Maleic acid/ammonium hydroxide buffer system for preconcentration of trace metals from seawater

Pai, Su Cheng.; Chen, Tsai Chu.; Wong, George T.F.; Hung, Chin Chang

doi:10.1021/ac00206a026

Cited by 22 publications

(8 citation statements)

References 19 publications

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“…The pH of the acidified seawater samples was raised to ~5.5 by adding concentrated NH 4 OH and buffering with Maleic Acid/Ammonium Hydroxide (pH=5.8. Pai et al, 1990). Two mL of Biorad ® Chelex 100 resin (in 2N HNO 3 ), 100-200 mesh, were packed in a Biorad ® polyprep column (bed volume: 2 mL, conical, 0.8 cm mean internal diameter, 4 cm height; 10 mL reservoir).…”

Section: Transition Metals Separation From Seawater Matrixmentioning

confidence: 99%

Cadmium isotopic composition in the ocean

Lacan

François

et al. 2006

Geochimica et Cosmochimica Acta

154

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The oceanic cycle of cadmium is still poorly understood, despite its importance for phytoplankton growth and paleoceanographic applications. As for other elements that are biologically recycled, variations in isotopic composition may bring unique insights. This article presents i) a protocol for the measurement of cadmium isotopic composition (Cd IC) in seawater and in phytoplankton cells; ii) the first Cd IC data in seawater, from two full depth stations, in the northwest Pacific and the northwest Mediterranean Sea; iii) the first Cd IC data in phytoplankton cells, cultured in vitro. The Cd IC variation range in seawater found at these stations is not greater than 1.5 ε Cd/amu units, only slightly larger than the mean uncertainty of measurement (0.8 ε Cd/amu ). Nevertheless, systematic variations of the Cd IC and concentration in the upper 300m of the northwest Pacific suggest the occurrence of Cd isotopic fractionation by phytoplankton uptake, with a fractionation factor of 1.6±1.4 ε Cd/amu units. This result is supported by the culture experiment data suggesting that freshwater phytoplankton (Chlamydomonas reinhardtii and Chlorella sp.) preferentially take up light Cd isotopes, with a fractionation factor of 3.4±1.4 ε Cd/amu units. Systematic variations of the Cd IC and hydrographic data between 300 and 700m in the northwest Pacific have been tentatively attributed to the mixing of the mesothermal (temperature maximum) water (ε Cd/amu =-0.9±0.8) with the North Pacific Intermediate Water (ε Cd/amu =0.5±0.8). In contrast, no significant Cd IC variation is found in the northwest Mediterranean Sea. This observation was attributed to the small surface Cd depletion by phytoplankton uptake and the similar Cd IC of the different water masses found at this site.Overall, these data suggest that i) phytoplankton uptake fractionates Cd isotopic composition to a measurable degree (fractionation factors of 1.6 and 3.4 ε Cd/amu units, for the in situ and culture experiment data, respectively), ii) an open ocean profile of Cd IC shows upper water column variations consistent with preferential uptake and regeneration of light Cd isotopes, and iii) different water masses may have different Cd IC. This isotopic system could therefore provide information on phytoplankton Cd uptake and on water mass trajectories and mixing in some areas of the ocean. However, the very small Cd IC variations found in this study indicate that applications of Cd isotopic composition to reveal aspects of the present or past Cd oceanic cycle will be very challenging and may require further analytical 3 improvements. Better precision could possibly be obtained with larger seawater samples, a better chemical separation of tin and a more accurate mass bias correction through the use of the double spiking technique.4

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Section: Transition Metals Separation From Seawater Matrixmentioning

confidence: 99%

Cadmium isotopic composition in the ocean

Lacan

François

et al. 2006

Geochimica et Cosmochimica Acta

154

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“…Several investigators have reported (Figura P. and McDuffie B., 1980,) that the effect of pH is an important factor for the binding of polyvalent metal ions into the amino-diacetate groups which act as chelating groups in the chelex-100 resin. However, the efficiency of the process depends on each possible combination of the loaded volume of sample, eluent amount, analyte (Pai et al, 1990) species, resin type and effect of pH adjusted by ammonium hydroxide/ maleic acid, as explained by Pai et al (1990). Maleic/ammonia buffer system is suitable for pH adjustment in the range of 2.0 -9.0.…”

Section: Recovery (%) When Eluted Bymentioning

confidence: 99%

“…The use of ion exchange resin is another option in order to overcome the problem of interference due to the salt matrix. It is well known that Chelex-100 cation-exchange resin has been employed in extracting cations from salt media in environmental samples such as sea water (Pai et al, 1990. ) and biological samples such as human fluid (Sun and Huang, 2003).…”

Section: Introductionmentioning

confidence: 99%

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Extraction of trace elements in human fluids using cation exchange resin (chelex-100) columns for ICP-MS analysis

Maithreepala

Doong

2014

J. Univ. Ruhuna

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A successful metal ion extraction method was developed using cation exchange resin packed disposable micropipette tip columns for the extraction of trace metal ions in human fluids. Using this method, concentrations of Mn, Ni, Cu, Zn, Cd and Pb ions in human urine were determined by inductively coupled plasma mass spectroscopy (ICP-MS). The main objective of this study was to develop a technique to overcome spectral interferences in ICP analysis of trace elements in biological fluids mainly due to salts present in the samples. The amount of resins packed to the column, amount of eluent needed to extract trace elements, and particle size of the resin were examined to determine conditions for metal extraction. The validity of this technique was evaluated by calculating recoveries of trace element concentrations of above elements in certified standard urine samples and by using the technique for trace metal spiked urine samples. The results revealed that Pb, Cd, Zn, Cu and Mn had good recoveries (about 95%) while Ni & Co had about 80% recovery. It was also found that the recoveries of trace elements depended on the concentrations of relevant elements in the samples.

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“…This paper describes a routine procedure for on-board operation of the Chelex-100 pre-concentration, with minimal maneuver. The principle is based generally on the method reported previously (Pai, 1988;Pai et al, 1988) but uses ammonium maleate as a buffer (Pai et al, 1990) instead of conventional ammonium acetate, and uses a more practical hanging bottle technique to avoid operational contamination. To demonstrate the applicability and precision of the method, a spiking experiment was carried out on board the R/V "Ocean Researcher I" at a station in the northern South China Sea, 100 km from Kaoshuing Harbour, Taiwan.…”

Section: Introductionmentioning

confidence: 99%