Daughter scan

The most common modes of operation for ms/ms systems include daughter scan, parent ion scan, neutral loss scan, and selected reaction monitoring. The mode chosen depends on the information required. Stmctural identification is generally obtained using daughter or parent ion scan. The mass analyzers commonly used in tandem systems include quadmpole, magnetic-sector, electric-sector, time-of-flight, and ion cyclotron resonance. Some instmments add a third analyzer such as the triple quadmpole ms (27). 

The first scanning mode consists of selecting an ion with a chosen m/z ratio with the first spectrometer. This ion collides inside the central quadrupole and reacts or fragments. The reaction products are analysed by the second mass spectrometer. This is a fragment ion scan or product ion scan . This method used to be called a daughter scan . 

Extraction, SEC or SPE Cl8 Column ArHjO + O.OSMFA B ACN + 0.05M FA (0.002M ammonium formate) (Gradient) ESI, positive Single/Triple quadrupole Scan, SIM and daughter scan MC-LR,-RR,-YR NR NR 2001 [127]... 

A) Daughter scan B) Parent scan C) Neutral loss scan D) Reaction monitoring... 

ESI Ar25 positive ion ESI, product daughter) scan of nVz 760 with Ar as collision gas at 25 V offset using a triple-stage quadmpole... 

Although daughter scans are most commonly used in the MS-MS applications, parent scans yield the most interference-free biomarker distributions. In a parent scan mode, second-stage MS is used as a filter to allow selected ions characteristic to biomarkers to fly through while first-stage MS is scanned to record the molecular ions that produce the selected ions. Only biomarker compounds that can yield both the molecular and characteristic fragment ions are... 

Product scan (daughter scan) Pass only the precursor ion (/n/z)j in Q1 (RF/DC parked), coUisionally activate and fragment (m/z)i inside the collision cell (q2, RF only), and scan Q3 (RF/DC amplitude scanned) to produce a mass spectmm of the product ions and unfragmented (m/z)i. 

Fixed-product ion scans (sector instruments). High-voltage scan or linked scan at constant B /E. Both techniques give a spectrum of all precursor (parent) ions that fragment to yield a preselected product (daughter) ion. 

Constant neutral loss (or fixed neutral fragment) scans. The linked scan at constant B[1 -(E/Eg)] /E gives a spectrum of all product (daughter) ions that have been formed by loss of a preselected neutral fragment from any precursor (parent) ions. 

Medem was already waiting impatiently, along with his wife, daughter, and two sons, scanning the low horizon for sight of the expedition. 

The following examples illustrate the range of apphcations of LC/MS for trace analysis of explosives ESI-LC/MS/MS-CID fragmentation processes of a series of nitroaromatic, nitramine and nitrate ester explosives were studied in the negative-ion mode using daughter-ion, parent-ion and neutral loss scans [14]. Table 1 shows the CID daughter ions in ESI-MS/MS of TNT. 

Since both ESP and ISP produce quasimolecular ions, more sophisticated techniques, such as LC-MS-MS are required to obtain diagnostic fragment ions and, thus, analyte structure elucidation (117, 118). Identification can often be achieved by using daughter ion MS-MS scans and collisionally induced dissociation (CID), most commonly on a triple quadrupole MS in this way, dissociation of the quasimolecular ion occurs and diagnostic structural information can be obtained (119). 

Daughter ion scan. In this mode, an ion is selected with the first mass filter and enters the collision cell where it collides with a target gas (argon or N2). The fragments formed in the collision cell are then analysed by scanning the second mass analyser. In this way, the mass spectrum of a selected ion is obtained. 

Fig. 12. In this scanning electron micrograph of the final stage of cell division both daughter cells are more or less spherical and adhering to the surface by filopodia. After disrupting the connecting filaments they will flatten and start migration over the surface with velocities of several micrometers per hour...

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