Piezoelectric Micropumps and Their Biomedical Applications

Small, lightweight and powerful, the piezoelectric micropumps are perfect for portable, battery-operated medical devices and diagnostic applications. Meanwhile, excellent gas pumping capability renders the pump opportunities in the environmental and industrial hygiene applications.  This micropump can be used to circulate media or continuously supply fresh media for cell culturing or tissue engineering with greatly reduced risk of contamination over time. The continuously adjustable flow rates are able to actively optimize the media conditions, and the virtually steady flow can minimize the perturbation to cells. 

Analysis of Organic Acids with Ultisil OAA Column

Organic acids refer to organic compounds with acidic properties. The most common ones are associated with functional groups of carboxyl (-COOH), sulfonic group (-SO3H), sulfinic group (-SO2H), such as malic acid, tartaric acid, oxalic acid, formic acid, etc. Organic acids have wide applications in oil and gas well stimulation treatments, food preservation, nutrition, animal feed and biological system. 

Reversed phase high performance liquid chromatography (HPLC) is the most widely used method for the separation and analysis of organic acids. Usually, acidic aqueous mobile phase is used to prevent the dissociation of organic acids and improve the retention in the hydrophobic column. 

Analysis of Amino Acids with Ultisil Amino Acids Plus HPLC Column

Amino acids are the basic constituents of proteins and also intermediates in metabolic pathways. Analysis of amino acids is high demanded in the pharmaceutical research and food industry for protein characterization, cell culture monitoring, and nutritional analysis of foods and feeds. Reverse phase HPLC was widely used for the separation of the amino acids. However, direct HPLC analysis of amino acids has some challenges：

• Most of amino acids are very polar due to their carboxyl group(-COOH) and amino group (NH2). This results in poor retention in Conventional reversed-phase conditions.
• Most of the amino acids and their substituent groups have poor UV absorbance and poor sensitivity in detection. 

Liquid Chromatography-Mass Spectrometer (LC-MS) Flow Splitting and Sample Injection

Capillary Liquid chromatography/mass spectrometry (LC/MS) has been extensively used in life science for the analysis of peptides and proteins, especially in proteomics area.  Because it shows higher resolution and sensitivity over conventional LC.  Capillary LC utilizes columns with smaller inner diameters (< 0.5 mm) than conventional LC and flow rates from some few µL /min down to the nL/min or even pL/min range.   Smaller ID columns produce higher and narrower chromatographic peaks for a fixed amount of injected material as the same amount of analyte elutes at a higher concentration as well as a better separation efficiency.  The peak height is inversely proportional to the cross-sectional area of the column.  Meanwhile the lower solvent flow rate provides higher ionization and sampling efficiency allowing a higher percentage of analytes in the solution phase to be transmitted to the MS detector.  Combination of these effects provide better detection limit for mass spectrometry.