Accessioning sample

To obtain information on the noble gas state in the mantle, it is necessary to analyze mantle-derived materials that have trapped mantle noble gases. Accessible samples include volcanic rocks, volcanic gases, mantle xenoliths, and diamonds. Among various mantle-derived materials, submarine volcanic rocks are particularly useful because of their wide occurrence and their relatively large (for mantle samples) amounts of trapped noble gases. So far, information has been obtained mainly from... 

The cost per sample of NAA analysis is high, involving additional personnel and reactor, and detector and processing systems. Additionally, with NAA, reactor accessibility, sample workup and analysis do not lend themselves to rapid throughput, especially where a heavy case load is involved. Reactor accessibility is limited, posing still further delays. 

Cosmic rays represent one of the three direcdy accessible samples of matter from outside our solar system. Another is interstellar dust that drifts into the solar system. The third is the presolar grains that have survived the formation of the solar system and are found in meteorites. 

Fig. 44. Cast iron works autoclave with steam heating. Capacity is 1400 liters maximum pressure, 25 atm. The stirrer mount is high so that the stuffing box is easily accessible. Samples can be removed through the cock seen at the upper right.

Automated data processing, data reduction, spectral interpretation, and reporting are also integral parts of open-access sample analysis. Mallis et al. [33] described the use of an open-access system with e-mail capabilities to distribute processed data reports to the chemist. Several methods have been developed, including structure elucidation with in-source collision-induced dissociation (CID). 

A schematic of the Thermo Scientific MALDI source [124] is shown in Figure 2.24b. The MALDI source region includes a movable sample plate ( 1) with a 1pm positioning accuracy and approximately 12 x 8cm free travel to access sample plate sizes of the standardized microtiter plate format, a RF-only quadrupole with auxiliary DC resistive rods (DC aux) mounted parallel to and in the gaps between the RF rods ( 3). The skimmer ( 4) separates the source region held at about 0.1 mbar from the next pressure region. On the front side, a 4 mm aperture ( 2) is placed equidistant from both the RF rods assembly and the sample plate. 

---