of isoflavones content in coffe reported in literature, the aim of this work was to develop a new HPLC-MS/MS method for the simultaneous determination of five isoflavones, i.e. daidzein, genistein, genistin, formononetin and biochanin A in espresso coffee. The certified samples of coffee were purchased by Illy Caffè industry. All samples were 100% Arabica. The espresso coffees were prepared by using an automatic machine Iperespresso X7.1 (Illy, Trieste).
1 ml of liquid coffee was extracted with 20 ml of methanol, stored in refrigerator at -20°C for 24 h, then purified by using SPE C18 cartridges (500mg/6ml) and finally injected in HPLC-MS/MS (triple quadrupole as mass analyzer). Separation of the analytes was performed on a Kinetex C18 (50 x 2.10 mm i.d, particle size 2.6 μm, pore diameter 100 Å) by using acetonitrile and formic acid 0.1%/ammonium formiate 5 mM as mobile phase at flow rate of 0.5 ml/min. Calibration curves of six isoflavones in a concentration range 0.001-1 mg/l showed R2 from 0.993 to 0.999. Recovery % calculated at 0.1 mg/l fortification level were in the range 48-106% for all analyzed isoflavones. The validated methodology was applied to the analysis of six samples of certified coffees 100% Arabica. Formononetin was found in a concentration range of 0.40-0.41 g/l, while biochanin A in a range of 0.58-3.26 g/l. Total content of isoflavones was in range of 0.58-3.66 g/l. A HPLC-MS/MS chromatogram of an espresso coffee sample is reported in Fig.1. Samples of coffee 100% Robusta were analyzed to check the content of isoflavones in comparison to 100% Arabica samples
Analysis of a Broad Range of Carbonyl Metabolites in Exhaled Breath by UHPLC-MS
No full textAnalysis of volatile organic compounds (VOCs) in exhaled
breath
(EB) has shown great potential for disease detection including lung
cancer, infectious respiratory diseases, and chronic obstructive pulmonary
disease. Although many breath sample collection and analytical methods
have been developed for breath analysis, analysis of metabolic VOCs
in exhaled breath is still a challenge for clinical application. Many
carbonyl compounds in exhaled breath are related to the metabolic
processes of diseases. This work reports a method of ultrahigh-performance
liquid chromatography coupled with high-resolution mass spectrometry
(UHPLC-MS) for the analysis of a broad range of carbonyl metabolites
in exhaled breath. Carbonyl compounds in the exhaled breath were captured
by a fabricated silicon microreactor with a micropillar array coated
with 2-(aminooxy)ethyl-N,N,N-trimethylammonium (ATM) triflate. A total of six subgroups
consisting of saturated aldehydes and ketones, hydroxy-aldehydes,
and hydroxy-ketones, unsaturated 2-alkenals, and 4-hydroxy-2-alkenals
were identified in the exhaled breath. The combination of a silicon
microreactor for the selective capture of carbonyl compounds with
UHPLC-MS analysis may provide a quantitative method for the analysis
of carbonyls to identify disease markers in exhaled breath
Ultra-trace analysis in complex metallic matrices: ICP-MS techniques for stainless steels and nickel-based alloys
No full textreservedThis thesis investigates the application of Inductively Coupled Plasma Mass Spectrometry (ICP-MS) for the detection of tramp elements in stainless steels and nickel-based alloys produced by Acciaierie Valbruna. Tramp elements such as Pb, Bi, Sb, As, Sn, even at concentrations in the low ppm range, can severely affect mechanical properties, corrosion resistance, and weldability. The results demonstrate the effectiveness of ICP-MS as a reliable tool for monitoring impurities and supporting stringent quality control protocols in the steel industry.This thesis investigates the application of Inductively Coupled Plasma Mass Spectrometry (ICP-MS) for the detection of tramp elements in stainless steels and nickel-based alloys produced by Acciaierie Valbruna. Tramp elements such as Pb, Bi, Sb, As, Sn, even at concentrations in the low ppm range, can severely affect mechanical properties, corrosion resistance, and weldability. The results demonstrate the effectiveness of ICP-MS as a reliable tool for monitoring impurities and supporting stringent quality control protocols in the steel industry
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