scholarly journals Method Development and Validation for Simultaneous Quantification of Microcystin Congeners in Water

2021 ◽  
Author(s):  
Xiaocui Qiao ◽  
Simin Ge ◽  
Chengyou Liu ◽  
Lixin Jiao ◽  
Xue Li ◽  
...  
Keyword(s):  
Formic Acid ◽  
Method Development ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Signal To Noise Ratio ◽  
Internal Standard ◽  
Ultra Performance Liquid Chromatography ◽  
Chaohu Lake ◽  
Online Spe ◽  
Relative Standard

Abstract Background: Microcystins, as secondary metabolites of cyanobacteria, are hepatotoxic to humans through the ingestion of cyanobacteria-contaminated water. Microcystins with diverse congeners in water can be precisely quantified using online solid phase extraction-ultra performance liquid chromatography-tandem mass spectrometry (online-SPE UPLC-MS/MS). A method was developed and validated to simultaneously quantify eight microcystin congeners in water using online-SPE UPLC-MS/MS.Results: The method achieved the highest efficiency and sensitivity by selecting acetonitrile with 0.1% formic acid and water with 0.1% formic acid as the best mobile phase conditions. Linearity, accuracy, and precision were validated on matrix-mixed water with the leucine enkephalin internal standard. The limit of detection calculated using the signal-to-noise ratio of 3 passed the surface water daily inspection for microcystins. Except for the lower recovery of individual substances at individual concentrations, the recoveries of the remaining microcystin congeners ranged from 70 to 130%, and the relative standard deviation was less than 10%.Conclusion: The method was used to analyze microcystins in 12 water samples collected from Chaohu Lake. The sum of all microcystin congeners ranged from 101 to 585 ng L-1 in water (<WHO drinking water safe limit of 1 μg L-1 for microcystin-LR).

scholarly journals Method development and validation for simultaneous quantification of microcystin congeners in water

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Xiaocui Qiao ◽  
Simin Ge ◽  
Chengyou Liu ◽  
Lixin Jiao ◽  
Xue Li ◽  
...  
Keyword(s):  
Formic Acid ◽  
Method Development ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Internal Standard ◽  
World Health ◽  
Chaohu Lake ◽  
High Concentration ◽  
Online Spe ◽  
Relative Standard

Abstract Background Microcystins (MCs) are secondary metabolites of cyanobacteria that are hepatotoxic to humans through the ingestion of cyanobacteria-contaminated water and accidental inhalation from lake activities. MCs with diverse congeners in water can be precisely quantified using online solid-phase extraction-ultra performance liquid chromatography coupled with tandem mass spectrometry (online-SPE UPLC–MS/MS). A method was developed and validated to simultaneously quantify eight different MCs (microcystin-RR, -LR, -YR, -WR, -LA, -LF, -LY, and -LW) in water using online-SPE UPLC–MS/MS. Results The method achieved the highest efficiency and sensitivity by selecting acetonitrile with 0.1% formic acid and water with 0.1% formic acid as the best mobile phase conditions. The linearity, accuracy, and precision were validated using matrix-mixed water with a leucine enkephalin internal standard. The limit of detection (LOD) was calculated using the signal-to-noise ratio of three passes of the daily water-surface inspection for MCs. This method showed both high sensitivity and high resolution for the separation of eight MC congeners with LODs ranging from 0.020 to 0.371 ng L–1 and limits of quantitation ranging from 0.066 to 1.24 ng L–1. The detection time was reduced to 11 min. Except for MC-RR (58.8% recovery at high concentration) and MC-WR (45.1% and 40.9% recoveries at medium and high concentrations, respectively), the recoveries of the other MCs ranged from 70 to 135%, and the relative standard deviation was less than 10%. Conclusion Eight different MCs in 12 water samples collected from Chaohu Lake, China, were analyzed. The sum of all MC congeners was calculated to range from 101 to 585 ng L–1 (less than the World Health Organization’s safe drinking water limit of 1 μg L–1 for MC-LR).

Development of a solid-phase extraction – spectrofluorimetric method for trace glutathione determination

2011 ◽  
Vol 89 (4) ◽  
pp. 517-523 ◽  
Author(s):  
Ke-Jing Huang ◽  
Cong-Hui Han ◽  
Ying-Ying Wu ◽  
Chao-Qun Han ◽  
De-Jun Niu ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Signal To Noise Ratio ◽  
Calibration Graph ◽  
Extraction Column ◽  
Phase Extraction ◽  
Selective Reaction ◽  
Spectrofluorimetric Method ◽  
Relative Standard

A simple and efficient solid-phase extraction – spectrofluorimetric method has been developed to determine glutathione (GSH). Fluorescent probe N-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-yl)methyl)iodoacetamide (BODIPY Fl-C1-IA) was used as the derivatization reagent. The procedure was based on a BODIPY Fl-C1-IA selective reaction with GSH to form the highly fluorescent product BODIPY Fl-C1-IA–GSH, using a solid-phase extraction column and spectrofluorimetric determination. The variables affecting analytical performance were studied and optimized. The calibration graph using the preconcentration system for GSH was linear over the range of 1–200 nmol/L with a limit of detection of 0.05 nmol/L (signal-to-noise ratio = 3). The relative standard deviation for six replicate determinations of GSH at the 100 nmol/L concentration level was 3.9%. The method was applied to water samples and average recoveries between 87.5% and 111.5% were obtained for spiked samples.

Quantitation of Sulfamethazine in Pork Tissue by Thin-Layer Chromatography

1993 ◽  
Vol 76 (2) ◽  
pp. 335-341 ◽  
Author(s):  
Joseph Unruh ◽  
Daniel P Schwartz ◽  
Robert A Barford
Keyword(s):  
Thin Layer ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Signal To Noise Ratio ◽  
Internal Standard ◽  
Signal To Noise ◽  
Thin Layer Chromatographic Plate ◽  
Average Accuracy ◽  
Chromatographic Plate ◽  
Layer Chromatography

Abstract Our earlier method to detect and quantitate sulfamethazine (SMZ) in milk at the 10 ppb level was modified to quantitate SMZ in pork tissue. Sulfabromomethazine (SBZ) is added to the tissue as an internal standard. SMZ and SBZ are extracted from the tissue into water as the supernatant of a centrifuged, aqueous homogenate and are cleaned up and concentrated by a series of solid-phase extractions. The sulfonamide-containing eluate is then separated on a silica gel thin-layer chromatographic plate. SBZ and SMZ are derivatized with fluorescamine, and their fluorescence is quantitated with a scanning densitometer. The limit of detection was estimated at 0.25 ppb (signal-to-noise ratio, 3:1). The average accuracy over the analysis range (0.54-21.8 ppb [μg/kg]) was 95.6% (standard deviation = 29.4%, n = 54).

scholarly journals METHOD DEVELOPMENT AND VALIDATION FOR ANALYSIS OF DEOXYARBUTININ ANHYDROUS EMULSION SYSTEM USING HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY

2019 ◽  
pp. 172-175 ◽  
Author(s):  
MUCHTARIDI MUCHTARIDI ◽  
IDA MUSFIROH ◽  
AHMAD FAUZI
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Analytical Method ◽  
High Performance ◽  
Method Development ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Emulsion System ◽  
Relative Standard ◽  
Limit Of Quantitation

Objective: The aim of this study is to develop a simple, precise and accurate analytical method of deoxyarbutin in anhydrous emulsion system preparation. Methods: The analysis was conducted using high-performance liquid chromatography (HPLC). Chromatographic analysis was carried out using a reversed phase-C18 column. The mobile consists of two phases methanol and water (60: 40 v/v) at a flow rate of 1.0 ml/min. The determinations were performed using UV detector set at 225 nm. All validation procedures were added with hydroquinone as an internal standard. Results: The method showed coefficient correlation is 0.9978, relative standard deviation (RSD) smaller than 2%, Limit of Detection (LOD) and Limit of Quantitation (LOQ) are 0.599 µg/ml and 1.817 µg/ml respectively. The total amount deoxyarbutin in anhydrous emulsion preparation is 1.964+0.02 % with 98% recovery percentage. Conclusion: The developed HPLC analytical method meets the validation criteria made by International Conference on Harmonisation (ICH).

scholarly journals Development of EPA Method 535 for the Determination of Chloroacetanilide and Other Acetamide Herbicide Degradates in DrinkingWater by Solid-Phase Extraction and Liquid Chromatography/TandemMass Spectrometry

2006 ◽  
Vol 89 (1) ◽  
pp. 201-209 ◽  
Author(s):  
Jody A Shoemaker ◽  
Margarita V Bassett
Keyword(s):  
Drinking Water ◽  
Liquid Chromatography ◽  
Solid Phase Extraction ◽  
Environmental Protection Agency ◽  
Method Development ◽  
Solid Phase ◽  
Degradation Products ◽  
Internal Standard ◽  
Phase Extraction ◽  
Relative Standard

Abstract U.S. Environmental Protection Agency (EPA) Method 535 has been developed in order to provide a method for the analysis of Alachlor ESA and other acetanilide degradation products, which are listed on EPA's 1998 Drinking Water Contaminant Candidate List. Method 535 uses solid-phase extraction with a nonporous graphitized carbon sorbent to extract the ethane sulfonic acid (ESA) and oxanilic acid degradates of propachlor, flufenacet, dimethenamid, alachlor, acetochlor, and metolachlor from finished drinking water matrixes. Separation and quantitation of the target analytes are achieved with liquid chromatography/tandem mass spectrometry. Dimethachlor ESA and butachlor ESA were chosen during the method development as the surrogate and internal standard. Drinking water samples were dechlorinated with ammonium chloride without adversely affecting the analyte recoveries. Typical mean recoveries of 92116% in deionized water and 89116% in ground water were observed with relative standard deviations of &lt;5%.

scholarly journals Determination of Trace Zearalenone and Its Metabolites in Human Serum by a High-Throughput UPLC-MS/MS Analysis

2019 ◽  
Vol 9 (4) ◽  
pp. 741 ◽  
Author(s):  
Danlei Sun ◽  
Chenglong Li ◽  
Shuang Zhou ◽  
Yunfeng Zhao ◽  
Yun Gong ◽  
...  
Keyword(s):  
Human Serum ◽  
High Throughput ◽  
Solid Phase ◽  
Internal Standard ◽  
Ultra Performance Liquid Chromatography ◽  
Enzyme Hydrolysis ◽  
Serum Samples ◽  
Relative Standard ◽  
Before And After

This paper described an improved method for high-throughput and sensitive determination of zearalenone and its five metabolites (zearalanone, α-zearalenol, β-zearalenol, α-zearalanol and β-zearalanol) in human serum. Serum samples were measured both before and after enzyme hydrolysis to assess the free and total amount of each compound by ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) in multi reaction monitoring (MRM) mode following off-line 96-well μElution solid-phase extraction (SPE). All the analytes were completely separated on a C18 column within 6 min. It enabled multi-sample preparation at the same time eliminating tedious evaporation and reconstitution steps, allowing 96 (one plate) samples to be processed and analyzed within 24 h. Using an isotope labelled internal standard (13C-ZEN), high recoveries were achieved for all the compounds in the range 91.6%–119.5%, with intra-day and inter-day relative standard deviations (RSDs) of less than 8%. The limits of detection (LOD) and the limits of quantification (LOQ) were 0.02–0.06 ng mL−1 (0.6–2 fmol) and 0.1–0.2 ng mL−1 (3–6 fmol), respectively, demonstrating a notable enhancement in sensitivity compared to the existing methods. The validated method was applied to the analysis of paired urine and serum samples collected from 125 healthy individuals in Henan Province, locating in the middle area of China. ZEN metabolites in human serum were significantly lower than those in urine. Only one serum sample was positive for ZEN after enzyme digestion, whereas at least one of ZEN biomarkers was detected in 75.2% of the paired urine samples. Some comparison and discussion were also included in this paper.

A Novel Electrochemiluminescence Sensor for Sensitive Determination of Carbaryl Based on Solid Phase Microextraction at NH2–Graphene–Nafion Modified Electrode

2015 ◽  
Vol 68 (5) ◽  
pp. 793 ◽  
Author(s):  
Sui Wang ◽  
Shasha Lv ◽  
Wenwen Wu ◽  
Zhiyong Guo
Keyword(s):  
Solid Phase Microextraction ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Signal To Noise Ratio ◽  
Initial Response ◽  
X Ray Diffraction ◽  
Relative Standard ◽  
Sensitive Determination ◽  
Response Current

Sensitive electrochemiluminescence (ECL) detection and solid phase microextraction (SPME) using a NH2–graphene–Nafion modified glassy carbon electrode was developed for carbaryl. The NH2–graphene was synthesised and characterised by Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. The main parameters that affect the extraction efficiencies, such as the buffer and sample pH, and extraction time were investigated and optimised. The introduction of NH2–graphene into Nafion improves the conductivity of the film because of its electrical conductivity. The electrode enables the determination of carbaryl in the range from 5 × 10–4 to 10 μg mL–1, and the limit of detection was 2 × 10–4 μg mL–1 at a signal-to-noise ratio of 3. The ECL intensity retained 97 % of its initial response current after storage for 10 days, indicating a good storage stability of the sensor. The relative standard deviations (RSDs) of intra-assay and inter-assay were found to be 3.5 and 5.3 %, respectively, indicating an acceptable reproducibility. Furthermore, the ECL sensor was successfully applied to the selective and sensitive quantitative determination of carbaryl in river samples, the recoveries of carbaryl ranged from 99.0 to 108.0 %, and the RSDs were less than 5.0 %, which shows good reproducibility and high precision of analysis.

Rapid Determination of Total Cholesterol in Homogenized Milk

1989 ◽  
Vol 72 (3) ◽  
pp. 421-424 ◽  
Author(s):  
Ida C Tsui
Keyword(s):  
Total Cholesterol ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Rapid Determination ◽  
Internal Standard ◽  
Gas Chromatograph ◽  
Relative Standard ◽  
Aoac Method ◽  
Normal Work

Abstract A rapid method that is amenable to automation has been developed for the determination of total cholesterol in homogenized milk. The milk sample is saponified in ethanolic KOH in the presence of an internal standard, cholestane. Cholesterol and the internal standard are then isolated by solid-phase extraction on a nonpolar adsorbent and eluted with organic solvent. The evaporated extract is derivatized and analyzed by capillary gas chromatography. Average recovery of cholesterol acetate added to milk prior to saponification was 95%. The average relative standard deviation for repeated analyses was 2%. The limit of detection for this method is 2 mg/100 g. Twenty samples can be analyzed by one analyst in a normal work day if the gas chromatograph is equipped with an autosampler. This method has been compared with a modified AOAC method for the determination of total cholesterol. At a confidence level of 95%, no difference was observed between the 2 methods.

scholarly journals Method Development for Selected Bisphenols Analysis in Sweetened Condensed Milk from a Can and Breast Milk Samples by HPLC–DAD and HPLC-QqQ-MS: Comparison of Sorbents (Z-SEP, Z-SEP Plus, PSA, C18, Chitin and EMR-Lipid) for Clean-Up of QuEChERS Extract

Molecules ◽  
2019 ◽  
Vol 24 (11) ◽  
pp. 2093 ◽  
Author(s):  
Tomasz Tuzimski ◽  
Szymon Szubartowski
Keyword(s):  
Breast Milk ◽  
Secondary Amine ◽  
Method Development ◽  
Solid Phase ◽  
Internal Standard ◽  
Matrix Composition ◽  
Milk Samples ◽  
Relative Standard ◽  
Primary Secondary Amine

Background: Identification and quantitative determination of analytes released from the packaging material is undoubtedly a difficult and tricky task, requiring the chemical analyst to develop an individual approach to obtain reliable analytical information. Unfortunately, it is still challenging for scientists to determine bisphenols at trace or even ultra-trace levels in samples characterized by a very complex, and often variable, matrix composition. Objective: Optimization and application of QuEChERS/d-SPE coupled with HPLC-DAD (and LC-QqQ-MS) method for the simultaneous determination of bisphenols (A, S, F, B, BADGE and derivatives) in milk samples from a can and breast milk samples have been performed. Methods: Concerning the analysis of unconjugated analytes, after the thawing and shaking the sample (5 mL breast milk or 10 mL milk samples from a can), it was transferred into a 50 mL polypropylene centrifuge tube. For the analysis of the total amount of analytes, prior to the extraction with acetonitrile, a deconjugation step was implemented in a tube by adding to sample, the an Isotopically Labelled Internal Standard (IS) solution (50 ng/mL) and 1 mL of the enzymatic solution with the β-Glucuronidase (3500 U/mL). The mix was homogenized and incubated for 16–18 h at 37 °C. Next, 10 mL of acetonitrile, and a QuEChERS salt packet (4 g anhydrous MgSO4, 1 g NaCl) were added. After shaking and centrifugation, the total acetonitrile layer was isolated in a polypropylene tube evaporate to dryness, and reconstitute in 1.2 mL acetonitrile. During d-SPE step the extract was transferred into a 15 mL polypropylene tube with Z-Sep and primary secondary amine (PSA). Next, shake the tube, store in fridge, and centrifuge for 15 min. The acetonitrile supernatant was obtained with a pipette and evaporated to dryness. Mixture MeOH: water (20:80, v/v) were added to the dry residue and the extract was reconstitute in 200 μL and analyzed by HPLC-DAD and HPLC–QqQ-MS equipment. Conclusion: Six different salts during d-SPE step were evaluated such as: zirconium dioxide-based sorbent (Z-Sep, Z-Sep Plus), primary secondary amine (PSA), octadecyl (C18), EMR-Lipid, Chitin and also their mixtures. Negligible matrix interference was observed for most of the analytes due to application of Z-Sep and PSA in dispersive-solid phase extraction clean-up step. Extraction of target analytes was performed using QuEChERS/d-SPE cleanup, and presents good performance for selected analytes with recoveries in the range of 15–103% and relative standard deviations (RSD) less than 10% in breast milk samples.

A Simple Vortex-Assisted Magnetic Dispersive Solid Phase Microextraction System for Preconcentration and Separation of Triazine Herbicides from Environmental Water and Vegetable Samples Using Fe3O4@MIL-100(Fe) Sorbent

2018 ◽  
Vol 101 (5) ◽  
pp. 1639-1646 ◽  
Author(s):  
Atefe Nasrollahpour ◽  
Seyyed Ershad Moradi
Keyword(s):  
Solid Phase Microextraction ◽  
High Performance ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Signal To Noise Ratio ◽  
Correlation Coefficients ◽  
Environmental Water ◽  
Triazine Herbicides ◽  
Vegetable Samples ◽  
Relative Standard

Abstract A vortex-assisted magnetic dispersive solid phase microextraction coupled with high-performance liquid chromatography has been developed for the extraction and determination of triazine herbicides by using magnetic metal organic frameworks [Fe3O4@MIL-100(Fe)] in environmental water and vegetable samples. The Fe3O4@MIL-100(Fe) composite has been characterized by using X-ray diffraction spectroscopy, tunneling electron microscopy, thermogravimetric measurement, and Brunauer-Emmett-Teller analysis. The method is based on the sorption of triazine herbicides on Fe3O4@MIL-100(Fe) because of the complex formation between iron oxide nanoparticles and triazine herbicides beside π-π interactions between organic parts of Fe3O4@MIL-100(Fe) and triazine herbicides. The experimental parameters for the preconcentration of triazine herbicides, such as the type and volume of the eluent, pH, time of the sorption and desorption, and the amount of the sorbent, were optimized. Under the optimized conditions, the method was linear over the concentration range of 0.0061 to 70 ng/mL for each triazine herbicide, and the correlation coefficients ranged from 0.9988 to 0.9997. The limit of detection of the method at a signal-to-noise ratio of 3 was 2.0 to 5.3 ng/mL. The relative standard deviations for inter- and intraday assays were in the range of 5.8 to 10.2% and 3.8 to 6.3%, respectively.

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