Electro-optic solution to overcome the transient regime of a cavity dumped UV laser source?

International audienc

EO solution to overcome the transient regime of a “cavity dumped” UV source, or how to work in chopped mode outside the transient regime?

The "cavity dumped" laser architecture is a very efficient solution for having a high-efficiency pulsed laser source with a shorter pulse duration than a classic Q-Switch laser architecture. This solution makes it possible to obtain laser beams of almost constant pulse duration independently of the repetition rate and the pumping rate and to obtain very good conversion efficiency at 2w and 3w. Unfortunately, this architecture suffers from a handicap with a duration of the transient regime that can exceed ten milliseconds. The very long duration of this transient state makes this architecture incompatible with inherently transient applications such as marking or laser micro-machining. We propose here an electro-optical solution to decorrelate the transient state specific to the CD architecture and that of introduced by the application

In situ carbon and oxygen isotopes measurements in carbonates by fiber coupled laser diode-induced calcination

Stable isotopic compositions of carbon and oxygen (δ13C et δ18O) measured from carbonates are used in geology to reconstruct paleotemperatures and to learn about the evolution of the biogeochemical carbon cycle. The standard technique used since the middle of the XXth century [1] to measure isotopic ratios is based on a wet chemical protocol which CO2 is evolved from the acidic dissolution of carbonates followed by quantification of CO2 molecules isotopologues using mass spectrometer or infrared spectroscopy. This is a lengthy protocol that necessitate to manipulate acid solution and numerous gas phases purification steps before isotopic measurements. Our new preparation technique aims at offering an alternative to the wet chemical preparation of the samples by using a direct extraction of CO2 via a laser-induced calcination process. In addition to save time, this method allows to consider spatially resolved and automated in-situ measurements and does not necessitate further purification steps of the evolved CO2 during calcination

A rapid, automatic and accurate assay for quantifying temocillin in human serum and CSF using turbulent flow liquid chromatography coupled to high‐resolution mass spectrometry. Clinical application

International audienceTemocillin is a β-lactamase-resistant penicillin used for the treatment of multiple drug-resistant Gram-negative bacteria. To maximize efficacy and avoid adverse effects, the dose regimen has to be quickly adjusted to the clinical situations. This necessitates the development of a rapid, reliable and accurate analytical method. Temocillin and the stable isotopically labeled internal standard ([13 C6 ]-amoxicillin) were extracted from either serum or cerebrospinal fluid by a turbulent flow liquid chromatographic method and eluted onto an octadecyl-silica phase with polar endcapping. Mass spectrometry was conducted using an exact mass determination method by electrospray positive ionization high-resolution mass spectrometry. The LLOQ and ULOQ of the present method were determined to be 0.4 and 200 μg/ml for serum and cerebrospinal fluid samples, respectively. The total analysis time was <7 min. The recovery ranged from 87.7 to 120.8%. Intra- and inter-day precision and trueness were tested at four concentration levels: 0.4, 8, 40 and 160 μg/ml. Values were 6.33 ± 1.53, 8.8 ± 1.3, 8.8 ± 0.36 and 2.1 ± 0.76%, and 5.0 ± 0.54, 9.9 ± 1.0, 5.8 ± 1.6 and 0.1 ± 1.1%, for inter- and intra-day analysis, respectively. Temocillin was found to be stable under all relevant laboratory conditions. The method was cross-validated with a microbiological assay. This method is suitable for accurate measurement of temocillin concentration in small volumes of serum or cerebrospinal fluid. Thanks to the online extraction procedure, the overall analytical time is compatible with high-throughput analysis for clinical application