scholarly journals Evaluation of a Stable Isotope-Based Direct Quantification Method for Dicamba Analysis from Air and Water Using Single-Quadrupole LC–MS

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3649 ◽  
Author(s):  
Manoj Ghaste ◽  
Nicholas C. Hayden ◽  
Matthew J. Osterholt ◽  
Julie Young ◽  
Bryan Young ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Water Samples ◽  
Detection Method ◽  
Matrix Effects ◽  
Solid Phase ◽  
Internal Standard ◽  
Sample Collection ◽  
Selected Ion Monitoring ◽  
Ms Detection ◽  
Direct Quantification

Dicamba is a moderately volatile herbicide used for post-emergent control of broadleaf weeds in corn, soybean, and a number of other crops. With increased use of dicamba due to the release of dicamba-resistant cotton and soybean varieties, growing controversy over the effects of spray drift and volatilization on non-target crops has increased the need for quantifying dicamba collected from water and air sampling. Therefore, this study was designed to evaluate stable isotope-based direct quantification of dicamba from air and water samples using single-quadrupole liquid chromatography–mass spectrometry (LC–MS). The sample preparation protocols developed in this study utilize a simple solid-phase extraction (SPE) protocol for water samples and a single-step concentration protocol for air samples. The LC–MS detection method achieves sensitive detection of dicamba based on selected ion monitoring (SIM) of precursor and fragment ions and relies on the use of an isotopically labeled internal standard (IS) (D3-dicamba), which allows for calculating recoveries and quantification using a relative response factor (RRF). Analyte recoveries of 106–128% from water and 88–124% from air were attained, with limits of detection (LODs) of 0.1 ng mL−1 and 1 ng mL−1, respectively. The LC–MS detection method does not require sample pretreatment such as ion-pairing or derivatization to achieve sensitivity. Moreover, this study reveals matrix effects associated with sorbent resin used in air sample collection and demonstrates how the use of an isotopically labeled IS with RRF-based analysis can account for ion suppression. The LC–MS method is easily transferrable and offers a robust alternative to methods relying on more expensive tandem LC–MS/MS-based options.

Bioanalytical method development and validation of simultaneous analysis of telmisartan and hydrochlorthiazide in human plasma using LC-MS/MS

2016 ◽  
Vol 5 (03) ◽  
pp. 4862 ◽  
Author(s):  
Mathew George* ◽  
Lincy Joseph ◽  
Arpit Kumar Jain ◽  
Anju V.
Keyword(s):  
Human Plasma ◽  
Retention Time ◽  
High Performance ◽  
Method Development ◽  
Matrix Effects ◽  
Solid Phase ◽  
Internal Standard ◽  
Assay Method ◽  
Buffer System ◽  
Internal Standards

A simple, sensitive, rapid and economic high performance thin layer chromatographic method and a mass spectroscopic assay method has been developed for the quantification of telmisartan and hydrochlorthiazide combination in human plasma. The internal standards and analytes were extracted from human plasma by solid-phase extraction with HLB Oasis1cc (30mg) catridges. The scanning and optimization for the samples are done using methanol: water (50:50). The samples were chromatographed using reverse phase chromatography with C-18 column of different manufacturers like Ascentis C18 (150×4. 6, 5µ) using the buffer system Acetonitrile: Buffer (80:20%v/v) which consist of 2±0. 1Mm ammonium format at a flow rate of 0. 7ml/min at a column oven temperature 35±10c. The internal standard used was hydrochlorthiazide13c1, d2 and telmisartand3. The extraction techniques include conditioning, loading, washing and elution, drying followed by reconstitution of the dried samples. The volume injected was 10µl with the retention time of 3-4 min for telmisartan, 1-2 min for hydrochlorthiazide and for the internal standards the retention time was 3-4 min for telmisartand3 and 1-2 min for hydrochlorthiazide c13d2. The rinsing solution was Acetonitrile: HPLC grade water in the ratio (50:50). The above developed method was validated using various parameters like selectivity and sensitivity, accuracy and precision, matrix effects, % recovery and various stability studies. The method was proved to be sensitive, accurate, precise and reproducible. The preparation showed high recovery for the quantitative determination of telmisartan and hydrochlorthiazide in human plasma.

A solid-phase extraction method that eliminates matrix effects of complex pulp mill effluents for the analysis of lipophilic wood extractives

2020 ◽  
Vol 35 (4) ◽  
pp. 577-588
Author(s):  
Sebastian España Orozco ◽  
Philipp Zeitlinger ◽  
Karin Fackler ◽  
Robert H. Bischof ◽  
Antje Potthast
Keyword(s):  
Solid Phase Extraction ◽  
Matrix Effects ◽  
Solid Phase ◽  
Internal Standard ◽  
Pulp Mill ◽  
Phase Extraction ◽  
Wood Extractives ◽  
Wood Extractive ◽  
Pulp Mill Effluents ◽  
The Impact

AbstractThe extraction of lipophilic wood extractives from pulp and paper process waters proves to be a challenging task, due to harsh and alternating process and sample conditions. This study has determined the potential use of polymeric sorbents for solid-phase extraction (SPE) and compared to classical silica-based reversed-phase packed columns, with polymeric hydrophilic-lipophilic balanced (HLB) cartridges being the sorbent with the most potential. Recovery functions were obtained with an internal standard mixture representative for the main lipophilic wood extractive groups, which are fatty acids and alcohols, sterols, sterol esters and triglycerides. The impact of pH, sample volume and sample matrix, expressed as TOC and cations, on the retention behavior of lipophilic extractives during SPE of industrial samples were determined with polymeric HLB sorbent. High variations in the composition of pulp mill matrices led to different optimal extraction conditions. Thus, a new SPE protocol was developed, which bypasses matrix interferences and omits the loss of analytes due to sample preparation. The method is applicable to different pulp mill effluents with large discrepancies in pH and sample matrices, resulting in recoveries >90 % with RSD <5 % for all lipophilic wood extractives.

scholarly journals Determination of S-Adenosylmethionine and S-Adenosylhomocysteine in Plasma and Cerebrospinal Fluid by Stable-Isotope Dilution Tandem Mass Spectrometry

2000 ◽  
Vol 46 (10) ◽  
pp. 1650-1656 ◽  
Author(s):  
Eduard A Struys ◽  
Erwin E W Jansen ◽  
Kees de Meer ◽  
Cornelis Jakobs
Keyword(s):  
Mass Spectrometry ◽  
Cerebrospinal Fluid ◽  
Stable Isotope ◽  
Tandem Mass Spectrometry ◽  
Solid Phase ◽  
Extraction Procedure ◽  
Internal Standard ◽  
Tandem Mass ◽  
Analytical Technique

Abstract Background: Available methods for the determination of nanomolar concentrations of S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH) in plasma and cerebrospinal fluid (CSF) are time-consuming. We wished to develop a method for their rapid and simultaneous measurement. Methods: We used tandem mass spectrometry (MS/MS) for the simultaneous determination of SAM and SAH, with stable-isotope-labeled internal standards. The 13C5-SAH internal standard was enzymatically prepared using SAH-hydrolase and [13C5]adenosine. The method comprises a weak anion-exchange solid-phase extraction procedure serving as clean-up step for the deproteinized plasma and CSF samples. After clean-up, samples were injected on a C18 HPLC column, which was connected directly to the tandem mass spectrometer, operating in MS/MS mode. Results: In plasma samples, the intraassay CVs for SAM and SAH were 4.2% and 4.0%, respectively, and the interassay CVs were 7.6% and 5.9%, respectively. In CSF, the intraassay CVs for SAM and SAH were 6.8% and 6.9%, respectively, and the interassay CVs were 4.2% and 5.5%, respectively. Mean recovery of SAM and SAH for both matrices at two concentrations was 93%. Detection limits for SAM and SAH in samples were 7.5 and 2.5 nmol/L, respectively. Concentrations of SAM and SAH in plasma from healthy subjects were within the previously reported ranges. In 10 CSF samples, the mean concentrations (range) were 248 (137–385) nmol/L for SAM and 11.3 (8.9–14.1) nmol/L for SAH. Conclusions: SAM and SAH can be analyzed by MS/MS, taking optimal advantage of the speed and high sensitivity and specificity of this relatively new analytical technique.

Molecularly Imprinted Solid-Phase Extraction for Chlorpyrifos Determination in Water Samples

2010 ◽  
Vol 113-116 ◽  
pp. 947-951 ◽  
Author(s):  
Jun Liu ◽  
Ming Yang ◽  
Lu Feng Huai
Keyword(s):  
Solid Phase Extraction ◽  
Water Samples ◽  
Matrix Effects ◽  
Solid Phase ◽  
Final Analysis ◽  
Sewage Water ◽  
Phase Extraction ◽  
Simple Method ◽  
Molecularly Imprinted ◽  
The Matrix

The determination of chlorpyrifos at low ngL-1 levels in wastewater requires highly selective and sensitive analytical procedures. The removal of matrix components during sample preparation results in significant benefits towards reducing the matrix effects during GC analysis. Therefore this work describes a simple method to enrich and clean up chlorpyrifos from sewage water using molecularly imprinted solid phase extraction (MISPE). Final analysis was performed by gas chromatography. The performance of this method has been evaluated in water samples in terms of recovery, precision, and method quantification limit. Recovery for chlorpyrifos ranged between 99 and 105% with RSD values below 7.9%. The performance of the method was further emphasized by the study of different water samples. In these samples, chlorpyrifos were detected in concentration above method quantification limits ranging from 50 to 3000 ngL-1.

scholarly journals Quantification of α-Thujone and Its Metabolites in Human Urine after Consumption of a Sage Infusion Using Stable Isotope Dilution Assays

Toxins ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 511 ◽  
Author(s):  
Irene Thamm ◽  
Konrad Tiefenbacher ◽  
Michael Rychlik
Keyword(s):  
Detection Limit ◽  
Stable Isotope ◽  
Isotope Dilution ◽  
Human Urine ◽  
Maximum Concentration ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Internal Standard ◽  
Stable Isotope Dilution ◽  
Stable Isotope Dilution Assays

The metabolism of the monoterpene α-thujone was investigated in humans after consumption of sage tea, by analyses of its metabolites 2-hydroxythujone, 4-hydroxythujone, and 7-hydroxythujone in urine. For the quantitation of α-thujone and its metabolites, stable isotope dilution assays were developed. Using d6-α-thujone as internal standard, we quantified α-thujone by solid phase microextraction GC-MS and the hydroxythujones with d6-2-hydroxythujone, d6-4-hydroxythujone, and d6-7-hydroxythujone after glucuronide/sulfate deconjugation by LC-MS/MS in urine. After the consumption of 575.0 µg α-thujone, the 4-hydroxythujone and 7-hydroxythujone were detectable in the urine of the volunteers under study, after liberation from their glucuronides/sulfates. The 2-Hydroxythujone was not present in any of the volunteer samples above its detection limit. α-Thujone was detectable in a low amount, with a maximum concentration of 94 ng/L for the volunteer with the highest dose of 14.3 µg/kg bw.

scholarly journals Simultaneous Quantification of the New Psychoactive Substances 3-FMC, 3-FPM, 4-CEC, and 4-BMC in Human Blood using GC-MS

2019 ◽  
Vol 17 (1) ◽  
pp. 902-911
Author(s):  
Abdulsallam Bakdash
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Human Blood ◽  
Solid Phase ◽  
Internal Standard ◽  
Gas Chromatography Mass Spectrometry ◽  
New Psychoactive Substances ◽  
Selected Ion Monitoring ◽  
Simultaneous Quantification ◽  
Chromatography Mass Spectrometry

AbstractA gas chromatography-mass spectrometry (GC-MS) method for simultaneous quantification of 3-fluoromethcathinone (3-FMC), (±)-3-fluorophenmetrazine (3-FPM), 4-chloroethcathinone (4-CEC) and 4-Bromomethcathinone (4-BMC) in human blood with (±)-methcathinone-D3 as internal standard has been developed and validated. Whole blood samples were treated with 10% trichloroacetic acid for protein precipitation before solid phase extraction. The method was selective, the calibration curves showed linearity for all substances with R2 ranging from 0.991 to 0.998 in the range 5-1.000 ng/mL. Analysis of blank samples showed no-sign of carryover. Precision and accuracy were acceptable with values less than 20% (RSD) and ± 20% (Bias). The limit of quantification (LOQ) for all substances was 5ng/mL. Intra-day and inter-day precision were 2.111.7% and 1.3 -10.2% respectively and accuracy biases were between -10.6-19.6% % (intra-day) and 11-12.1% (inter-day). The extraction efficiencies were 85.4, 82.8, 79.1 and 74.9% for 3-FMC, 3-FPM, 4-CEC and 4-BMC respectively.A robust and reliable simultaneous quantification method using gas chromatography-mass spectrometry in selected ion monitoring mode (GC-MS-SIM) is reported.

Massive intoxication involving unusual high concentration of amitriptyline

2007 ◽  
Vol 26 (8) ◽  
pp. 667-670 ◽  
Author(s):  
Cláudia Margalho ◽  
Mário Barroso ◽  
Eugenia Gallardo ◽  
Paula Monsanto ◽  
Duarte Nuno Vieira
Keyword(s):  
Solid Phase ◽  
Antidepressant Drugs ◽  
Internal Standard ◽  
Tricyclic Antidepressant ◽  
Electron Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
High Concentration ◽  
Selected Ion Monitoring ◽  
Toxic Concentration ◽  
Treatment Of Depression

Amitriptyline is a tricyclic antidepressant widely used in the treatment of depression. Antidepressant drugs are among the most commonly encountered causes of self-poisoning, as illustrated by several published cases in the literature. This investigation reports a case of massive amitriptyline intoxication, involving a 44-year old female found dead in bed. The presence of this tricyclic antidepressant was revealed by a routine screening procedure. The concentration was calculated by gas chromatography/ electron ionization-mass spectrometry in the selected ion monitoring mode after solid-phase extraction using proadifen as internal standard and was in the post-mortem whole blood sample 85.9 μg/mL. This value was much higher than the reported toxic values ever found in the literature, and may therefore have caused the victim's death. Nortriptyline was also detected in the toxic concentration range, as well as therapeutic levels of diazepam and nor-diazepam. Taking into account both the available circumstantial information and toxicological results, it is very likely that death was caused by self-poisoning. Human & Experimental Toxicology (2007) 26, 667—670

scholarly journals Human hepatic N-acetylglutamate content and N-acetylglutamate synthase activity. Determination by stable isotope dilution

1990 ◽  
Vol 271 (2) ◽  
pp. 325-329 ◽  
Author(s):  
M Tuchman ◽  
R A Holzknecht
Keyword(s):  
Stable Isotope ◽  
Isotope Dilution ◽  
Liver Tissue ◽  
Internal Standard ◽  
Tissue Homogenate ◽  
Selected Ion Monitoring ◽  
Human Liver Tissue ◽  
Stable Isotope Dilution ◽  
Acetylglutamate Synthase

N-Acetyl-L-glutamate (N-acetylglutamate) content and N-acetylglutamate synthase activity ranges were established in human liver tissue homogenates by stable isotope dilution. The methods employ N-[methyl-2H3]acetyl[15N]glutamate as internal standard, extraction of N-acetylglutamate by anion-exchange technique and its determination by g.l.c.-mass spectrometry by using selected ion monitoring. Hepatic N-acetylglutamate content in 16 different human livers, normal in structure and function, ranged from 6.8 to 59.7 nmol/g wet wt. (25.0 +/- 13.4 mean +/- S.D.) or from 64.6 to 497.6 nmol/g of protein (223.2 +/- 104.2 mean +/- S.D.). In vitro, N-acetylglutamate synthase activity in liver tissue homogenate ranged from 44.5 to 374.5 (132.0 +/- 90.6 mean +/- S.D.) nmol/min per g wet wt. or from 491.7 to 3416.9 (1159.6 +/- 751.1 mean +/- S.D.) nmol/min per g of protein. No correlation was found between hepatic N-acetylglutamate concentrations and the respective maximal enzymic activities in vitro of N-acetylglutamate synthase. The marked variability in this system among individual livers may reflect its regulatory role in ureagenesis.

scholarly journals HS-SPME-GC-MS Analyses of Volatiles in Plant Populations – Quantitating Compound × Individual Matrix Effects

2018 ◽  
Author(s):  
Elizabeth A. Burzynski-Chang ◽  
Imelda Ryona ◽  
Bruce I. Reisch ◽  
Itay Gonda ◽  
Majid R. Foolad ◽  
...  
Keyword(s):  
Matrix Effects ◽  
Solid Phase ◽  
Internal Standard ◽  
Gas Chromatography Mass Spectrometry ◽  
Plant Populations ◽  
Internal Standards ◽  
Relative Standard ◽  
Breeding Research ◽  
Multiple Analytes ◽  
Two Populations

Headspace solid phase microextraction (HS-SPME) coupled to gas chromatography-mass spectrometry is widely employed for volatile analyses of plants, including mapping populations used in plant breeding research. Studies often employ a single internal surrogate standard, even when multiple analytes are measured, with the assumption that any relative changes in matrix effects among individuals would be similar for all compounds, i.e. matrix effects do not show Compound &times; Individual interactions. We tested this assumption using individuals from two plant populations, an interspecific grape (Vitis spp.) mapping population (n = 140) and a tomato (Solanum spp.) recombinant inbred line (RIL) population (n = 148). Individual plants from the two populations were spiked with a cocktail of internal standards (n = 6, 9, respectively) prior to HS-SPME-GC-MS. Variation in the relative responses of internal standards indicated that Compound &times; Individual interactions exist but were different between the two populations. For the grape population, relative responses among pairs of internal standards varied considerably among individuals, with a maximum of 249% relative standard deviation (RSD) for the pair of [U13C]hexanal and [U13C]hexanol. However, in the tomato population, relative responses of internal standard pairs varied much less, with pairwise RSDs ranged from 8% to 56%. The approach described in this paper could be used to evaluate the suitability of using surrogate standards for HS-SPME-GC-MS studies in other plant populations.

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