Yan Li, Milos Dvorak, Nantana Nuchtavorn, Pavel N. Nesterenko, Roger Stanley, Mirek Macka
Our aspiration was to design portable LC as a widely available ‘open platform’, moderate-pressure (over 100 bar), and importantly highly flexible modular system, based almost entirely on commercial off-the-shelf low-cost components. In this work, a modular portable LC has been designed, characterised and used, weighing under 2 kg (plus data acquisition). The backbone of the system was a breadboard assembled modular flexible microfluidic system (LabSmith), complemented with other off-the-shelf components, including an injection valve and on-capillary detectors, all operated through a PC. The system can accommodate six syringe pumps with 80, 20 and 5 µL syringe options, and maximum backpressures of up to ca. 150 bar, with two used for each A and B mobile phase in gradient operation and another pump for sampling and one in reserve for post-column derivatisation. The flow rate (typically 1 µL/min), which exhibited substantial pulsations due to the individual steps of the step motors driving the syringe pump, could be well dampened by using microbubbles of low-solubility inert gas (nitrogen, helium), automatically aspirated in each mobile phase draw cycle. Each of the two pairs of syringe pumps for mobile phases A and B were connected with microfluidic switching valves (two 4-port valves), and the A and B streams joined together with a Y-connector and a microfluidic pressure sensor, thus providing a system for low hold-up volume gradient formation. The mobile phase was led to a nano-LC sampling valve and to a capillary LC column. The detection was on-column (100 µm i.d. PTFE-coated fused silica) with an LED-based deep-UV-vis-NIR photometric detector, and end-column with an electrochemical detector (amperometric and/or potentiometric). The performance of the system was evaluated including the pumping accuracy, linearity of gradient formation, separation performance and sensitivity of detection. Typically analysis runs used 12-20 µL of solvent with overall reproducibility of 1 5 % and 3 6% RSD for retention times and peak area in gradient mode, respectively. Future avenues for miniaturisation of the data acquisition and system control are discussed.
In molecule optics, a matter wave of molecules is manipulated by a molecule-optical component made of external, typically radiative, fields. The molecule-optical index of refraction, n, for a nonresonant IR laser pulse focused onto a molecular beam can be obtained from the energy conservation and wave properties of molecules. Experimentally measured values of n for benzene and nitric oxide agreed well with the calculated values. Since n depends on the properties of molecules as well as those of the laser field, a molecule prism composed of the focused nonresonant laser field can separate a multi-component molecular beam into several components according to their molecule-optical refractive indices n. We obtained a chromatographic resolution of 0.90 for the spatial separation of a mixture beam of benzene and nitric oxide using a focused Nd:YAG laser pulse as a molecule prism. In addition, ways of improving the efficiency of optical forces will be discussed.
Virginia Coman,1 Mihail Simion Beldean-Galea,2 Florina Copaciu,1 Miuta Filip,1 Mihaela Vlassa1
1 Babes-Bolyai University, Raluca Ripan Institute for Research in Chemistry, 30 Fantanele Street, 400294, Cluj-Napoca, Romania
Pharmaceuticals are micropollutants belonging to the main sources of water pollution due to their relative persistence and toxicity in the water body. These compounds are used to treat human and animal diseases and come in the surface waters from the industrial production, hospitals and incompletely metabolized drugs. During the last time an increased resistance of human and animal bodies to drugs was registered that leads to some unexpected health effects. This fact is caused by the uncontrolled input of pharmaceuticals in surface waters that determined the European Union to pay a special attention to this topic. Thus the European Parliament amending the Water Framework Directive (2000/60/EC) is preoccupied to introduce some anti-inflammatory drugs, namely diclofenac and 17beta-estradiol, in the list of emerging pollutants and to establish their maximum allowable concentration in surface waters. In this work, the authors present the results of one year monitoring (July 2014-June 2015) of some classes of pharmaceuticals (nonsteroidal anti-inflammatories, hormones, antibiotics, anticancers) widely used for the human and veterinary treatments, in Tisza River and some of its tributaries on Romanian territory. The isolation of studied pharmaceuticals from water matrices was achieved by solid-phase extraction (SPE) on Strata C18-U and Strata X cartridges. The pharmaceutical analysis was performed by high performance liquid chromatography coupled with diode array detector and/or mass spectrometer. The SPE-HPLC-DAD/MS procedures were used for the determination of the target compounds in river water samples collected from the Romanian Tisza River Watershed during four seasons. The developed procedures were validated and studies of statistical significance of the obtained results were done. Among the target pharmaceuticals found in the investigated river water samples were diclofenac and ibuprofen as anti-inflammatories; estrone and 17beta-estradiol as hormones and tetracycline, doxycycline, ceftazidime and ceftriaxone as antibiotics. The monitoring results show the importance of the study of pharmaceuticals in surface waters for a better risk assessment.
Acknowledgements: This work has been performed in the frame of NATO Science for Peace 984440/2014-2017 Project.
State pollution of rivers and other surface water reservoirs in Ukraine is under the regular control of the State. This control is carried out by the Ministry of Environment, Ministry of Health, other governmental departments and agencies. In Ukraine developed an extensive regulatory documentation, which determine the procedures waters monitoring and methods of measurement. Monitoring of water quality include the following mandatory chemical parameters as pH, the presence of ammonia nitrogen, heavy metals, content of acid residues as nitrites, nitrates, chlorides, sulfates, phosphates, oxygen content, chemical, and biological oxygen demand, phenols, surfactants. The control of organic components, such as pesticides, pharmaceuticals and others, conducted in areas where there is a threat of such pollution. Chromatographic methods primarily used in this case.
Assessment of surface water pollution is carried by a combined index - an index of pollution IWP, which is calculated by the formula :
IWP = ∑(C / MAC)/n
C – actual concentration
MAC - Maximum allowable concentration
n – number of indications
By this indicator are set 5 levels of contamination: allowable, reasonable; increased; high; very high. Most of the surface waters in Ukraine have a reasonable level of pollution. A high and very high levels of surface waters pollution is determined in the south and east of Ukraine. This is due to the presence in these areas, the mining industry and intensive agriculture. In the western regions of Ukraine, in particular in the Transcarpathian region the level of surface waters contamination is allowable. These areas belong to the recreational areas and the number of enterprises which pollute the environment on this territory is insignificant.
Acknowledgements: This work has been performed in the frame of NATO Science for Peace 984440 Project.
Crude oil is the most complex mixture known to man. It has been called a supercomplex mixture –meaning that it is so complex in composition that it cannot be entirely separated (down to the detection limit) with any technique or combination of techniques. This presents a huge problem to the analytical chemist in the characterization of this multi-billion euro commodity.
Despite this limitation, an immense amount of analytical information can be gained from such samples. Ultrahigh-resolution mass spectrometry plays a major role in the molecular characterization of petroleum, a topic of great interest both in science and industry, but even with the highest resolution and mass accuracy available, there are areas where a combination of chemistry (e.g. derivatization) and/or separation (for instance, chromatography) are indispensible to increase the amount of analytical information obtainable by MS.
A separation of the analytes from matrix compounds can improve and in some cases is indispensible to enable ultrahigh resolution MS measurements, for instance by reducing the total number of ions in the mass spectrometer (eliminating ion suppression). A case illustrating this, in the analysis of ketones in a crude oil, will be discussed. If the chromatographic separation is designed carefully for the particular class of compounds, involving a group separation, structural information on the analytes can be obtained through the chromatographic step alone, as will be shown for the analysis of sulfur and nitrogen compounds. Ligand-exchange chromatography (LEC) is particularly valuable since it allows a selective interaction with the functional groups. Several LEC variations will be discussed.