Marine samples

Figure 5. Concordia diagram similar to Figure 4 illustrating the concordia curve for initial = 150 (appropriate for marine samples), with age in ka depicted parametrically along concordia. Also illustrated are continuous uranium gain/loss model curves for samples with primary ages of 80 ka (dashed) and 150 ka (thin solid curve). See text for discussion of this model and related models (after Cheng etal. 1998).

Nozaki Y, Zhang J, Takeda A (1997) °Pb and °Po in the equatorial Pacific and Bering Sea the effects of biological productivity and boundary scavenging. Deep-Sea Res II 44 2203-2220 Nozaki Y, Dobashi F, Kato Y, Yamamoto Y (1998) Distribution of Ra isotopes and the °Pb and °Po balance in surface waters of the mid Northern Hemisphere. Deep-Sea Res. 145 1263-1284 Pates JM, Cook GT, MacKenzie AB, Anderson R, Bury SJ (1996) Determination of Th-234 in marine samples by liquid scintillation spectrometry. Anal Chem 68 3783-3788... 

Hodge et al. [689] have described a method for the determination of platinum and iridium at picogram levels in marine samples, based upon an isolation of anionic forms of these elements using appropriate resins, with subsequent purification by uptake on a single ion-exchange bead. All steps are followed by radiotracers, and yields vary between 35 and 90%. Graphite furnace AAS was employed as the determinative step. 

The plutonium concentration in marine samples is principally due to environmental pollution caused by fallout from nuclear explosions and is generally at very low levels [75]. Environmental samples also contain microtraces of natural a emitters (uranium, thorium, and their decay products) which complicate the plutonium determinations [76]. Methods for the determination of plutonium in marine samples must therefore be very sensitive and selective. The methods reported for the chemical separation of plutonium are based on ion exchange resins [76-80] or liquid-liquid extraction with tertiary amines [81], organophosphorus compounds [82,83], and ketones [84,85]. 

Ray, L.E., H.E. Murray, and C.S. Giam. 1983. Organic pollutants in marine samples from Portland, Maine. Chemosphere 12 1031-1038. 

Gron [23] has reviewed methods for the determination of halogenated organic compounds (adsorbable, volatile and extractable), with particular reference to their applicability to wastewaters and marine samples (marine sediments and marine organisms). Typical analytical results for marine... 

All four dissolution procedures studied were found to be suitable for arsenic determinations in biological marine samples, but only one (potassium hydroxide fusion) yielded accurate results for antimony in marine sediments and only two (sodium hydroxide fusion or a nitricperchloric-hydrofluoric acid digestion in sealed Teflon vessels) were appropriate for determination of selenium in marine sediments. Thus, the development of a single procedure for the simultaneous determination of arsenic, antimony and selenium (and perhaps other hydride-forming elements) in marine materials by hydride generation inductively coupled plasma atomic emission spectrometry requires careful consideration not only of the oxidation-reduction chemistry of these elements and its influence on the hydride generation process but also of the chemistry of dissolution of these elements. 

Chlorophylls and other pigments have been frequently investigated in marine samples. As the amount of chlorophyll may be used as a marker for phytoplankton production its determination is of paramount importance in sea research [274], HPLC data have been used for the study of phytoplankton community structure [275] and for the indentification of phytoplankton groups [276], Earlier advances in HPLC pigment analysis have been reviewed [277],... 

Dimethylarsinodimethyldithioarsinate, secondary bonding by, 15 29-30 Dimethylarsinothioylethanol, in marine samples, 44 161... 

Dimethylarsinoylribosides, in marine samples, 44 155-158, 161, 173, 174, 177 2,3-Dimethylbutadiene, vanadium complex with, 4 82... 

Marine biological material, radioactivity of, 3 315-316 Marine samples arsenic in, 44 148-151 compounds found, 44 151-162 occurrence and distribution, 44 149-151, 162-169... 

Sedimentation equilibrium technique, 19 256 Sedimentation velocity technique, 19 256 Sediments, arsenic in marine samples, 44 149, 162-164, 169, 181 [Se U ] cations, 35 297-298 Selective vaporization, for preparation of actinide metals, 31 12-13, 26 Selenide, production, 38 82 Selenium... 

Within the operationally defined marine bacteria , i.e., bacteria isolated from marine samples on marine media, bioactive compounds have been reported from Pseudoalteromonas, Cytophaga, Alteromonas, Micrococcus, Bacillus, Acinetobacter, Agrobacterium and Pseudomonas or from unidentified bacteria (Fig. 2). 

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