• Mass Spectrometry Letters
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• v.4 no.4
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• pp.59-66
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• 2013

A metabolomics study was conducted to identify urinary biomarkers for breast cancer, using gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS), analyzed by principal components analysis (PCA) as well as a partial least squares-discriminant analysis (PLS-DA) for a metabolic pattern analysis. To find potential biomarkers, urine samples were collected from before- and after-mastectomy of breast cancer patients and healthy controls. Androgens, corticoids, estrogens, nucleosides, and polyols were quantitatively measured and urinary metabolic profiles were constructed through PCA and PLS-DA. The possible biomarkers were discriminated from quantified targeted metabolites with a metabolic pattern analysis and subsequent screening. We identified two biomarkers for breast cancer in urine, ${\beta}$-cortol and 5-methyl-2-deoxycytidine, which were categorized at significant levels in a student t-test (p-value < 0.05). The concentrations of these metabolites in breast cancer patients significantly increased relative to those of controls and patients after mastectomy. Biomarkers identified in this study were highly related to metabolites causing oxidative DNA damage in the endogenous metabolism. These biomarkers are not only useful for diagnostics and patient stratification but can be mapped on a biochemical chart to identify the corresponding enzyme for target identification via metabolomics.

• Analytical Science and Technology
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• v.30 no.2
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• pp.102-111
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• 2017

Here we reported a methodology for identification of triacylglycerols (TAGs) and diacylglycerols (DAGs) in coix seed by preparative thin layer chromatography (prep-TLC) and non-aqueous reversed-phase liquid chromatography (NARP LC)-atmospheric pressure chemical ionization (APCI) tandem mass spectrometry (MS/MS). Lipid components were extracted from coix seed by reflux extraction using n-hexane for 3 hr. TAGs and DAGs in coix seed extract were effectively purified and isolated from matrix interferences by prep-TLC and then analyzed by LC-APCI-MS and MS/MS for identification. TAGs were effectively identified taking into consideration of their LC retention behavior, APCI-MS spectra patterns, and MS/MS spectra of $[DAG]^+$ ions. In MS/MS spectra of TAGs, diacylglycerol-like fragment $[DAG]^+$ ions were useful to identify TAGs with isobaric fragment ions. Based on an established method, 27 TAGs and 8 DAGs were identified in coix seed extract. Among them, 15 TAGs and 8 DAGs were for the first time observed in coix seed. Interestingly, some of TAGs isolated by prep-TLC were partly converted into DAGs through probably photolysis process during storing in room temperature. Thus, degradation phenomenon of TAGs should be considered in the quality evaluation and nutritional property of coix seed. LC-APCI-MS/MS combined with prep-TLC will be practical method for precise TAG and DAG analysis of other herbal plants.

• Analytical Science and Technology
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• v.21 no.6
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• pp.518-525
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• 2008

Mandipropamid is a new mandelamide-type fungicide to control foliar Oomycete pathogens in some vegetables. An analytical method was developed to determine mandipropamid residues in agricultural commodities using high-performance liquid chromatography (HPLC) and liquid chromatography/mass spectrometry (LC/MS). Mandipropamid was extracted with methanol from grape, tomato, green pepper, Chinese cabbage and potato samples. The extract was diluted with saturated sodium chloride solution and distilled water, and dichloromethane partition was followed to recover the mandipropamid from the aqueous phase. Florisil column chromatography was employed to further remove interfering co-extractives prior to HPLC analysis. Reverse-phased HPLC was successfully applied to determine mandipropamid in sample extracts with the detection at its ${\lambda}_{max}$ (223 nm). Overall recoveries of mandipropamid from fortified samples averaged $99.8{\pm}1.7$ (n=6), $89.3{\pm}5.3$ (n=6), $98.7{\pm}2.2$ (n=6), $99.7{\pm}6.8$ (n=6) and $91.1{\pm}3.1$ (n=6) for grape, tomato, green pepper, Chinese cabbage and potato, respectively. Limit of quantification of the method was 0.02~0.04 mg/kg for all samples. A LC/mass spectrometry with selected-ion monitoring was also provided to confirm the suspected residue. The proposed method was reproducible and sensitive enough to determine the terminal residue of mandipropamid in agricultural commodities.

• Environmental Mutagens and Carcinogens
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• v.26 no.1
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• pp.25-29
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• 2006

Antimicrobial peptides (AMPs) play an important role in this response by rapidly killing invading microorganisms. In this study antimicrobial peptide has been isolated from acidified whole body extract of a bivalve mollusk, the marine mussel (Mytilus coruscus). This peptide purified to homogeneity by gel-filtration and reversed-phase high performance liquid chromatography. The molecular weight was 1464.92 Da, determined by MALDI-TOF Mass spectrometry. In addition to growth inhibition of Escherichia coli D31.

• Mass Spectrometry Letters
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• v.7 no.1
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• pp.12-15
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• 2016

Results of free and bound myo-inositol in infant formula (IF) are presented. Inositol was analyzed by HILIC ultra-performance liquid chromatography coupled with mass spectrometer. The levels of free myo-inositol in 27 Australian and 4 EU originated IF samples were 300-600 mg/kg of powder or 1.6-3.1 mg/100 kJ. The amount of bound inositol in lipid fraction of IF was, on average, 10% of free myo-inositol.

• Korean Journal of Environmental Agriculture
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• v.30 no.4
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• pp.432-439
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• 2011

BACKGROUND: An official analytical method was developed to determine etofenprox residues in agricultural commodities using high-performance liquid chromatography (HPLC). METHODS AND RESULTS: The etofenprox residue was extracted with acetone from representative samples of five raw products which comprised rice grain, apple, mandarin, cabbage, and soybean. The extract was then serially purified by liquid-liquid partition and Florisil column chromatography. For rice and soybean samples, acetonitrile/n-hexane partition was additionally coupled to remove nonpolar lipids. Reversed phase HPLC using an octadecylsilyl column was successfully applied to separate etofenprox from co-extractives. Intact etofenprox was sensitively detected by ultraviolet absorption at 225 nm. Recovery experiment at the quantitation limit validated that the proposed method could apparently determine the etofenprox residue at 0.02 mg/kg. Mean recoveries from five crop samples fortified at three levels in triplicate were in the range of 93.6~106.4%. Relative standard deviations of the analytical method were all less than 10%, irrespective of crop types. A selected-ion monitoring LC/mass spectrometry with positive atmospheric-pressure chemical ionization was also provided to confirm the suspected residue. CONCLUSION(s): The proposed method is simple, rapid and sensitive enough to be employed in routine inspection or monitoring of agricultural products for the etofenprox residue.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.223.2-223.2
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• 2003

A rapid, sensitive and selective liquid chromatography-tandem mass spectrometric (LC/MS/MS) method for the determination of eupatilin in human plasma was developed. Eupatilin and internal standard, (S)-[N-3-(4-(2-(1-methyl-5-tetrazolyl)-pyridine-5-y1)- 3-fluorophenyl)-2-oxo-5-oxazolidinyl]methyl acetamide (DA-7867) were extracted from human plasma by liquid-liquid extraction and analyzed on a phenyl-hexyl column with the mobile phase of acetonitrile-ammonium formate (10 mM, pH 3.0) (60:40, v/v). (omitted)

• Advances in environmental research
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• v.2 no.3
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• pp.179-202
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• 2013

Bisphenol A and other alkylphenols are widely used in plastic and other industrial consumer products. Release of these compounds into the aquatic environment during their manufacture, use and disposal has been a great scientific and public concern due to their toxicity at high concentrations and endocrine disrupting effects at low concentration on aquatic wildlife and human beings. This paper reviews the published data and researches on the environmental occurrence, distribution, health effects and analytical techniques of bisphenol A and alkylphenols. The aim is to provide an overview of the current understanding about bisphenol A and alkylphenols in the environment and the difficulties faced today in order to establish standard and systematic environmental analysis and assessment process for these endocrine disruptor compounds.

• Analytical Science and Technology
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• v.19 no.6
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• pp.519-528
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• 2006

An analytical method for the determination of thyroid hormones in urine samples has been studied by using solid-phase extraction and high-performance liquid chromatography/diode array detector/electro-spray mass spectrometry. Seven thyroid hormones were successfully separated by gradient elution on the reverse phase Hypersil ODS column (4.6 mm I.D., 100 mm length, particle size $5{\mu}m$) with ammonium formate buffer and acetonitrile, and UV spectra and mass fragment could be confirmed. The extraction recoveries of thyroid hormones in the urine samples (pH 3) were in the range of 89.0-113.1% with solid-phase extraction by C18, followed by elution with 4 ml of methanol/ammonium hydroxide (9 : 1). The calibration curves showed good linearity with the correlation coefficients ($r^2$) varying from 0.992 to 0.998 and the detection limits of all analytes were obtained in the range of 2-4 ng/ml (3.8-13.0 pmol/ml).

• BMB Reports
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• v.43 no.7
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• pp.506-511
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• 2010

The levels of salivary cortisol and cortisone in Korean adults were measured for the first time using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The salivary cortisol and cortisone were separated within 10 min. The regression coefficients (r) of the calibration curves were greater than 0.999 for the two steroids. The limits of quantitation (LOQ) were 0.2 ng/ml for cortisol and 1 ng/ml for cortisone. The intra-day precisions of the assay were <3.9% and 8.6% for cortisol and cortisone respectively, and the inter-day precisions were <1.9% and 4.3% for cortisol and cortisone, respectively. The salivary cortisone concentrations were approximately 4-9 times higher than those of salivary cortisol during the daytime. Diurnal rhythms, during which the cortisol and cortisone concentrations were higher in the morning than in the afternoon, were also observed. The present assay may be useful for the diagnosis of several adrenal dysfunctions in clinical biochemistry.