scholarly journals Comparison of Optical and Gravimetric Methods for Detection of Chymotrypsin

Proceedings ◽  
2020 ◽  
Vol 60 (1) ◽  
pp. 42
Author(s):  
Ivan Piovarci ◽  
Tibor Hianik ◽  
Ilia N. Ivanov
Keyword(s):  
Sample Preparation ◽  
Limit Of Detection ◽  
Optical Detection ◽  
Gravimetric Method ◽  
Milk Proteins ◽  
Industrial Processes

Proteases play an important role in various biological as well as dairy industrial processes. In this work, we focused on chymotrypsin, which is an important protease in human digestion. Chymotrypsin also cleaves milk proteins, which makes it useful in the study of activity of milk proteases. In this work, we focused on detection of chymotrypsin using optical and gravimetric techniques, their peculiarities, and the limit of detection (LOD) (0.15 ± 0.005 nM and 0.64 ± 0.31 nM for optical and gravimetric methods, respectively). While the optical detection is easier to implement, the gravimetric method is more robust for sample preparation. Both methods could represent a novel assay for detection of chymotrypsin and other milk proteases.

Determination of Free Solanesol Levels in Cigarette Filters by Liquid Chromatography–Mass Spectrometry

2021 ◽  
Author(s):  
Roberto Bravo Cardenas ◽  
Phuong Ngac ◽  
Clifford Watson ◽  
Liza Valentin-Blasini
Keyword(s):  
Liquid Chromatography ◽  
Sample Preparation ◽  
Tobacco Smoke ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Filter Material ◽  
Previous Method ◽  
Tobacco Smoke Exposure ◽  
Triple Quadrupole Mass Spectrometer ◽  
Cigarette Butts

Abstract Solanesol, a naturally occurring constituent of tobacco, has been utilized as a good marker for environmental tobacco smoke particulate and as a noninvasive predictor of mainstream cigarette smoke tar and nicotine intake under naturalistic smoking conditions. A fast and accurate method for measuring free solanesol to assess tobacco smoke exposure is highly desirable. We have developed and validated a new environmentally friendly, high-throughput method for measuring solanesol content in discarded cigarette filter butts. The solanesol deposited in the used filters can be correlated with mainstream smoke deliveries of nicotine and total particle matter to estimate constituent delivery to smokers. A portion of filter material is removed from cigarette butts after machine smoking, spiked with internal standard solution, extracted and quantitatively analyzed using reverse-phase liquid chromatography coupled to a triple-quadrupole mass spectrometer. The new method incorporates a 48-well plate format for automated sample preparation that reduces sample preparation time and solvent use and increases sample throughput 10-fold compared to our previous method. Accuracy and precision were evaluated by spiking known amounts of solanesol on both clean and smoked cigarette butts. Recoveries exceeded 93% at both low and high spiking levels. Linear solanesol calibration curves ranged from 1.9 to 367 µg/butt with a 0.05 µg/butt limit of detection.

Modern Methodological Approaches to Sample Preparation for the Determination of Trace Elements in Food Products and Plant Raw Materials

2021 ◽  
pp. 48-54
Author(s):  
NE Fedorova ◽  
MV Egorova ◽  
AS Rodionov
Keyword(s):  
High Resolution ◽  
Sample Preparation ◽  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Flame Atomic Absorption Spectrometry ◽  
Limit Of Detection ◽  
Absorption Spectrometry ◽  
Flame Atomic Absorption ◽  
Homogeneity Of Variances ◽  
Limit Of Quantitation

Introduction. Various copper compounds are most widely used as plant protection agents in agriculture. From a hygienic point of view, information on excessive accumulation of copper in plants related to the use of a specific formulation of copper-containing pesticides is of interest. Our objective was to assess feasibility of increasing statistical significance of results of determining low residue levels of a copper-containing pesticide in apple samples by flame atomic absorption spectrometry using a high-resolution spectrometer in combination with developed approaches to sample preparation of plant-based foods, including homogenization with dry ice and microwave mineralization. Materials and methods: We analyzed 30 samples of apples collected in three different agro-climatic zones by flame atomic absorption spectrometry and electrothermal atomization atomic absorption spectrometry. Both methods were validated on 10 samples with added copper at levels 1-5 of the lower limit of quantitation. A statistical calculation was performed based on a simple Student’s test to assess the significance of differences between the results of measurements by flame and electrothermal techniques. Homogeneity of variances was estimated using the Fisher test to clarify the possibility of comparing two data sets. Results: The use of a technique of cryo-grinding and microwave decomposition in a microwave reactor in combination with a high-resolution continuum source atomic absorption spectrometry demonstrated a decrease in scattering and the limit of detection and better repeatability in the analysis of parallel samples. Results of statistical calculations confirmed the homogeneity of variances in data samples obtained for electrothermal and flame techniques, and the further Student’s t-test showed insignificant differences between the results of measurements obtained by FAAS and ET-AAS. Conclusion: Our findings prove that modern methods of sample preparation in combination with highly sensitive equipment allow a significant reduction in the limit of detection and scattering of test results.

Imatinib quantification in human serum with LC-MS3 as an effective way of protein kinase inhibitor analysis in biological matrices

2017 ◽  
Vol 32 (3) ◽  
Author(s):  
Marek Dziadosz ◽  
Michael Klintschar ◽  
Jörg Teske
Keyword(s):  
Protein Kinase ◽  
Sample Preparation ◽  
Human Serum ◽  
Kinase Inhibitor ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Protein Kinase Inhibitor ◽  
Preparation Technique ◽  
Analytical Strategy ◽  
Inhibitor Analysis

AbstractBackground:As imatinib gained a lot of attention in the field of medicine, appropriate methods are needed for drug analysis. LC-MS/MS combined with complex sample preparation and column enrichment is usually the method of choice when high sensitivity is necessary. The application of LC-MSMethods:An LC-MSResults:The conditions applied resulted in a limit of detection/quantification value of 0.14/0.45 ng/mL reached without a sophisticated sample preparation technique or enrichment column application. It could be demonstrated that MSConclusions:The presented analytical strategy is an effective way of protein kinase inhibitor analysis in human serum.

scholarly journals Total Fat Gravimetric Method Workflow in Portuguese Olives Using Closed-Vessel Microwave-Assisted Extraction (MAE)

Foods ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2364
Author(s):  
João Gonçalo Lourenço ◽  
Daniel Ettlin ◽  
Inês Carrero Cardoso ◽  
Jesus M. Rodilla
Keyword(s):  
Limit Of Detection ◽  
Gravimetric Method ◽  
Reference Value ◽  
Microwave Assisted Extraction ◽  
Closed Vessel ◽  
Limit Of Quantification ◽  
Microwave Assisted ◽  
Assisted Extraction ◽  
Total Fat

A simple and rapid method for the quantitation of total fat in olive samples is designed, evaluated, and presented. This method is based on an innovative closed-vessel microwave-assisted extraction (MAE) technique. A method was designed for olives, and some figures of merits were evaluated: limit of detection (LOD), limit of quantification (LOQ) and expanded uncertainty (U). The data obtained in these experiences show that the workflow of the MAE method in a closed container is statistically equivalent to the other two methods, showing in this case better performance indicators (LOD = 0.02%, LOQ = 0.06%, and U = 15%). In addition, it is also demonstrated that the complete MAE method workflow allows the determination of total fat in a maximum of 12 analyses simultaneously for about 100 min in each run, which is the capacity of the rotor. This is a much better productivity when compared to the traditional Soxhlet-based method. Considering the sample workflow, the closed-vessel MAE method greatly simplifies sample handling, therefore minimizing sample loss during sample preparation and reducing analysis time. When MAE is compared to NIR-based methods, the advantage comes from there being no need for any type of calibration in the sample matrix. The MAE method itself can be used to determine the reference value for NIR calibration purposes. The results obtained for CRM using MAE were equivalent to the ones shown on the certificate.

P–006 Simultaneous determination of bisphenol A and S in the samples of human seminal fluid

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
S Fialková ◽  
T Král ◽  
J Kohoutek ◽  
K Franzová ◽  
M Ješeta ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Bisphenol A ◽  
Endocrine Disruptors ◽  
Analytical Method ◽  
Seminal Fluid ◽  
Limit Of Detection ◽  
Semen Parameters ◽  
Ms Detection ◽  
Validation Criteria ◽  
Limit Of Quantitation

Abstract Study question Can we quantitatively determine concentrations of endocrine disruptors namely bisphenol A and S in seminal fluid? Summary answer We developed selective analytical method to simultaneously screen for the presence of bisphenol A (BPA) and S (BPS). What is known already The male reproductive system involves processes, which may be influenced by the disruption of the endocrine system by chemicals called endocrine disruptors (EDs). There is a growing evidence that EDs such as bisphenol A and S may be responsible for the decline in male reproductive health. To date, the claimed adverse effects on male fertility are largely based on the results from studies assessing the relationship between urinary BPA and BPS concentration and semen parameters. The best evidence of an adverse effect of BPA and BPS directly on spermatozoa could be provided by measuring bisphenols concentration directly in seminal fluid. Study design, size, duration To selectively and quantitatively analyzed bisphenols in any biological matrix advanced analytical tools and selective sample preparation protocols must be employed. In this study we developed targeted analytical method based on liquid chromatography tandem mass (LC-MS/MS) detection to measure bisphenol A and S in seminal fluid samples obtained from IVF clinic. A total of 140 samples were analysed. Participants/materials, setting, methods BPA and BPS was extracted from 140 seminal fluid samples using solvent extraction followed by preconcentration step. Samples were analyzed on Agilent 6495 Triple Quadrupole (Agilent Technologies, Santa Clara, CA) operating in the ESI-negative mode. Two MS/MS transitions were used for quantitative LC-MS/MS analyses. Chromatographic separation was achieved on Waters™ ACQUITY™ UPLC™BEH C18 (100 × 2.1 mm, 1.7 µm) column using gradient elution with a mixture of 0.1mM ammonium fluoride and methanol as mobile phases. Main results and the role of chance We developed selective sample preparation method for detection of BPA and BPS in seminal fluid followed by LC-MS/MS detection. The method validation was performed based on FDA guidelines. Validation criteria included limit of detection (LOD), limit of quantitation (LOQ), accuracy and precision. Due to the lack of the certified reference material the validation criteria of the method were assessed in pool of spiked seminal samples. The accuracy of the LC-MS/MS method was evaluated as a percent recovery of the amount of target analyte added into the sample. Recovery rates were above 80% for both analytes. LOD was 0.04 ng/mL for BPA and 0.01 ng/mL for BPS. LOQ was 0.14 ng/mL and 0.02 ng/mL for BPS. Measured BPA concentration ranged from 0.04 ng/mL to 1.62 ng/mL. For BPS, the concentration ranged from 0.01 ng/mL to 0.47 ng/mL. BPA and BPS were detected in 64% and 81% of samples, respectively. Interestingly, BPA showed lower detection frequency compared to BPS. These results are consistent with other studies performed on urine samples. Limitations, reasons for caution The limitation of the developed method is the time-consuming sample preparation and analysis cost. Wider implications of the findings: These results document for the first time the presence of BPS in seminal fluid. Knowing the concentration of BPA and BPS in seminal fluid is crucial for mitigating the associated health risks and initiating intervention and prevention strategies. Our future work will evaluate the influence of BPS concentration on spermatozoa. Trial registration number AZV NV18–01–00544; CZ.02.2.69/0.0/0.0/19_074/0012727

scholarly journals The Measurement of Wood in Construction Dust Samples: A Furnace Based Thermal Gravimetric Approach

2019 ◽  
Vol 63 (9) ◽  
pp. 1070-1080
Author(s):  
Peter Stacey ◽  
Andrew Simpson ◽  
Susan Hambling
Keyword(s):  
Mineral Dust ◽  
Limit Of Detection ◽  
Rietveld Method ◽  
Gravimetric Method ◽  
Wood Dust ◽  
Thermal Gravimetric ◽  
Construction Sites ◽  
Quartz Fibre ◽  
Median Proportion ◽  
Inhalable Dust

Abstract A furnace-based thermal gravimetric method was developed to measure wood in inhalable construction dust. The application of this method showed that reliance on the inhalable concentrations alone may substantially overestimate carpenters’ exposures to wood dust at construction worksites. Test samples were prepared by collecting aerosols of gypsum, calcite, quartz, concrete, and wood dust onto quartz fibre filters using the Button inhalable sampler. The average difference between the measured and loaded mass of wood is 2% over the whole analytical range. Ninety percent of thermogravimetric measurements on all test samples (n = 35) were 13% or less. The limit of detection was measured as 0.065 mg. The thermal gravimetric method was applied to samples collected from four new build construction sites and one shop fitting worksite. The workplace inhalable wood dust results ranged from 15% to 104% of the total inhalable dust values. In addition, an x-ray diffraction (XRD) Rietveld method was applied as a complimentary approach to explain the composition of the remaining inhalable dust. Most combined thermal gravimetric and XRD measurements were within 10% of the total inhalable dust mass values, determined gravimetrically. Ninety-five percent were within 26%. The median proportion of mineral dust containing gypsum, calcite, quartz, dolomite, or rutile was 30%. The proportion of mineral dust on individual filters varied considerably.

scholarly journals Determination of Cyclamate in Foods by Ultraperformance Liquid Chromatography/Tandem Mass Spectrometry

2008 ◽  
Vol 91 (5) ◽  
pp. 1095-1102 ◽  
Author(s):  
Robert Sheridan ◽  
Thomas King
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Sample Preparation ◽  
Tandem Mass Spectrometry ◽  
Limit Of Detection ◽  
Tandem Mass ◽  
Chromatography Tandem Mass Spectrometry ◽  
Limit Of Quantitation ◽  
Liquid Chromatography Tandem Mass

Abstract A highly sensitive and selective method that requires minimal sample preparation was developed for the confirmation and quantitation of cyclamate in a variety of foods by high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS). Sample preparation consisted of homogenization followed by extraction and dilution of cyclamate with water. HPLC separation was achieved using a bridged ethyl hybrid C18 high-pressure column with a mobile phase consisting of 0.15 acetic acid and methanol. Under electrospray ionization negative conditions, quantitation was achieved by monitoring the fragment m/z 79.7 while also collecting parent ion m/z 177.9. Two food matrixes, diet soda and jelly, were subjected to a validation procedure in order to evaluate the applicability of the method. The cyclamate limit of detection for both matrixes was determined to be 0.050 g/g with a limit of quantitation of 0.150 g/g. The correlation coefficient of the calibration curves was >0.9998 from 0.0005 to 0.100 g/mL. The method has been used for the determination of cyclamate in several foods and the results are presented.

scholarly journals Total Arsenic, Cadmium, and Lead Determination in Brazilian Rice Samples Using ICP-MS

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Lidiane Raquel Verola Mataveli ◽  
Márcia Liane Buzzo ◽  
Luciana Juncioni de Arauz ◽  
Maria de Fátima Henriques Carvalho ◽  
Edna Emy Kumagai Arakaki ◽  
...  
Keyword(s):  
Sample Preparation ◽  
Limit Of Detection ◽  
Brown Rice ◽  
Total Arsenic ◽  
Limit Of Quantification ◽  
Rice Sample ◽  
Icp Ms ◽  
Validation Parameters ◽  
Rice Samples ◽  
Cadmium And Lead

This study is aimed at investigating a suitable method for rice sample preparation as well as validating and applying the method for monitoring the concentration of total arsenic, cadmium, and lead in rice by using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Various rice sample preparation procedures were evaluated. The analytical method was validated by measuring several parameters including limit of detection (LOD), limit of quantification (LOQ), linearity, relative bias, and repeatability. Regarding the sample preparation, recoveries of spiked samples were within the acceptable range from 89.3 to 98.2% for muffle furnace, 94.2 to 103.3% for heating block, 81.0 to 115.0% for hot plate, and 92.8 to 108.2% for microwave. Validation parameters showed that the method fits for its purpose, being the total arsenic, cadmium, and lead within the Brazilian Legislation limits. The method was applied for analyzing 37 rice samples (including polished, brown, and parboiled), consumed by the Brazilian population. The total arsenic, cadmium, and lead contents were lower than the established legislative values, except for total arsenic in one brown rice sample. This study indicated the need to establish monitoring programs for emphasizing the study on this type of cereal, aiming at promoting the Public Health.

Bioanalysis - Method Development, Validation, Sample Preparation, its Detection Techniques and its Application

2021 ◽  
pp. 297-305
Author(s):  
Seema R. Nikam ◽  
Amol S. Jagdale ◽  
Sahebrao S. Boraste ◽  
Shrikant B Patil
Keyword(s):  
Sample Preparation ◽  
Method Development ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Bioequivalence Study ◽  
Time Frame ◽  
Biological Drugs ◽  
Detection Techniques ◽  
Validation Parameters ◽  
Limit Of Quantitation

Quantitatively measurements of chemical and biological drugs and their metabolites in the biological sample. This used in clinical and non-clinical studies. Non clinical including Pharmacokinetic and Toxic kinetic study, and clinical including Bioavailability, Bioequivalence study. This are play significant role and help in improvement in technology and analytical methods. Recent years have witnessed the introduction of several high- quality review articles into the literature covering various scientific and technical aspects of bioanalysis. Method validation and development use for the purpose of suitability of method for their intended purpose, this are important in Drug Discovery and Development. It including a validation parameters are Accuracy, Precision, Range, Calibration Curve, Recovery, Limit of Detection, Limit of Quantitation, Specificity, Selectivity and Stability, Ruggedness. This applicable in bio analysis, FDA and EMA guidelines. There are 3 main Extraction techniques used in sample preparation in bioanalysis is precipitation, liquid –liquid extraction, solid phase extraction. Detection of analyte by using hyphenated and chromatographic techniques like LC-MS/MS, HPLC, GC-MS. This LC-MS/MS is commonly used in a bioanalysis. This bio analysis study used in Pharmaceutical, Biomedical research purpose. Many challenges in pharmaceutical industry that fulfill by the utilization of analytical technologies and high-throughput automated platforms has been employed; in order to perform more experiments in a shorter time frame with increased data quality.

Excellence in Laboratory Practice with the Validation of Opiate Confirmation using Liquid Chromatography/Mass Spectrometry

2021 ◽  
Vol 156 (Supplement_1) ◽  
pp. S34-S34
Author(s):  
S Dalal ◽  
D Jhala
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Sample Preparation ◽  
Drugs Of Abuse ◽  
Limit Of Detection ◽  
Gas Chromatography Mass Spectrometry ◽  
Liquid Chromatography Mass Spectrometry ◽  
Laboratory Practice ◽  
Ion Suppression ◽  
Chromatography Mass Spectrometry

Abstract Introduction/Objective Veterans are more susceptible to opioid addiction as they are more likely to suffer from chronic pain which leads to increased need of confirmed identification of opiates in toxicology laboratories. Gas chromatography-mass spectrometry (GC-MS) had been a long-accepted method for the quantitative analysis of opiates in urine, but requires tedious, time-consuming, and complex sample preparation steps. On the other hand, liquid chromatography-mass spectrometry (LC/MS) has comparatively simpler sample preparation steps, can handle three times the number of specimens, much faster turnaround times and produces equally valid results. However, the validation experience of this simpler detection method has not been well published, particularly in a Veterans Healthcare Clinical Laboratory setting. Methods/Case Report The quality assurance goal of the validation is to demonstrate that the Agilent 6410 Triple Quadrupole LC/MS (Wilmington DE) is able to identify the same opiate drug analytes performed by the GC-MS. Method to method correlation, within run precision, day to day precision, carryover study, matrix (ion) suppression study, and a limit of detection study were performed as part of this validation. Results (if a Case Study enter NA) For the total of 156 specimens run for the method comparison, there was 94.9% agreement, or 148/156 samples were concordant. The 8 discrepancies had drugs that were present below the cutoff limit of the LC/MS. Within run precision with 20 replicates of negative, positive, and at the cutoff were run with all results as expected. The day to day precision of a positive and negative sample run over 10 days also yielded results as expected. The carryover study demonstrated minimal carryover. The matrix (ion) suppression study showed ion suppression at 16.8%, which is below the amount needed to affect analyte concentrations. The LC/MS was highly sensitive with a limit of detection of >97% at 25 ng/mL. Thus, the result of comparison showed good concordance. Conclusion LC/MS is a simpler, more efficient method of opiate testing that is comparable to GC-MS for the detection of opiate drugs of abuse in urine. This is an example of excellence in laboratory practice by extending the best quality laboratory care with proper validation of instrument methods conducive to laboratory workflow.

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