scholarly journals Studies on the Stability of Acrylamide in Food During Storage

2005 ◽  
Vol 88 (1) ◽  
pp. 268-273 ◽  
Author(s):  
Katrin Hoenicke ◽  
Robert Gatermann
Keyword(s):  
Milk Powder ◽  
Internal Standard ◽  
Food Samples ◽  
Reaction Products ◽  
Before And After ◽  
Raw Sugar ◽  
Liquid Chromatography Tandem Mass ◽  
Sh Group ◽  
The Stability ◽  
Soluble Coffee

Abstract Acrylamide levels in a variety of food samples were analyzed before and after 3 months of storage at 10°–12°C. The analysis was performed by liquid chromatography tandem mass spectrometry (LC/MS/MS) using deuterium-labeled acrylamide as internal standard. Acrylamide was stable in most matrixes (cookies, cornflakes, crispbread, raw sugar, potato crisps, peanuts) over time. However, slight decreases were determined for dietary biscuits (83–89%) and for licorice confection (82%). For coffee and cacao powder, a significant decrease occurred during storage for 3 or 6 months, respectively. Acrylamide concentrations dropped from 305 to 210 μg/kg in coffee and from 265 to 180 μg/kg in cacao powder. On the contrary, acrylamide remained stable in soluble coffee as well as in coffee substitutes. Reactions of acrylamide with SH group-containing substances were assumed as the cause for acrylamide degradation in coffee and cacao. Spiking experiments with acrylamide revealed that acrylamide concentrations remained stable in baby food, cola, and beer; however, recovery levels dropped in milk powder (71%), sulfurized apricot (53%), and cacao powder (17%). These observations suggest that variations in the acrylamide content of food, especially in coffee and cacao, can vary depending on the storage time because special food constituents and/or reaction products can affect the levels.

Short-term stability of free metanephrines in plasma and whole blood

2020 ◽  
Vol 58 (5) ◽  
pp. 753-757 ◽  
Author(s):  
Elisa Danese ◽  
Martina Montagnana ◽  
Claudio Brentegani ◽  
Giuseppe Lippi
Keyword(s):  
Whole Blood ◽  
Repeated Measures ◽  
Sample Collection ◽  
Short Term ◽  
Total Change ◽  
Term Stability ◽  
Before And After ◽  
Liquid Chromatography Tandem Mass ◽  
The Mean ◽  
The Stability

AbstractBackgroundAnalysis of plasma metanephrine (MN) and normetanephrine (NMN) with liquid chromatography tandem mass spectrometry (LC-MS/MS) is the gold standard for the screening of pheochromocytomas and paragangliomas (PPGLs). As scarce information is available on the stability of MNs in diagnostic samples, this study was aimed at analyzing the short-term stability of plasma free MNs in whole blood and plasma, using LC-MS/MS.MethodsThe stability of plasma MNs was evaluated after sample collection at 1, 2 and 3 h in whole blood, and at 2, 4 and 6 h in centrifuged samples. Both studies were performed while maintaining the samples at room temperature (RT) and at 4 °C. The ClinMass Complete Kit (Recipe, Munchen, Germany) was used for measuring MNs with LC-MS/MS (Nexera X2 UHPLC-4500MD Sciex). Differences from the baseline (T0) were assessed using repeated measures one-way ANOVA, Students’ paired t-test and a comparison of the mean percentage changes with the total change limit (TCL).ResultsStatistically significant differences from T0 were found for both MNs (p < 0.001) in whole blood stored at RT, and for NMN (p = 0.028) but not MN (p = 0.220) at 4 °C. The mean difference exceeded the TCL after 1 h and 3 h at RT for MN, and after 1 h at RT for NMN. Statistically significant differences from T0 were only observed in the plasma samples for NMN at RT (p = 0.012), but the variation was within the TCL.ConclusionsMN and NMN displayed different patterns of stability before and after centrifugation. Even short-time storage at RT in whole blood should hence be avoided.

scholarly journals Stability of Extemporaneously Prepared Lansoprazole Suspension at Two Temperatures

2013 ◽  
Vol 18 (2) ◽  
pp. 122-127 ◽  
Author(s):  
Jordan T. Morrison ◽  
Ralph A. Lugo ◽  
Jim C. Thigpen ◽  
Stacy D. Brown
Keyword(s):  
Sodium Bicarbonate ◽  
Room Temperature ◽  
Internal Standard ◽  
Storage Condition ◽  
Significant Difference ◽  
Expiration Time ◽  
Liquid Chromatography Tandem Mass ◽  
Two Temperatures ◽  
The Stability ◽  
Oral Sodium

OBJECTIVE The purpose of this study was to examine the stability of a generic lansoprazole product in a 3 mg/mL sodium bicarbonate suspension under room temperature and refrigerated conditions. METHODS Lansoprazole suspensions (3 mg/mL) were prepared in triplicate using an 8.4% sodium bicarbonate vehicle for each storage condition (room temperature and refrigerated). During 1 month, samples from each replicate were periodically removed and analyzed for lansoprazole concentration by liquid chromatography–tandem mass spectrometry (LC-MS/MS). Each sample was spiked with 10 mg/L omeprazole to serve as the internal standard. A positive electrospray LC-MS/MS method was validated over the calibration range of 5 to 25 mg/L using Food and Drug Administration Guidance. The identities of the analyte and internal standard in the samples were verified by monitoring the MS/MS transitions of m/z 370 to m/z 252 and m/z 346 to m/z 198 for lansoprazole and omeprazole, respectively. Additionally, the pH of the suspensions was monitored throughout the study. RESULTS The stability of lansoprazole in the oral sodium bicarbonate suspension under refrigeration is compromised prior to what has been previously reported in the literature. Samples kept at room temperature lost &gt;10% of the lansoprazole after 48 hours compared with the refrigerated samples, which maintained integrity up to 7 days. No statistically significant difference was found between the pH of the room temperature and refrigerated suspension samples, indicating that this factor is not the cause for the differences in stability at these two conditions. CONCLUSIONS This study suggests that the extemporaneously compounded lansoprazole oral suspension prepared in 8.4% sodium bicarbonate should not be stored in plastic oral syringes longer than 48 hours at room temperature and no longer than 7 days when refrigerated. These data indicate an expiration time earlier than that previously reported for the refrigerated product (14 days).

scholarly journals THE EFFECT OF ANTICOAGULANT TYPES ON THE IN VITRO ANALYSIS OF CLOPIDOGREL IN HUMAN PLASMA USING LIQUID CHROMATOGRAPHY TANDEM-MASS SPECTROMETRY

2018 ◽  
Vol 10 (1) ◽  
pp. 392
Author(s):  
Yahdiana Harahap ◽  
Anisa Maulidina ◽  
Delly Ramadon
Keyword(s):  
Liquid Chromatography ◽  
Internal Standard ◽  
Linear Calibration ◽  
Column Temperature ◽  
Heparin Plasma ◽  
Liquid Chromatography Tandem Mass ◽  
Edta Plasma ◽  
The Stability ◽  
Vitro Analysis

Objective: The aim of this study was to optimize and validate a plasma clopidogrel analysis method using liquid chromatography tandem-massspectrometry.Methods: Plasma samples were analyzed using a BEH C18 column (1.7 μm; 100 mm×2.1 mm), the mobile phase was 0.1% formic acid in acetonitrile(30:70, v/v). The flow rate was 0.2 mL/min, with a column temperature set to 35°C, an injection volume of 5 μL, an analysis time of 4 min, andirbesartan as the internal standard. Aliquots were obtained by liquid-liquid extraction using ammonium acetate and diethyl ether. The stability andpeak area ratio of the respective plasma area responses were evaluated using ANOVA.Results: No significant differences (p>0.05) were observed between anticoagulants regarding analyte stability. However, the peak area ratioshowed significant differences (p<0.05) between the anticoagulants. The accuracy and precision of the analysis with citrate, heparin, andethylenediaminetetraacetic acid (EDTA) plasma met the quality requirements, and a linear calibration curve was created with concentrations rangingfrom 0.02 to 5.0 ng/mL.Conclusion: The results showed that improved analysis of clopidogrel was achieved using citrate or heparin plasma compared with EDTA plasma.

scholarly journals A UPLC-MS/MS METHOD DEVELOPMENT AND VALIDATION FOR THE ESTIMATION OF POMALIDOMIDE FROM HUMAN PLASMA

2016 ◽  
Vol 9 (1) ◽  
pp. 37 ◽  
Author(s):  
D. Atul Vasanth ◽  
B. Rajkamal
Keyword(s):  
Formic Acid ◽  
Chromatographic Separation ◽  
Method Development ◽  
Internal Standard ◽  
Pharmacokinetic Studies ◽  
Solution Stability ◽  
Tandem Mass ◽  
Stability Studies ◽  
Liquid Chromatography Tandem Mass ◽  
The Stability

Objective: The present work aimed to develop a simple, rapid, specific and precise liquid chromatography-tandem mass spectrophotometric (LC–MS/MS) validated method for quantification of pomalidomide and internal standard (ISTD) Fluconazole in human plasma.Methods: 50 µl of 0.1% formic acid was added to plasma samples prior to liquid-liquid extraction (LLE) using 2.5 ml of ethyl acetate. Chromatographic separation was achieved on Xterra, RP18, 5 µ (50 x 4.6 mm) column using a mixture of 0.1% (v/v) formic acid in water to methanol at a ratio of 12:88, v/v as the mobile phase. The flow rate was 0.50 ml/min. The LC eluent was split, and approximately 0.1 ml/min was introduced into Tandem mass spectrometer using turbo Ion Spray interface at 325 °C. Quantitation was performed by transitions of m/z 260.1 precursor ion to the m/z 148.8 for pomalidomide and m/z 307.1/238.0 for fluconazole.Results: The concentrations of nine working standards showed linearity between 9.998 to 1009.650 ng/ml (r2 ≥ 0.9968). Chromatographic separation was achieved within 2 min. The average extraction recoveries of three quality control concentrations were 53.86% for pomalidomide and were within the acceptance limits. The coefficient of variation was ≤15% for intra-and inter-batch assays. The %CV of ruggedness ranges 1.32 to 4.03. The % stability of short term and long term stock solution stability studies was found to be 99.01% and 98.49% respectively.Conclusion: The results obtained for specificity, linearity, accuracy, precision, ruggedness and stability studies were within limits. Thus the validated economical method was applied for pharmacokinetic studies of pomalidomide.

scholarly journals Multiple Mycotoxins Determination in Food by LC-MS/MS: An International Collaborative Study

Toxins ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 658 ◽  
Author(s):  
Thomas Bessaire ◽  
Claudia Mujahid ◽  
Pascal Mottier ◽  
Aurélien Desmarchelier
Keyword(s):  
Collaborative Study ◽  
Milk Powder ◽  
Food Samples ◽  
Relative Standard ◽  
Liquid Chromatography Tandem Mass ◽  
Mycotoxin Analysis ◽  
Repeatability And Reproducibility ◽  
Iso 5725 ◽  
Infants And Young Children

An intercollaborative study was organized to evaluate the performance characteristics of a liquid chromatography tandem mass spectrometry procedure for the simultaneous determination of 12 mycotoxins in food, which were ochratoxin A, aflatoxins B1, B2, G1, G2, and M1, deoxynivalenol, zearalenone, fumonisins B1 and B2, and T-2 and HT-2 toxins. The method combined the simplicity of the QuEChERS (Quick, Easy, Cheap, Efficient, Rugged and Safe) approach with the efficiency of immunoaffinity column cleanup (the step used to enhance sensitivity and sample cleanup for some matrices only). Twenty-three entities were enrolled and were European reference laboratories for mycotoxin analysis, U.S. and European service laboratories, and Nestlé laboratories. Each participant analyzed 28 incurred and/or spiked blind samples composed of spices, nuts, milk powder, dried fruits, cereals, and baby food using the protocol given. Method performances were assessed according to ISO 5725-2. Relative standard deviations of repeatability and reproducibility and trueness values for each of the 115 mycotoxin/sample combinations ranged from 5% to 23%, 7% to 26%, and 85% to 129%, respectively, in line with requirements defined in EC 401/2006. The overall set of data gathered demonstrated that the method offered a unique platform to ensure compliance with EC 1881/2006 and EC 165/2013 regulations setting maximum limits for mycotoxins in food samples, even at low regulated levels for foods intended for infants and young children. The method was applicable regardless of the food, the regulated mycotoxin, and the concentration level, and thus is an excellent candidate for future standardization.

scholarly journals A Dilute and Shoot Strategy for Determining Alternaria Toxins in Tomato-Based Samples and in Different Flours Using LC-IDMS Separation

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1017
Author(s):  
Ádám Tölgyesi ◽  
Tamás Farkas ◽  
Mária Bálint ◽  
Thomas J. McDonald ◽  
Virender K. Sharma
Keyword(s):  
Matrix Effects ◽  
Internal Standard ◽  
High Sensitivity ◽  
Food Samples ◽  
Standard Samples ◽  
Limit Of Quantification ◽  
Enhanced Sensitivity ◽  
Alternaria Toxins ◽  
Sample Extraction ◽  
Liquid Chromatography Tandem Mass

Alternaria toxins are emerging mycotoxins whose regulation and standardization are in progress by the European Commission and the European Committee for Standardization. This paper describes a dilute and shoot approach to determine five Alternaria toxins in selected food samples using liquid chromatography–tandem mass spectrometry (LC-MS/MS). The strategy involves sample extraction with acidified aqueous methanol, followed by a solvent change accomplished via sample evaporation and reconstitution. The quantification is based on isotope dilution, applying all corresponding isotopically labeled internal standards to compensate possible matrix effects of the analysis. The main advantages of the present method over other existing methods includes simple and effective sample preparation, as well as detection with high sensitivity. The five-fold sample dilution can decrease matrix effects, which were evaluated with both external and internal standard methods. The results demonstrated a limit of quantification lower than 1.0 µg/kg for all five analytes for the first time. The newly presented method showed acceptable accuracy (52.7–111%) when analyzing naturally contaminated and spiked standard samples at the described levels. The method was validated for tomato-based and flour samples (wheat, rye, and maize). The absolute recovery ranged from 66.7% to 91.6% (RSD < 10%). The developed method could be an alternative approach for those laboratories that exclude sample cleanup and pre-concentration of state-of-the-art instruments with enhanced sensitivity.

The stability of dislocation networks under various oxygen-doping conditions in superconducting Bi2Sr2CaCu2Oy single crystals and their influence on the flux pinning properties

1994 ◽  
Vol 52 ◽  
pp. 802-803
Author(s):  
Y. Feng ◽  
X. Y. Cai ◽  
R. J. Kelley ◽  
D. C. Larbalestier
Keyword(s):  
Single Crystals ◽  
Oxygen Content ◽  
Basal Plane ◽  
Flux Pinning ◽  
Pinning Centers ◽  
Before And After ◽  
Anomalous Peak ◽  
Basal Plane Dislocation ◽  
The Stability ◽  
Further Development

The issue of strong flux pinning is crucial to the further development of high critical current density Bi-Sr-Ca-Cu-O (BSCCO) superconductors in conductor-like applications, yet the pinning mechanisms are still much debated. Anomalous peaks in the M-H (magnetization vs. magnetic field) loops are commonly observed in Bi2Sr2CaCu2Oy (Bi-2212) single crystals. Oxygen vacancies may be effective flux pinning centers in BSCCO, as has been found in YBCO. However, it has also been proposed that basal-plane dislocation networks also act as effective pinning centers. Yang et al. proposed that the characteristic scale of the basal-plane dislocation networksmay strongly depend on oxygen content and the anomalous peak in the M-H loop at ˜20-30K may be due tothe flux pinning of decoupled two-dimensional pancake vortices by the dislocation networks. In light of this, we have performed an insitu observation on the dislocation networks precisely at the same region before and after annealing in air, vacuumand oxygen, in order to verify whether the dislocation networks change with varying oxygen content Inall cases, we have not found any noticeable changes in dislocation structure, regardless of the drastic changes in Tc and the anomalous magnetization. Therefore, it does not appear that the anomalous peak in the M-H loops is controlled by the basal-plane dislocation networks.

Sorbitol enhances the physicochemical stability of B12 vitamers

2020 ◽  
Vol 90 (5-6) ◽  
pp. 439-447 ◽  
Author(s):  
Andrew Hadinata Lie ◽  
Maria V Chandra-Hioe ◽  
Jayashree Arcot
Keyword(s):  
Ascorbic Acid ◽  
Uv Light ◽  
Heat Exposure ◽  
Water Soluble ◽  
Uv Exposure ◽  
Physicochemical Stability ◽  
Before And After ◽  
The Stability

Abstract. The stability of B12 vitamers is affected by interaction with other water-soluble vitamins, UV light, heat, and pH. This study compared the degradation losses in cyanocobalamin, hydroxocobalamin and methylcobalamin due to the physicochemical exposure before and after the addition of sorbitol. The degradation losses of cyanocobalamin in the presence of increasing concentrations of thiamin and niacin ranged between 6%-13% and added sorbitol significantly prevented the loss of cyanocobalamin (p<0.05). Hydroxocobalamin and methylcobalamin exhibited degradation losses ranging from 24%–26% and 48%–76%, respectively; added sorbitol significantly minimised the loss to 10% and 20%, respectively (p < 0.05). Methylcobalamin was the most susceptible to degradation when co-existing with ascorbic acid, followed by hydroxocobalamin and cyanocobalamin. The presence of ascorbic acid caused the greatest degradation loss in methylcobalamin (70%-76%), which was minimised to 16% with added sorbitol (p < 0.05). Heat exposure (100 °C, 60 minutes) caused a greater loss of cyanocobalamin (38%) than UV exposure (4%). However, degradation losses in hydroxocobalamin and methylcobalamin due to UV and heat exposures were comparable (>30%). At pH 3, methylcobalamin was the most unstable showing 79% degradation loss, which was down to 12% after sorbitol was added (p < 0.05). The losses of cyanocobalamin at pH 3 and pH 9 (~15%) were prevented by adding sorbitol. Addition of sorbitol to hydroxocobalamin at pH 3 and pH 9 reduced the loss by only 6%. The results showed that cyanocobalamin was the most stable, followed by hydroxocobalamin and methylcobalamin. Added sorbitol was sufficient to significantly enhance the stability of cobalamins against degradative agents and conditions.

scholarly journals Investigation of Hydrothermally Stressed Silicone Rubber/Silica Micro and Nanocomposite for the Coating High Voltage Insulation Applications

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3567
Author(s):  
Faiza Faiza ◽  
Abraiz Khattak ◽  
Safi Ullah Butt ◽  
Kashif Imran ◽  
Abasin Ulasyar ◽  
...  
Keyword(s):  
Silicone Rubber ◽  
Structural Changes ◽  
Polymer Chains ◽  
Hydrothermal Conditions ◽  
Silica Filler ◽  
Before And After ◽  
Aging Conditions ◽  
The Stability ◽  
Micro Silica ◽  
Applied Stresses

Silicone rubber is a promising insulating material that has been performing well for different insulating and dielectric applications. However, in outdoor applications, environmental stresses cause structural and surface degradations that diminish its insulating properties. This effect of degradation can be reduced with the addition of a suitable filler to the polymer chains. For the investigation of structural changes and hydrophobicity four different systems were fabricated, including neat silicone rubber, a micro composite (with 15% micro-silica filler), and nanocomposites (with 2.5% and 5% nanosilica filler) by subjecting them to various hydrothermal conditions. In general, remarkable results were obtained by the addition of fillers. However, nanocomposites showed the best resistance against the applied stresses. In comparison to neat silicone rubber, the stability of the structure and hydrophobic behavior was better for micro-silica, which was further enhanced in the case of nanocomposites. The inclusion of 5% nanosilica showed the best results before and after applying aging conditions.

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