scholarly journals A Sensitive and Specific ESI-Positive LC–MS/MS Method for the Quantitation of Estrogens in Human Serum in Under Three Minutes

2020 ◽  
Author(s):  
Aaron Stella ◽  
Subhakar Dey
Keyword(s):  
Reference Material ◽  
Sample Preparation ◽  
Certified Reference Materials ◽  
Method Comparison ◽  
Ammonium Fluoride ◽  
Liquid Extraction ◽  
Analyte Signal ◽  
Liquid Liquid Extraction ◽  
Mobile Phases ◽  
High Level

Abstract Amplifex Diene reagent was employed to derivatize estradiol (E2) to enhance the analyte signal at low picogram concentrations. This derivatization enabled measurement of E2 (and other estrogens) in ESI+ mode, earlier retention times for analytes than other methods, avoidance of MS harmful ammonium fluoride in mobile phases, and an LLOQ below 1 pg/mL. The sample preparation workflow involved liquid–liquid extraction followed by Amplifex Diene derivatization for 10 min at ambient temperature. Samples were chromatographed using a standard C18 column and analyzed using a SCIEX 6500+ mass spectrometer. The assay calibrators were prepared in-house, traceable to certified reference materials, and ranged from 1.29 to 624 pg/mL. A method comparison to samples from the CDC HoSt program yielded a correlation coefficient of 0.9858 and bias of −1.37%. The LLOQ using certified reference material was 0.66 pg/mL. The intra-run precision was <9.00% for low- and high-level samples, whereas the inter-run precision was 15.2 and 5.43% for low- and high-level samples, respectively. No interference from other clinically relevant steroids was found. Amplifex Diene derivatized E2 and estrone (E1) was found to be stable for over 6 months, both refrigerated and frozen.

scholarly journals Application of the Dehydration Homogeneous Liquid–Liquid Extraction (DHLLE) Sample Preparation Method for Fingerprinting of Honey Volatiles

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2277
Author(s):  
Piotr M. Kuś ◽  
Igor Jerković
Keyword(s):  
Carboxylic Acid ◽  
Sample Preparation ◽  
Preparation Method ◽  
Liquid Extraction ◽  
Sample Preparation Method ◽  
Phenyllactic Acid ◽  
Homogeneous Liquid ◽  
Liquid Liquid Extraction ◽  
Wide Range ◽  
Chemical Groups

Recently, we proposed a new sample preparation method involving reduced solvent and sample usage, based on dehydration homogeneous liquid–liquid extraction (DHLLE) for the screening of volatiles and semi-volatiles from honey. In the present research, the method was applied to a wide range of honeys (21 different representative unifloral samples) to determine its suitability for detecting characteristic honey compounds from different chemical classes. GC-FID/MS disclosed 130 compounds from different structural and chemical groups. The DHLLE method allowed the extraction and identification of a wide range of previously reported specific and nonspecific marker compounds belonging to different chemical groups (including monoterpenes, norisoprenoids, benzene derivatives, or nitrogen compounds). For example, DHLLE allowed the detection of cornflower honey chemical markers: 3-oxo-retro-α-ionols, 3,4-dihydro-3-oxoedulan, phenyllactic acid; coffee honey markers: theobromine and caffeine; linden honey markers: 4-isopropenylcyclohexa-1,3-diene-1-carboxylic acid and 4-(2-hydroxy-2-propanyl)cyclohexa-1,3-diene-1-carboxylic acid, as well as furan derivatives from buckwheat honey. The obtained results were comparable with the previously reported data on markers of various honey varieties. Considering the application of much lower volumes of very common reagents, DHLLE may provide economical and ecological advantages as an alternative sample preparation method for routine purposes.

The Benefits and Limitations of Methods Development in Solid Phase Extraction: Mini Review

2014 ◽  
Vol 69 (4) ◽  
Author(s):  
Norfahana Abd-Talib ◽  
Siti Hamidah Mohd-Setapar ◽  
Aidee Kamal Khamis
Keyword(s):  
Sample Preparation ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Liquid Extraction ◽  
Phase Extraction ◽  
Methods Development ◽  
Liquid Liquid Extraction ◽  
Target Analytes ◽  
Two Phases ◽  
Preparation Techniques

Over recent years, there has been an explosive growth of sample preparation techniques. Sample preparation is in most cases meant to be the isolation online or offline concentration of some components of interest or target analytes. Solid phase extraction (SPE) is a very popular technique nowadays in sample preparation. The principal is quite similar with liquid- liquid extraction (LLE) which involves partition of solutes between two phases. But, there are some differences between them and some benefits and limitations of difference types of SPE technique like presented in this paper.

scholarly journals Comparison of two sample preparation procedures for HPLC determination of ochratoxin A

2009 ◽  
Vol 61 (4) ◽  
pp. 639-644 ◽  
Author(s):  
Gorica Vukovic ◽  
Snezana Pavlovic ◽  
M.S. Ristic
Keyword(s):  
Sample Preparation ◽  
Phosphoric Acid ◽  
Ochratoxin A ◽  
Chromatographic Determination ◽  
Liquid Extraction ◽  
Immunoaffinity Column ◽  
Maize Flour ◽  
Liquid Liquid Extraction ◽  
Immunoaffinity Columns

In preparation of samples for chromatographic determination of ochratoxin A, two types of columns were used for sample cleanup (SPE and immunoaffinity columns). The first method consisted of liquid-liquid extraction with a mixture of chloroform and phosphoric acid, followed by ion-exchange cleanup on Waters Oasis MAX columns. The sec?ond method consisted of extraction with a mixture of water and methanol, followed by LCTech OtaCLEAN immunoaf?finity column cleanup. Recoveries of the methods were determined at three levels in three repetitions for maize flour, and they were 84% (%RSD = 19.2) for the first method of sample preparation and 101% (%RSD = 2.2) for the second method. Values of LOQ for OTA were 0.25 and 1.00 ?g/kg for the IAC and SPE clean-up procedures, respectively. Both methods comply with present regulations, but the MAX sample clean-up procedure should be used as an alternative, since the immunoaffinity column clean-up procedure is characterized by better reproducibility, accuracy, and efficiency.

Development and Validation of a Method for Quantification of 28 Psychotropic Drugs in Postmortem Blood Samples by Modified Micro-QuEChERS and LC–MS-MS

2020 ◽  
Author(s):  
Taís B Rodrigues ◽  
Damila R Morais ◽  
Victor A P Gianvecchio ◽  
Elvis M Aquino ◽  
Ricardo L Cunha ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Forensic Toxicology ◽  
Sample Volume ◽  
Weighting Factor ◽  
Liquid Extraction ◽  
Analytical Toxicology ◽  
Limit Of Quantification ◽  
Liquid Liquid Extraction ◽  
Postmortem Blood ◽  
Development And Validation

Abstract The development of new sample preparation alternatives in analytical toxicology leading to quick, effective, automated and environmentally friendly procedures is growing in importance. One of these alternatives is the QuEChERS, originally developed for the analysis of pesticide residues, producing cleaner extracts than liquid–liquid extraction, and easier separation of aqueous and organic phases. However, there are few published studies on the miniaturization of this technique for forensic toxicology, especially in postmortem analysis. We developed and validated a modified micro-QuEChERS and LC–MS-MS assay to quantify 16 antidepressants, 7 antipsychotics and 3 metabolites and semi-quantify norfluoxetine and norsertraline in postmortem blood. The calibration curve was linear from 1 to 500 ng/mL, achieved an r > 0.99, with all standards quantifying within ±15% of target except ±20% at the limit of quantification of 1 ng/mL for 26 substances. The F test was applied to evaluate if the variance between replicates remained constant for all calibrators. Six weighting factors were analyzed (1/x, 1/x2, 1/x0,5, 1/y, 1/y2 and 1/y0,5), with the weighting factor with the lowest sum of residual regression errors (1/x2) selected. No endogenous or exogenous interferences were observed. Method imprecision and bias were <19.0% and 19.7%, respectively. Advantages of this method include a low sample volume of 100 µL, simple but effective sample preparation and a rapid 8.5-min run time. The validated analytical method was successfully applied to the analysis of 100 authentic postmortem samples.

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