Simultaneous determination of delta(33) SV-CDT and delta S-34(V-CDT) using masses 48, 49 and 50 on a continuous flow isotope ratio mass spectrometer

A new, fast, continuous flow technique is described for the simultaneous determination of 633 S and delta(34)S using SO masses 48, 49 and 50. Analysis time is similar to5min/sample with measurement precision and accuracy better than +/-0.3parts per thousand. This technique, which has been set up using IAEA Ag2S standards S-1, S-2 and S-3, allows for the fast determination of mass-dependent or mass-independent fractionation (MIF) effects in sulfide, organic sulfur samples and possibly sulfate. Small sample sizes can be analysed directly, without chemical pre-treatment. Robustness of the technique for natural versus artificial standards was demonstrated by analysis of a Canon Diablo troilite, which gave a delta(33)S of 0.04parts per thousand and a delta(34)S of -0.06parts per thousand compared to the values obtained for S-1 of 0.07parts per thousand and -0.20parts per thousand, respectively. Two pyrite samples from a banded-iron formation from the 3710 Ma Isua Greenstone Belt were analysed using this technique and yielded MIF (Delta(33)S of 2.45 and 3.31parts per thousand) comparable to pyrite previously analysed by secondary ion probe. Copyright (C) 2004 John Wiley Sons, Ltd.

Simultaneous determination of morphine, oxycodone, morphine-3-glucuronide, and noroxycodone concentrations in rat serum by high performance liquid chromatography-electrospray ionization-tandem mass spectrometry

An assay using high performance liquid chromatography (HPLC)-electrospray ionization-tandem mass spectrometry (ESI-MS-MS) was developed for simultaneously determining concentrations of morphine, oxycodone, morphine-3-glucuronide, and noroxycodone, in 50 mul samples of rat serum. Deuterated (d(3)) analogues of each compound were used as internal standards. Samples were treated with acetonitrile to precipitate plasma proteins: acetonitrile was removed from the supernatant by centrifugal evaporation before analysis. Limits of quantitation (ng/ml) and their between-day accuracy and precision (%deviation and %CV) were-morphine, 3.8 (4.3% and 7.6%); morphine-3-glucuronide, 5.0 (4.5% and 2.9%); oxycodone, 4.5 (0.4% and 9.3%); noroxycodone, 5.0 (8.5% and 4.6%). (C) 2004 Elsevier B.V. All rights reserved.

The current account, fiscal policy, and medium-run income determination

This article presents a new framework for analyzing the simultaneous determination of current account imbalances and the path of national income. Using standard macroeconomic behavioral relationships, it first examines how and why current account deficits matter by investigating links between domestic consumption, government spending, output, saving, investment, interest rates, and capital flows. Central to the model is the distinction between aggregate output and expenditure that enables dissection of the effects of discretionary fiscal change on the current account and national income. The framework yields results relevant to the twin deficits hypothesis that are contrary to those of standard models.

Simultaneous liquid chromatographic determination of doxorubicin and its major metabolite doxorubicinol in parrot plasma

A new microscale method is reported for the determination of doxorubicin and its active metabolite, doxorubicinol, in parrot plasma. Sample workup involved acetonitrile protein precipitation, ethyl acetate extraction, followed by back extraction into HCl. Separations were achieved on a phenyl-hexyl column at 30 degrees C using acetonitrile (17%, v/v) in 0.01 M orthophosphoric acid (83%, v/v) delivered via a linear flow program. Fluorometric detection wavelengths were 235 nm (excitation) and 550 nm (emission). Calibration plots were linear (1 2 > 0.999), and recoveries were 71-87% from 20 to 400 ng/mL. Assay imprecision was