MyMedR

Displaying publications 1 - 20 of 60 in total

Abstract:

Sort:

An Application of pET SUMO Protein Expression System in Escherichia coli: Cloning, Expression, Purification, and Characterisation of Native Kras4BG12V Oncoprotein

Tan MS, Teh YH, Ho KL, Stanslas J

Protein J, 2020 02;39(1):54-61.
PMID: 31620959 DOI: 10.1007/s10930-019-09872-1

Being an important regulator of cell growth and survival, a point mutation at glycine-12 residue of Kras4B to valine (V), renders Kras4BG12V oncogenic. Kras4B recombinant protein is used as a bait to fish its potential ligands in the attempt of drugging this oncoprotein and to validate its pharmacologically relevant ligand in protein-ligand interaction studies. Nevertheless, synthesis of Kras4B recombinant protein is challenging as it was reported being susceptible to aggregation into inclusion bodies in the bacterial host, resulting in a poor yield of recombinant protein. Here, we describe a novel method to produce native Kras4BG12V protein by using pET SUMO protein expression system as a solution to the formation of inclusion bodies. Kras4BG12V oncogene was cloned into pET SUMO vector, followed by a 12 h chemically induced protein expression in Escherichia coli at 20 °C. Native Kras4BG12V protein was produced in a series of protein purification steps involving immobilised nickel ion-affinity column chromatography, SUMO fusion protein and polyhistidine tag removal, and size exclusion column chromatography. The identity of the purified Kras4BG12V protein was validated by immunoblot analysis. The purified protein exhibited self-dimerising, indicating that the purified protein structurally resembles Kras4B. Its physical interaction with 4,6-dichloro-2-methyl-3-aminoethyl-indole (DCAI), a known binder of Kras4B, confirms the identity of the purified protein as Kras4BG12V. The native Kras4BG12V protein was successfully purified in a substantial amount by using the pET SUMO protein expression system.

Matched MeSH terms: Chromatography, Liquid/methods
Pharmacokinetic-pharmacodynamic study of subcutaneous injection of depot nandrolone decanoate using dried blood spots sampling coupled with ultrapressure liquid chromatography tandem mass spectrometry assays

Singh GK, Turner L, Desai R, Jimenez M, Handelsman DJ

J Clin Endocrinol Metab, 2014 Jul;99(7):2592-8.
PMID: 24684468 DOI: 10.1210/jc.2014-1243

Testosterone (T) and nandrolone (N) esters require deep im injections by medical personnel but these often deposit injectate into sc fat so that more convenient sc self-administration may be feasible.

Matched MeSH terms: Chromatography, Liquid/methods
Determination of phosphodiesterase 5 (PDE5) inhibitors in instant coffee premixes using liquid chromatography-high-resolution mass spectrometry (LC-HRMS)

Mohd Yusop AY, Xiao L, Fu S

Talanta, 2019 Nov 01;204:36-43.
PMID: 31357306 DOI: 10.1016/j.talanta.2019.05.078

As a widely consumed beverage, coffee tends to be a target for intentional adulteration. This study describes the application of modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) coupled to liquid chromatography-high-resolution mass spectrometry (LC-HRMS) for simultaneous screening, identification, and quantification of undeclared phosphodiesterase 5 (PDE5) inhibitors in instant coffee premixes (ICPs). The mass spectrometer was operated in auto MS/MS acquisition for simultaneous MS and MS/MS experiments. Qualitative establishments from the suspected-target screening and targeted identification processes led to an unambiguous analyte assignment from the protonated molecule ([M+H]+) precursor ion which is subsequently used for quantification of 23 targeted PDE5 inhibitors. The analytical method validation covered specificity, linearity, range, accuracy, limit of detection (LOD), limit of quantification (LOQ), precisions, matrix effect (ME), and extraction recovery (RE). The specificity was established using the optimised chromatographic separation as well as the distinguishable [M+H]+ precursor ion. The linearity of each target analyte was demonstrated with a coefficient of determination (r2) of >0.9960 over the expected range of sample concentrations. The accuracy ranged from 88.1%-119.3% with LOD and LOQ of <70 ng/mL and 80 ng/mL, respectively. Excellent precisions were established within 0.4%-9.1% of the relative standard deviation. An insignificant ME within -5.2% to +8.7% was achieved using three different strategies of chromatography, sample extraction, and sample dilution. The RE was good for all target analytes within 84.7%-123.5% except for N-desethylacetildenafil at low (53.8%) and medium (65.1%) quality control levels. The method was successfully applied to 25 samples of ICPs where 17 of them were found to be adulterated with PDE5 inhibitors and their analogues. Further quantification revealed the total amount of these adulterants ranged from 2.77 to 121.64 mg per sachet.

Matched MeSH terms: Chromatography, Liquid/methods*
An improved SPE-LC-MS/MS method for multiclass endocrine disrupting compound determination in tropical estuarine sediments

Omar TFT, Aris AZ, Yusoff FM, Mustafa S

Talanta, 2017 Oct 01;173:51-59.
PMID: 28602191 DOI: 10.1016/j.talanta.2017.05.064

Estuary sediments are one of the important components of coastal ecosystems and have been regarded as a sink for various types of organic pollutants. Organic pollutants such as endocrine disrupting compounds (EDCs) which have been associated with various environmental and human health effects were detected in the estuary sediment at trace level. Considering various interferences that may exist in the estuarine sediment, a sensitive and selective method, capable of detecting multiclass EDC pollutants at the trace levels, needs to be developed and optimized to be applied for environmental analysis. A combination of Soxhlet extraction followed by offline solid phase extraction (SPE) cleaned up with detection based on LC triple quadrupole MS was optimized and validated in this study. The targeted compounds consisted of ten multiclass EDCs, namely, diclofenac, primidone, bisphenol A, estrone (E1), 17β-estradiol (E2), 17α-ethynylestradiol (EE2), 4-octylphenol (4-OP), 4-nonylphenol (4-NP), progesterone, and testosterone. The method showed high extraction efficiency with percentage of recovery from 78% to 108% and excellent sensitivity with detection limit between 0.02ngg-1 and 0.81ngg-1. Excellent linearity from 0.991 to 0.999 was achieved for the developed compounds and the relative standard deviation was less than 18%, an indication of good precision analysis. Evaluation of the matrix effects showed ionization suppression for all the developed compounds. Verification of the method was carried out by analyzing the estuarine sediment collected from Langat River. The analyzed estuarine sediments showed a trace concentration of diclofenac, bisphenol A, progesterone, testosterone, primidone, and E1. However, E2, EE2, 4-OP, and 4-NP were below the method's detection limit. Diclofenac exhibited the highest concentration at 2.67ngg-1 followed by bisphenol A (1.78ngg-1) while E1 showed the lowest concentration at 0.07ngg-1.

Matched MeSH terms: Chromatography, Liquid/methods*
Poly-(MMA-IL) filter paper: A new class of paper-based analytical device for thin-film microextraction of multi-class antibiotics in environmental water samples using LC-MS/MS analysis

Shahriman MS, Mohamad S, Mohamad Zain NN, Raoov M

Talanta, 2023 Mar 01;254:124188.
PMID: 36521327 DOI: 10.1016/j.talanta.2022.124188

A paper-based polymeric ionic liquid (p-Poly-(MMA-IL)) was successfully developed by grafting the polymeric ionic liquid on the surface of commercial filter paper (FP) by using the dipping method, presenting a new cost-effective film. The newly developed p-Poly-(MMA-IL) FP was then applied as a paper-based thin-film microextraction (p-TFME) analytical device to extract 14 compounds as representative of five groups of antibiotic drugs, which were sulfonamides, tetracyclines, fluoroquinolones, penicillin and macrolides in environmental water samples. Besides, p-Poly-(MMA-IL) FP, p-Poly-(MMA) FP, and unmodified filter paper were successfully characterised by FTIR, NMR, FESEM, TGA, and XRD techniques. They underwent significant parameters optimisation, which affected the extraction efficiency. Under optimal conditions, the proposed (p-Poly-(MMA-IL) FP-TFME) device method was evaluated and applied to analyse multi-class antibiotic drugs in environmental water samples by using a liquid chromatography-mass spectrometry (LC-MS). The validation method showed that a good linearity (0.1 μg L-1 - 500 μg L-1) was noted (R2 > 0.993, n = 3). Detection and quantification limits were within 0.05 μg L-1 - 4.52 μg L-1 and 0.15 μg L-1 - 13.6 μg L-1, respectively. The relative standard deviation (RSD) values ranged at 1.4%-12.2% (intra-day, n = 15) and 4.4%-11.0% (inter-day, n = 10). The extraction recoveries of environmental water samples ranged from 79.1% to 126.8%, with an RSD of less than 15.4% (n = 3). The newly developed paper-based polymeric ionic liquid (p-Poly-(MMA-IL) FP) for analysis of multi-class antibiotic drugs under the p-TFME analytical device procedure was successfully achieved with limited sample volume and organic solvent, fast extraction, and feasible in daily analysis. The detection concentration and relative RSD of multi-class antibiotics determined in various environmental water samples by the proposed method (n = 5) were within 0.44 μg L-1 - 54.41 μg L-1 and 0.69%-15.56%, respectively. These results signified the potential of the p-Poly-(MMA-IL) FP-TFME device as an efficient, sensitive and environmentally friendly approach for analysing antibiotics.

Matched MeSH terms: Chromatography, Liquid/methods
Fulltext Detection of quorum sensing activity in the multidrug-resistant clinical isolate Pseudomonas aeruginosa strain GB11

Cheng HJ, Ee R, Cheong YM, Tan WS, Yin WF, Chan KG

Sensors (Basel), 2014;14(7):12511-22.
PMID: 25019635 DOI: 10.3390/s140712511

A multidrug-resistant clinical bacteria strain GB11 was isolated from a wound swab on the leg of a patient. Identity of stain GB11 as Pseudomonas aeruginosa was validated by using matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Detection of the production of signaling molecules, N-acylhomoserine lactones (AHLs), was conducted using three different bacterial biosensors. A total of four different AHLs were found to be produced by strain GB11, namely N-butyryl homoserine lactone (C4-HSL), N-hexanoylhomoserine lactone (C6-HSL), N-octanoyl homoserine lactone (C8-HSL) and N-3-oxo-dodecanoylhomoserine lactone (3-oxo-C12-HSL) using high resolution liquid chromatography tandem mass spectrometry (LC-MS/MS). Of these detected AHLs, 3-oxo-C12-HSL was found to be the most abundant AHL produced by P. aeruginosa GB11.

Matched MeSH terms: Chromatography, Liquid/methods
Glutathione conjugation of nitrogen mustards: In vitro study

Hamzah N, Kjellberg M, Vanninen P

Rapid Commun Mass Spectrom, 2023 May 15;37(9):e9495.
PMID: 36799074 DOI: 10.1002/rcm.9495

RATIONALE: This paper describes an in vitro study designed to identify metabolic biomarkers resulting from the conjugation of nitrogen mustards (NMs) with glutathione (GSH). The method developed is essential in providing evidence in the event of NM exposure in biomedical samples.
METHODS: The mass spectral characterization of the proposed NMs-GSH conjugates was performed with liquid chromatography high-resolution tandem mass spectrometry (LC-HRMS/MS). The final reaction mixtures were analysed in positive electrospray ionisation (ESI) at different incubation times.
RESULTS: This study identified three types of conjugates in addition to ethanolamines, the hydrolysis products of NMs. Monoglutathionyl, diglutathionyl and phosphorylated conjugates were produced for each of the NMs, bis(2-chloroethyl)ethylamine (HN1), bis(2-chloroethyl)methylamine (HN2) and tris(2-chloroethyl)amine (HN3). The monoglutathionyl conjugates consisted of HN1-GSH, HN2-GSH and HN3-GSH. The spontaneous and primary conjugates of diglutathionyl were HN1-GSH2, HN2-GSH2 and HN3-GSH2. These included phosphorylated conjugates, namely HN1-GSH-PO4 , HN2-GSH-PO4 and HN3-GSH-PO4 , as might have formed due to hydrolysis in phosphate buffer.
CONCLUSIONS: The mass spectral data of all conjugates formed in the presence of all NMs and GSH are reported in this study. These GSH metabolites can be used to confirm NMs toxicity in biological samples such as urine.

Matched MeSH terms: Chromatography, Liquid/methods
Fulltext Multicomponent carbohydrase system from Trichoderma reesei: A toolbox to address complexity of cell walls of plant substrates in animal feed

Rangel Pedersen N, Tovborg M, Soleimani Farjam A, Della Pia EA

PLoS One, 2021;16(6):e0251556.
PMID: 34086701 DOI: 10.1371/journal.pone.0251556

A diverse range of monocot and dicot grains and their by-products are commonly used in the animal feed industry. They all come with complex and variable cell wall structures which in turn contribute significant fiber to the complete feed. The cell wall is a highly interconnected matrix of various polysaccharides, proteins and lignin and, as such, requires a collaborative effort of different enzymes for its degradation. In this regard, we investigated the potential of a commercial multicomponent carbohydrase product from a wild type fermentation of Trichoderma reesei (T. reesei) (RONOZYME® MultiGrain) in degrading cell wall components of wheat, barley, rye, de-oiled rice bran, sunflower, rapeseed and cassava. A total of thirty-one different enzyme proteins were identified in the T. Reesei carbohydrase product using liquid chromatography with tandem mass spectrometry LC-MS/MS including glycosyl hydrolases and carbohydrate esterases. As measured by in vitro incubations and non-starch polysaccharide component analysis, and visualization by immunocytochemistry and confocal microscopy imaging of immuno-labeled samples with confocal microscopy, the carbohydrase product effectively solubilized cellulolytic and hemicellulolytic polysaccharides present in the cell walls of all the feed ingredients evaluated. The T. reesei fermentation also decreased viscosity of arabinoxylan, xyloglucan, galactomannan and β-glucan substrates. Combination of several debranching enzymes including arabinofuranosidase, xylosidase, α-galactosidase, acetyl xylan esterase, and 4-O-methyl-glucuronoyl methylesterase with both GH10 and GH11 xylanases in the carbohydrase product resulted in effective hydrolyzation of heavily branched glucuronoarabinoxylans. The different β-glucanases (both endo-β-1,3(4)-glucanase and endo-β-1,3-glucanase), cellulases and a β-glucosidase in the T. reesei fermentation effectively reduced polymerization of both β-glucans and cellulose polysaccharides of viscous cereals grains (wheat, barley, rye and oat). Interestingly, the secretome of T. reesei contained significant amounts of an exceptional direct chain-cutting enzyme from the GH74 family (Cel74A, xyloglucan-specific β-1,4-endoglucanase), that strictly cleaves the xyloglucan backbone at the substituted regions. Here, we demonstrated that the balance of enzymes present in the T. reesei secretome is capable of degrading various cell wall components in both monocot and dicot plant raw material used as animal feed.

Matched MeSH terms: Chromatography, Liquid/methods
Rapid identification of cyclic tetrapyrrolic photosensitisers for photodynamic therapy using on-line hyphenated LC-PDA-MS coupled with photo-cytotoxicity assay

Tan PJ, Appleton DR, Mustafa MR, Lee HB

Phytochem Anal, 2012 Jan-Feb;23(1):52-9.
PMID: 21692117 DOI: 10.1002/pca.1324

Photodynamic therapy is a treatment modality that involves site-directed generation of cytotoxic reactive oxygen species by light-activated photosensitisers.

Matched MeSH terms: Chromatography, Liquid/methods*
1 H-NMR metabolomics for evaluating the protective effect of Clinacanthus nutans (Burm. f) Lindau water extract against nitric oxide production in LPS-IFN-γ activated RAW 264.7 macrophages

Khoo LW, Kow ASF, Maulidiani M, Ang MY, Chew WY, Lee MT, et al.

Phytochem Anal, 2019 Jan;30(1):46-61.
PMID: 30183131 DOI: 10.1002/pca.2789

INTRODUCTION: Clinacanthus nutans, a small shrub that is native to Southeast Asia, is commonly used in traditional herbal medicine and as a food source. Its anti-inflammation properties is influenced by the metabolites composition, which can be determined by different binary extraction solvent ratio and extraction methods used during plant post-harvesting stage.
OBJECTIVE: Evaluate the relationship between the chemical composition of C. nutans and its anti-inflammatory properties using nuclear magnetic resonance (NMR) metabolomics approach.
METHODOLOGY: The anti-inflammatory effect of C. nutans air-dried leaves extracted using five different binary extraction solvent ratio and two extraction methods was determined based on their nitric oxide (NO) inhibition effect in lipopolysaccharide-interferon-gamma (LPS-IFN-γ) activated RAW 264.7 macrophages. The relationship between extract bioactivity and metabolite profiles and quantifications were established using 1 H-NMR metabolomics and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The possible metabolite biosynthesis pathway was constructed to further strengthen the findings.
RESULTS: Water and sonication prepared air-dried leaves possessed the highest NO inhibition activity (IC50 = 190.43 ± 12.26 μg/mL, P

Matched MeSH terms: Chromatography, Liquid/methods
α-glucosidase inhibitors isolated from Mimosa pudica L

Tasnuva ST, Qamar UA, Ghafoor K, Sahena F, Jahurul MHA, Rukshana AH, et al.

Nat Prod Res, 2019 May;33(10):1495-1499.
PMID: 29281898 DOI: 10.1080/14786419.2017.1419224

The aim of the study was to isolate digestive enzymes inhibitors from Mimosa pudica through a bioassay-guided fractionation approach. Repeated silica gel and sephadex LH 20 column chromatographies of bioactive fractions afforded stigmasterol, quercetin and avicularin as digestive enzymes inhibitors whose IC50 values as compared to acarbose (351.02 ± 1.46 μg mL-1) were found to be as 91.08 ± 1.54, 75.16 ± 0.92 and 481.7 ± 0.703 μg mL-1, respectively. In conclusion, M. pudica could be a good and safe source of digestive enzymes inhibitors for the management of diabetes in future.

Matched MeSH terms: Chromatography, Liquid/methods
Fulltext Capsaicin and dihydrocapsaicin determination in chili pepper genotypes using ultra-fast liquid chromatography

Usman MG, Rafii MY, Ismail MR, Malek MA, Latif MA

Molecules, 2014 May 21;19(5):6474-88.
PMID: 24853712 DOI: 10.3390/molecules19056474

Research was carried out to estimate the levels of capsaicin and dihydrocapsaicin that may be found in some heat tolerant chili pepper genotypes and to determine the degree of pungency as well as percentage capsaicin content of each of the analyzed peppers. A sensitive, precise, and specific ultra fast liquid chromatographic (UFLC) system was used for the separation, identification and quantitation of the capsaicinoids and the extraction solvent was acetonitrile. The method validation parameters, including linearity, precision, accuracy and recovery, yielded good results. Thus, the limit of detection was 0.045 µg/kg and 0.151 µg/kg for capsaicin and dihydrocapsaicin, respectively, whereas the limit of quantitation was 0.11 µg/kg and 0.368 µg/kg for capsaicin and dihydrocapsaicin. The calibration graph was linear from 0.05 to 0.50 µg/g for UFLC analysis. The inter- and intra-day precisions (relative standard deviation) were <5.0% for capsaicin and <9.9% for dihydrocapsaicin while the average recoveries obtained were quantitative (89.4%-90.1% for capsaicin, 92.4%-95.2% for dihydrocapsaicin), indicating good accuracy of the UFLC method. AVPP0705, AVPP0506, AVPP0104, AVPP0002, C05573 and AVPP0805 showed the highest concentration of capsaicin (12,776, 5,828, 4,393, 4,760, 3,764 and 4,120 µg/kg) and the highest pungency level, whereas AVPP9703, AVPP0512, AVPP0307, AVPP0803 and AVPP0102 recorded no detection of capsaicin and hence were non-pungent. All chili peppers studied except AVPP9703, AVPP0512, AVPP0307, AVPP0803 and AVPP0102 could serve as potential sources of capsaicin. On the other hand, only genotypes AVPP0506, AVPP0104, AVPP0002, C05573 and AVPP0805 gave a % capsaicin content that falls within the pungency limit that could make them recommendable as potential sources of capsaicin for the pharmaceutical industry.

Matched MeSH terms: Chromatography, Liquid/methods*
Fulltext Development of Chromatographic Fingerprints of Eurycoma longifolia (Tongkat Ali) Roots Using Online Solid Phase Extraction-Liquid Chromatography (SPE-LC)

Zaini NN, Osman R, Juahir H, Saim N

Molecules, 2016 Apr 30;21(5).
PMID: 27144555 DOI: 10.3390/molecules21050583

E. longifolia is attracting interest due to its pharmacological properties and pro-vitality effects. In this study, an online SPE-LC approach using polystyrene divinyl benzene (PSDVB) and C18 columns was developed in obtaining chromatographic fingerprints of E. longifolia. E. longifolia root samples were extracted using pressurized liquid extraction (PLE) technique prior to online SPE-LC. The effects of mobile phase compositions and column switching time on the chromatographic fingerprint were optimized. Validation of the developed method was studied based on eurycomanone. Linearity was in the range of 5 to 50 µg∙mL(-1) (r² = 0.997) with 3.2% relative standard deviation of peak area. The developed method was used to analyze 14 E. longifolia root samples and 10 products (capsules). Selected chemometric techniques: cluster analysis (CA), discriminant analysis (DA), and principal component analysis (PCA) were applied to the fingerprint datasets of 37 selected peaks to evaluate the ability of the chromatographic fingerprint in classifying quality of E. longifolia. Three groups were obtained using CA. DA yielded 100% correlation coefficient with 19 discriminant compounds. Using PCA, E. longifolia root samples were clearly discriminated from the products. This study showed that the developed online SPE-LC method was able to provide comprehensive evaluation of E. longifolia samples for quality control purposes.

Matched MeSH terms: Chromatography, Liquid/methods*
Fulltext Pharmacokinetics and Metabolism of Liposome-Encapsulated 2,4,6-Trihydroxygeranylacetophenone in Rats Using High-Resolution Orbitrap Liquid Chromatography Mass Spectrometry

Alkhateeb Y, Jarrar QB, Abas F, Rukayadi Y, Tham CL, Hay YK, et al.

Molecules, 2020 Jul 06;25(13).
PMID: 32640512 DOI: 10.3390/molecules25133069

2,4,6-trihydroxy-3-geranylacetophenone (tHGA) is a bioactive compound that shows excellent anti-inflammatory properties. However, its pharmacokinetics and metabolism have yet to be evaluated. In this study, a sensitive LC-HRMS method was developed and validated to quantify tHGA in rat plasma. The method showed good linearity (0.5-80 ng/mL). The accuracy and precision were within 10%. Pharmacokinetic investigations were performed on three groups of six rats. The first two groups were given oral administrations of unformulated and liposome-encapsulated tHGA, respectively, while the third group received intraperitoneal administration of liposome-encapsulated tHGA. The maximum concentration (Cmax), the time required to reach Cmax (tmax), elimination half-life (t1/2) and area under curve (AUC0-24) values for intraperitoneal administration were 54.6 ng/mL, 1.5 h, 6.7 h, and 193.9 ng/mL·h, respectively. For the oral administration of unformulated and formulated tHGA, Cmax values were 5.4 and 14.5 ng/mL, tmax values were 0.25 h for both, t1/2 values were 6.9 and 6.6 h, and AUC0-24 values were 17.6 and 40.7 ng/mL·h, respectively. The liposomal formulation improved the relative oral bioavailability of tHGA from 9.1% to 21.0% which was a 2.3-fold increment. Further, a total of 12 metabolites were detected and structurally characterized. The metabolites were mainly products of oxidation and glucuronide conjugation.

Matched MeSH terms: Chromatography, Liquid/methods*
Fulltext Liquid Chromatographic Tandem Mass Spectrometric (LC-MS/MS) Determination of Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoic Acid (PFOA) in the Yolk of Poultry Eggs in Malaysia

Tahziz A, Mohamad Haron DE, Aziz MY

Molecules, 2020 May 16;25(10).
PMID: 32429475 DOI: 10.3390/molecules25102335

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are widely used in products, and are known for their water and grease repellent properties. The persistence nature and potential toxicity of these substances have raised substantial concerns about health effects. Regarding humans, food consumption has reportedly been a significant source of exposure for both compounds. Hence, this study was performed to develop and validate an analytical method for PFOS and PFOA in egg yolks using liquid chromatographic tandem mass spectrometry (LC-MS/MS) followed by the determination of concentration of both compounds in the yolk of poultry eggs in Malaysia. A total of 47 poultry egg yolk samples were extracted by a simple protein precipitation technique using acetonitrile. The analytical method was developed using LC-MS/MS and validated based on the Food and Drug Administration (FDA)'s Bioanalytical Method Validation guidelines. The results revealed that PFOS was quantitatively detected in six samples, with the concentration range between 0.5 and 1.01 ng g-1. Among these, five samples were from home-produced chicken eggs, and one sample was from a quail egg. The levels of PFOA in all samples were below the quantifiable limit (<0.1 ng g-1). This indicated that the contamination of PFCs in poultry eggs were mostly attributed to the nature of free foraging animals, which had direct contact with the contaminants in soil and feed. In conclusion, a fast and robust analytical method for analyzing PFOS and PFOA in egg yolk samples using LC-MS/MS was successfully developed and validated. The presence of these emerging contaminants in this study signified widespread pollution in the environment.

Matched MeSH terms: Chromatography, Liquid/methods*
Fulltext Development of Ultra-Performance Liquid Chromatography-Mass Spectrometry Method for Simultaneous Determination of Three Cationic Dyes in Environmental Samples

Hakami AAH, Wabaidur SM, Ali Khan M, Abdullah Alothman Z, Rafatullah M, Siddiqui MR

Molecules, 2020 Oct 06;25(19).
PMID: 33036289 DOI: 10.3390/molecules25194564

Lower dye concentrations and the presence of several dyes along with other matrices in environmental samples restrict their determination. Herein, a highly sensitive and rapid ultra-performance tandem mass spectrometric method was developed for simultaneous determination of cationic dyes, namely methylene blue (MB), rhodamine B (RB) and crystal violet (CV), in environmental samples. To preconcentrate environmental samples, solid-phase extraction cartridges were developed by using hydrogen peroxide modified pistachio shell biomass (MPSB). The surface morphological and chemical functionalities of MPSB were well characterized. The developed method was validated considering different validation parameters. In terms of accuracy and precision, the %RSD for all three dyes at all four concentration points was found to be between 1.26 and 2.76, while the accuracy reported in terms of the recovery was found to be 98.02%-101.70%. The recovery was found to be in the range of 98.11% to 99.55%. The real sample analysis shows that MB, RB, and CV were found in the ranges of 0.39-5.56, 0.32-1.92 and 0.27-4.36 μg/mL, respectively.

Matched MeSH terms: Chromatography, Liquid/methods*
Quantification of nimetazepam and its metabolite in human hair samples using liquid chromatography-tandem mass spectrometry: Case report

Dai Y, Han L, Wang Y, Zhao K, Gu J, Bai H, et al.

Leg Med (Tokyo), 2023 Nov;65:102303.
PMID: 37598646 DOI: 10.1016/j.legalmed.2023.102303

Nimetazepam (marketed brand names; Erimin and Lavol) is an intermediate acting benzodiazepine derivative, which was widely used mainly in East and Southeast Asian region countries including Japan, Malaysia, Brunei, the Philippines, Thailand, Indonesia, Hong Kong, Singapore and China. Nimetazepam and its metabolite 7-aminonimetazepam were quantified from human hair samples by liquid chromatography tandem-mass spectrometry (LC-MS/MS), under selective reaction monitoring mode. Using diazepam-d5 as an internal standard, the concentration of nimetazepam and its metabolite 7-aminonimetazepam could be determined by matrix matched calibration method. Extraction of the target compounds was performed by using methanol, followed by evaporation and being concentrated with nitrogen. The Limit of quantification concentrations of nimetazepam and its metabolite 7-aminonimetazepam in hair samples were both 25 pg/mg by established method. The concentrations of nimetazepam in hair samples obtained from 2 users were 27.4, and 22.0 pg/mg, respectively; the concentrations of 7-animonimetazepam in hair samples were 54.2 and 29.1 pg/mg, respectively. In our study, the 7-aminonimetazepam concentrations in hair was higher than those of nimetazepam in the authentic hair samples. To our knowledge, this is the first report to establish the detailed procedure for quantificating nimetazepam and 7-aminonimetazepam in human hair by LC-MS/MS.

Matched MeSH terms: Chromatography, Liquid/methods
Determination of partition coefficient and analysis of nitrophenols by three-phase liquid-phase microextraction coupled with capillary electrophoresis

Sanagi MM, Miskam M, Wan Ibrahim WA, Hermawan D, Aboul-Enein HY

J Sep Sci, 2010 Jul;33(14):2131-9.
PMID: 20549667 DOI: 10.1002/jssc.201000172

A three-phase hollow fiber liquid-phase microextraction method coupled with CE was developed and used for the determination of partition coefficients and analysis of selected nitrophenols in water samples. The selected nitrophenols were extracted from 14 mL of aqueous solution (donor solution) with the pH adjusted to pH 3 into an organic phase (1-octanol) immobilized in the pores of the hollow fiber and finally backextracted into 40.0 microL of the acceptor phase (NaOH) at pH 12.0 located inside the lumen of the hollow fiber. The extractions were carried out under the following optimum conditions: donor solution, 0.05 M H(3)PO(4), pH 3.0; organic solvent, 1-octanol; acceptor solution, 40 microL of 0.1 M NaOH, pH 12.0; agitation rate, 1050 rpm; extraction time, 15 min. Under optimized conditions, the calibration curves for the analytes were linear in the range of 0.05-0.30 mg/L with r(2)>0.9900 and LODs were in the range of 0.01-0.04 mg/L with RSDs of 1.25-2.32%. Excellent enrichment factors of up to 398-folds were obtained. It was found that the partition coefficient (K(a/d)) values were high for 2-nitrophenol, 3-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol and 2,6-dinitrophenol and that the individual partition coefficients (K(org/d) and K(a/org)) promoted efficient simultaneous extraction from the donor through the organic phase and further into the acceptor phase. The developed method was successfully applied for the analysis of water samples.

Matched MeSH terms: Chromatography, Liquid/methods*
Global and Targeted Proteomics of Prostate Cancer Cell Secretome: Combination of 2-Dimensional Image-Converted Analysis of Liquid Chromatography and Mass Spectrometry and In Silico Selection Selected Reaction Monitoring Analysis

Nurdin A, Hoshi Y, Yoneyama T, Miyauchi E, Tachikawa M, Watanabe M, et al.

J Pharm Sci, 2016 Nov;105(11):3440-3452.
PMID: 27665127 DOI: 10.1016/j.xphs.2016.08.013

Prostate-specific antigen is currently the only protein biomarker routinely used as a diagnostic tool for early detection and treatment monitoring of prostate cancer. However, it remains questionable whether prostate-specific antigen-based screening can sensitively and selectively identify the presence and progression status of primary and metastatic prostate cancers. Hence, the purpose of this study was to identify potential biomarker candidates in the secretome of primary and metastatic prostate cancer cells by using a combination of global and targeted proteomics. Quantitative comparisons among secretome proteins derived from androgen-responsive primary cancer cells (P-22Rv1), androgen-irresponsive bone metastatic cancer cells (M-PC-3), and noncancerous prostate cells (N-PNT2) were performed using 2-dimensional image-converted analysis of liquid chromatography and mass spectrometry followed by in silico selection selected reaction monitoring analysis. Mediator of RNA polymerase II transcription subunit 13-like, insulin-like growth factor-binding protein 2, and hepatocyte growth factor were identified as highly secreted proteins from P-22Rv1 cells compared with N-PNT2 cells. Prostate-associated microseminoprotein, proactivator polypeptide, collagen-α-1 (VI) chain, and neuropilin-1 were identified as predominantly secreted proteins in M-PC-3 cells compared with N-PNT2 cells. These proteins in biological fluids are considered to be candidate biomarkers of primary and/or metastatic prostate cancer.

Matched MeSH terms: Chromatography, Liquid/methods
Liquid chromatography-tandem mass spectroscopic method for the determination of zerumbone in human plasma and its application to pharmacokinetics

Eid EE, Abdul AB, Rasedee A, Suliman FE, Sukari MA, Fatah SA

J Mass Spectrom, 2011 Aug;46(8):772-81.
PMID: 21834015 DOI: 10.1002/jms.1942

A rapid, sensitive, specific and selective LC-MS/MS method for the determination of zerumbone (ZER) in human plasma using 2,4-diamino-6-(4-methoxyphenyl)-1,3,5-triazine (DMTZ) as an internal standard (IS) has been developed and validated. ZER was chromatographed on C8 column using a mobile phase of acetonitrile/water (80:20, v/v) at a flow rate of 0.25 ml min(-1) . Quantitation was achieved using ESI+ interface, employing multiple reaction monitoring (MRM) mode at m/z 219 > 81 and 218 > 134 for ZER and IS, respectively. The calibration standards were linear over a range of 5-3000 ng ml(-1) (r(2)=0.9994) with an LLOQ of 5 ng ml(-1) (RSD %; 11.4% and bias%; 9.5%). Intra- and inter-day precision of ZER assay ranged from 0.18 to 3.56% with accuracy (bias) that varied between -5.09 and 4.3%, demonstrating good precision and accuracy. Recoveries of ZER and the IS from human plasma were above 85%. The developed method was validated for the determination of ZER in rat plasma. Linearity, stability of ZER and the ME on rat plasma were discussed. The applicability of the developed method was demonstrated by measuring ZER in rat plasma samples following intravenous and intraperitoneal administration of ZER prepared in hydroxypropyl-β-cyclodextrin (HPβCD) and sodium carboxymethyl cellulose (CMC), respectively, in 20 mg kg(-1) and this study indicated a clear significant difference (p<0.05) in pharmacokinetic parameters of ZER in ZER/HPβCD complex compared with ZER in CMC preparation.

Matched MeSH terms: Chromatography, Liquid/methods*

Filters

Please provide feedback to Administrator (afdal@afpm.org.my)

External Links