Isotopic Composition of C, N, and S as an Indicator of Endometrial Cancer.

Objectives: The metabolic pathway of cancerous tissue differs from healthy tissue, leading to the unique isotopic composition of stable isotopes at their natural abundance. We have studied if these changes can be developed into diagnostic or prognostic tools in the case of endometrial cancer.

Methods: Measurements of stable isotope ratios were performed using isotope ratio mass spectrometry for nitrogen, carbon, and sulfur isotopic assessment.

Hydrophilic interaction liquid chromatography based method for simultaneous determination of purines and their derivatives in food spices.

This work presents method for separation and quantification of adenine, guanine, xanthine, hypoxanthine, uric acid, and creatinine in food spices using hydrophilic interaction liquid chromatography with UV detection. Optimized conditions allowed separation with mobile phases containing acetonitrile and additives ammonium acetate (90:10, v/v, pH 6.1) or formate (90:10, v/v, pH 3.

A novel simultaneous isotope dilution strategy as a powerful tool in the two-track certification process of trace metal mass fractions: a case study of mercury, cadmium and lead in soil and sediment materials.

An analytical methodology based on isotope dilution (ID) principles was developed to establish the reference procedure for the simultaneous assignation of aqua regia extractable and total mass fractions of Hg, Cd, and Pb in soil and sediment matrix samples. The 'twin sample-spike blends' were prepared under close to the exact matching conditions, resulting in almost identical mass ratios of the spike to the sample in the blends, which followed either the aqua regia extraction method or total digestion procedure. The isotope ratios in 'twin-blends' were measured by inductively coupled plasma mass spectrometry (ICP-MS).

Assignation of inorganic mercury and methylmercury mass fractions in a soil matrix certified reference material by two analytical methodologies based on species-specific isotope dilution mass spectrometry and chromatographic separation.

Assignment of inorganic mercury and methyl mercury mass fractions at an ultratrace level in soil certified reference material EnvCRM 03 with a complex matrix composition was undertaken. Inorganic mercury and methyl mercury contents by species-specific isotope dilution inductively coupled plasma mass spectrometry with on-line high-performance liquid chromatography or with classical off-line chromatography were established. Different extraction protocols: sequential extraction ((1) H SO /KBr/CuSO ; (2) dichloromethane; (3) Na S O ) or one-step extraction (diluted HCl) in solid-liquid systems were verified.

Insights into Primary Ion Exchange between Ion-Selective Membranes and Solution. From Altering Natural Isotope Ratios to Isotope Dilution Inductively Coupled Plasma Mass Spectrometry Studies.

Although ion-selective electrodes have been routinely used for decades now, there are still gaps in experimental evidence regarding how these sensors operate. This especially applies to the exchange of primary ions occurring for systems already containing analyte ions from the pretreatment step. Herein, for the first time, we present an insight into this process looking at the effect of altered ratios of naturally occurring analyte isotopes and achieving isotopic equilibrium.

Simultaneous speciation analysis of mercury in marine origin samples by high performance liquid chromatography and species - specific isotope dilution inductively coupled plasma mass spectrometry.

Species-specific isotope dilution inductively coupled plasma quadrupole mass spectrometry reference method and high-performance liquid chromatography were applied for simultaneous determination of mercury species in marine samples. Different extraction protocols for mercury species were tested and evaluated. It was found that after exposure to microwave energy the inorganic mercury (iHg) and methyl mercury (MeHg) can be completely extracted from marine biota sample by 4.

Cold vapour matrix-independent generation and isotope dilution inductively coupled plasma mass spectrometry for reference measurements of Hg in marine environmental samples.

The analytical procedure for reference measurements of Hg in marine environmental samples based on cold vapour generation (CVG) inductively coupled plasma quadrupole mass spectrometry (ICP-QMS) and isotope dilution calibration strategy (ID) is described in the present study. The procedure was applied on different matrices and varying mass fractions for mercury in oyster, marine sediment and costal seawater samples. The use of CVG for sample introduction resulted in sensitivity enhancement, reduction of blank levels, minimization of matrix interferences and the elimination of memory effects.

Direct determination of δ Ca isotope ratio by ion chromatography/low-resolution multicollector ICPMS.

High-precision on-line procedure for measurement of calcium isotopic ratio by coupling ion chromatography to multicollector inductively coupled plasma mass spectrometry was developed. Calcium separation from the sample matrix was achieved on an ion chromatography column-IonPac CS16-ID 3 mm connected with CERS 500 2 mm suppressor and followed by multicollector inductively coupled plasma mass spectrometry calcium isotopic ratio determination. Dry plasma mode was used with Aridus II desolvation system.

High precision direct analysis of magnesium isotope ratio by ion chromatography/multicollector-ICPMS using wet and dry plasma conditions.

In this work the applicability of Ion Chromatography (IC) coupled to Multicollector Inductively Coupled Plasma Mass Spectrometry (MC-ICPMS) for on-line magnesium isotope ratio analysis was explored. Various instrumental setups were employed to enable continuous magnesium separation from the sample matrix by IC followed by MC-ICPMS. The performance of two separation columns IonPac CS16 (ID 5mm or ID 3mm) connected with appropriate CERS 500 suppressors (4mm or 2mm) using dry and wet plasma conditions was compared.