Sampling equipment, marine

Table 17.1 Sampling equipment commonly used in the marine environment...

Fig. 10.19. IDR-HSQC-TOCSY spectrum of the complex marine polyether toxin brevetoxin-2 (7). The data were recorded overnight using a 500 pg sample of the toxin (MW = 895) dissolved in 30 pi of d6-benzene. The data were recorded at 600 MHz using an instrument equipped with a Nalorac 1.7 mm SMIDG probe. Direct responses are inverted and identified by red contours relayed responses are plotted in black. The IDR-HSQC-TOCSY data shown allows large contiguous protonated segments of the brevetoxin-2 structure to be assembled, with ether linkages established from either long-range connectivities in the HMBC spectrum and/or a homonuclear ROESY spectrum.

WATOX-82, -83, and -84 sampled air in the marine boundary layer. These sea-level measurements gave no information about upper-air transport. To overcome this deficiency, the fourth through the seventh Intensives incorporated data collected onboard two NOAA research aircraft, the NOAA WP-3D and the NOAA KingAir. (See Table III for the specific species measured.) Both aircraft carried sampling and analytical equipment designed to determine the vertical and horizontal chemical structure of the atmosphere. 

Air Point source emission stack, vent (e.g., laboratory hood, distillation unit, reactor, storage tank vent), material loading/unloading operations (including rail cars, tank trucks, and marine vessels). Fugitive emissions pumps, valves, flanges, sample coUection, mechanical seals, relief devices, tanks. Secondary emissions waste and wastewater treatment units, cooling tower, process sewer, sump, spill or leak areas. Equipment wash solvent or water, lab samples. 

This method, developed at the end of the 19th century, is still the most widely used when organic compounds have to be extracted from solid materials, like dusts, sand, soil, and marine sediments. It is particularly suitable when the organic material is strongly adsorbed on a porous solid matrix. Such a simple method presents several advantages the sample is repeatedly brought into contact with fresh portions of the solvent and no filtration is required after the leaching step, simultaneous extraction in parallel can be performed since the basic equipment is inexpensive, and finally it has the possibility to extract more sample mass than most of the latest methods [microwave extraction,... 

Schematic diagram of a drill ship equipped with traveling block heave compensator. (After Richards, A.F., and Zuidberg, H.M., Sampling and in situ geotechnical investigations offshore. In Marine Geotechnology and Nearshore/ Offshore Structures, ASTM STP 923, Chaney, R.C., and Fang, H.Y., eds., American Society for Testing and Materials, Philadelphia, PA, 51-73,1986. Reprinted with permission. Copyright ASTM.)...

Arsenic has a relatively high concentration in seawater (when compared with many other trace elements see Table 12-1) and is not present at high levels in materials used in the construction of ships, marine equipment, and samplers. Therefore, the problem of sample contamination is much less severe for this element and its species than for many other trace elements. Clean room facilities are not required for arsenic species determination. Care should, however, be taken in the laboratory to avoid the possibility of contamination resulting from the preparation and handling of standards. 

The concentration and behaviour of iron in ocean waters have been briefly outlined in Section 12.1.1 and Table 12-1. (For overviews see also Marine Chemistry , Vol.50 (1995 Nos. 1-4) and Vol. 57 (1997 p. 137-186)). For the determination of open-ocean Fe concentrations (i.e., in the sub-nanomol range) sufficient care must be taken not to contaminate the samples. The methods, specialized procedures and equipment necessary to cope with these extremely low concentrations are described in detail in Section 12.1. and 12.2.1. Here, we outline a spectrophotometric procedure for dissolved Fe concentrations in the pmol/L range. Such amounts occur in the marine environment under anoxic conditions and pH values of around 7 (e.g., in the Baltic or Black Sea). It can be explained by a steady diffusion of Fe(/7) species from organic-rich sediments into stagnant bottom water resulting in the enrichment of rather soluble iron(/l)sulphide. 

The equipment for sampling marine particles is briefly described in Chapters 1 and 2. In this section we emphasize the specific requirements for sampling particulate trace elements. The major points are, first, to avoid contamination, and second, to collect enough material for the detection of as many TE as possible even at very low concentrations. 

A number of steps are involved in the method and hence it is relatively time-consuming. On the other hand, a large number of samples may be processed at once, as only 1 mL of seawater is required. The technique is almost free of interferences and appears to detect monosaccharides only (MCHO). After a simple hydrolysis procedure the method may be employed to estimate concentrations of polysaccharides in seawater or in marine particulates. Since (in addition to glassware and chemicals) a photometer is the only equipment required, few problems are encountered when using the method in the field. 

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