Nanospray technique, mass spectrometry

Warriner, R. N., Craze, A. S., Games, D. E., and Lane, S. J. (1998). Capillary electrochromato-graphy/mass spectrometry a comparison of the sensitivity of nanospray and microspray ionization techniques. Rapid Commun. Mass Spectrom. 12, 1143-1149. 

Xie et al. [5] used vapor-deposited parylene-C to fabricate ESI tips on silicon microfluidic devices, enabling integrated liquid chromatography with mass spectrometry detection with comparable performance to conventional techniques. The drawback for these devices is the complexity involved in their fabrication, requiring many sequential photolithography steps in a clean room. However, parylene is a material with high chemical resistance and may be a useful choice for the construction of nanospray tips in future work. For example, Kameoka et al. [6] constmcted a nanospray tip comprising a parylene film sandwiched between two plastic plates (Fig. 2b). This device is relatively easy to... 

There are a number of options for analyzing a peptide mixture extracted from a gel by mass spectrometry. The most widely used techniques are MALDI-TOF, preferably with delayed extraction, and ESI with a triple-quadrupole analyzer or a combination of quadrupole and TOF analyzers. The combination of ESI with an ion trap is also of great interest due to its sensitivity and the possibility of performing structural studies by MS". Downsizing of the electrospray capillary such as in the nanospray technique results in another gain in sensitivity and an extension of the measuring time, which is important to optimize fragmentation conditions. 

Two factors favor the use of nanoelectrospray ionization for coupling microfluidic devices to mass spectrometers. The first is the similarity between the conventional puUed-glass capillary tips and the nanospray nozzles developed for microdevices discussed in the previous section the second springs from the linear geometry of nricrofluidic channels. Thus, we believe that nanospray ionization techniques are the most likely to be used for tbe construction of robust interfaces between microfluidics and mass spectrometry for most applications in tbe future [16]. 

In order to definitively establish that two fiber samples are of identical origin, it is i.a. necessary to demonstrate that their dye components are identical, and that those dyes are present in the same proportions in each fiber. The qualitative comparison is necessary because fiber manufacturers often use identical dyes in different proportions to create differently colored fibers. The combination of electrospray ionization mass spectrometry and tandem mass spectrometry has been shown to provide both the qualitative and quantitative information required such comparisons. The technique is sufficiently specific and sensitive to allow comparison of two fibers, one of which is available lengths of as little as one millimeter. The use of more sophisticated electrospray techniques (microspray and nanospray) would further enhance both specificity and sensitivity. 

One of the major attractions of ESI is its ability to serve as an interface between liquid chromatography and mass spectrometry. There are currently a number of low-flow HPLC systems on the market that are compatible with electrospray, microspray, and nanospray sources. Capillary HPLC systems are interfaced with electrospray conducted in the pL/min flow regime, while nanoflow systems can accommodate nL/min flow rates. When electrospray is coupled with conventional HPLC, it is necessary to accommodate a higher sample flow rate ( 0.1—2mL/min) than normal electrospray can tolerate. To facilitate operation at these higher flow rates, a technique called pneumatically assisted electrospray or ion spray is employed, in which sample nebulization by aflow of gas is used to stimulate a more... 

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