Search

This study aimed to measure phytoestrogen contents in health functional foods (HFFs) to alleviate menopausal symptoms that are commercially available in South Korea. A sensitive and selective method using gas chromatography–mass spectrometry (GC-MS) for the monitoring of 21 phytoestrogens was developed and fully validated. Phytoestrogens were extracted by liquid–liquid extraction using methyl tert-butylether as the solvent. Food samples were enzymatically hydrolyzed with β-glucuronidase/arylsulfatase. Before GC-MS, the analytes were derivatized to their trimethylsilyl derivatives by incubation with N,O-bis(trimethylsilyl)trifluoroacetamide with 1% trimethylchlorosilane for 30 min at 80°C. The calibration curves showed good linearity (r 2 > 0.99) in the range of interest for each analyte. The limits of detection and quantification of the 21 phytoestrogens were in the ranges of 0.5–20 and 1–50 ng/mL, respectively. The intra- and inter-day precisions were all below 15.7%. These multivariate procedures were efficient in determining the optimal conditions using peak heights as responses.

Ultrahigh performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLCESI-MS/MS) provides a high-speed method to screen a large number of samples for small molecules with specific properties. In this study, UPLC-ESI-MS/MS with multiple reaction monitoring (MRM) was employed to screen urinary phospholipid (PL) content for biomarkers of prostate cancer. From lists of urinary PLs structurally identified using nanoflow LC-ESI-MS/MS, 52 PL species were selected for quantitative analysis in urine samples between 22 cancer-free urologic patients as controls and 45 prostate cancer patients. Statistical treatment of data by receiver operating characteristic (ROC) analysis yielded 14 PL species that differed significantly in relative concentrations (area under curve (AUC) > 0.8) between the two groups. Among PLs present at higher levels in prostate cancer urine, phosphatidylcholines (PCs) and phosphatidylinositols (PIs) constituted the major head group PLs (3 PCs and 7 PIs). For technical reasons, PL species of low abundance may be underrepresented in data from UPLC-ESI-MS/MS performed in MRM mode. However, the proposed method enables the rapid screening of large numbers of plasma or urine samples in the search for biomarkers of human disease.

In this study, total mercury and methyl mercury in whole blood of Korean was analyzed so as to investigate the correlation between total mercury (T-Hg) and methyl mercury (Me-Hg). 4000 whole blood samples were divided in four groups, according to T-Hg concentration in percentile: group I (p25-p50), group II (p50-p75), group III (p75-p95) and group IV (p95-p100). 100 samples were randomly selected from the each group, and Me-Hg concentration was measured. T-Hg concentration in whole blood was analyzed using a Direct Mercury Analyzer-80 and obtained limit of detection (LOD) was 0.2 µgL �1 . Me-Hg concentration was analyzed with ethylate derivatization using headspace-gas chromatography-mass spectrometry, and obtained LOD of methyl mercury was 0.5 µgL �1 . The geometric means of T-Hg and Me-Hg were 6.35 µgL �1 and 4.44 µgL �1 , respectively, and 71.91% of T-Hg was presented as Me-Hg.

Spherical porous silica supports modified with titanium or zirconium alkoxides were prepared, and allyl groupswere chemically attached to the titanized or zirconi zed silica supports, and the product was cross-polymerizedwith a double bond containing cellulose derivative to yield new CSPs (chiral stationary phases). Magic anglespinning

Sodium hyaluronate (NaHA), water soluble polymer having ultra-high molecular weight, is characterized by using on-line frit inlet asymmetrical flow field-flow fractionation (FI-AFlFFF) and multiangle light scattering (MALS). This study demonstrates the capability of power programming FI-AFlFFF for the separation of NaHA and the applicability of FI-AFlFFF with MALS for the characterization of molecular weight distribution and their structural information. Since sample injection and relaxation in FI-AFlFFF are achieved by using hydrodynamic relaxation, separation of high molecular weight polymers can be achieved smoothly without halting the separation flow. Experiments are carried out with the two different NaHA products (a raw NaHA sample and a thermally degraded NaHA product) and molecular weight distribution and conformations in solution are determined. Influence of sample filtration on the change of molecular weight distribution is also discussed.