Comparison of Laser and Ion Microprobe Detection Sensitivity for Lead in Biological Microanalysis

Linton, Richard W.; Bryan, Scott R.; Schmidt, Péter; Griffis, D. P.

doi:10.1021/ac50001a027

Cited by 12 publications

(3 citation statements)

References 8 publications

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“…Assuming no spectral interferences, a detection limit for Al of c. 1 /ug g~^ (37 nmol g^^) or better can be achieved by SIMS (Linton et al, 1980;Lazof et al, 1994a), a figure which is at least an order of magnitude better than for EDXMA (Chandler, 1979;Linton et al, 1980; but see Marienfeld & Stelzer, 1993, who claimed a detection limit not better than 2-3 //,mol g"^), "Al NMR (Nagata et al, 1991) and LAMMA (Verbueken et al, 1984;Linton et al, 1985), and more than two orders of magnitude better than PIXE (Hult et al, 1992). The latter technique apparently lacks sufficient sensitivity to measure Al in various subcellular structures and is therefore only suitable for gross localization of Al accumulated in root tissues.…”

Section: In Situ Techniques For Measurement Of Aluminiummentioning

confidence: 99%

Uptake of aluminium by plant cells

1996

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SUMMARY The question of intracellular or extracellular primary lesion in the Al toxicity syndrome is unresolved. One of the crucial points for answering that question is quantification of Al fluxes across the plasma membrane within seconds or minutes of exposure of roots to Al, i.e. concurrent with or preceding the first symptoms of Al toxicity. A review of the available literature on Al uptake shows that there is abundant information on Al accumulation in root tissues only after the relatively prolonged uptake period, ranging from 30 min to over 24 h. Most of these reports either assume or claim explicitly that intracellular Al was measured, even though Al ions are bound strongly to negative charges in the apoplasm. Therefore, an effective and complete desorption of apoplasmic Al after the uptake period is crucial for measurements of intracellular Al. However, published studies do not seem to have desorbed cell‐wall‐bound Al appropriately. Recent studies with giant algal cells of Chara corallina, where physical separation of cell wall and cytoplasm after the uptake period can be achieved surgically, showed that desorption of Al from the apoplasm, even employing a wider variety of desorbents and more stringent conditions than in any of the previously published reports, cannot be achieved completely within 5 h. Consequently, measured rates of uptake of Al across the plasma membrane of intact Chara cells employing the cell wall/cytoplasm separation technique are up to several orders of magnitude lower than previously published values in which cell‐wall Al was attributed to the transmembrane uptake component. Although there is no doubt that Al does cross the plasma membrane, no information exists about which Al species or complexes take part in the transmembrane flux, mainly because of complexities inherent in Al speciation at the solution/ion exchanger (i.e. the cell wall and the membrane) interface. Similarly, it is not known which membrane transporters are involved in transport of Al across the plasma membrane. The Al‐resistant plant genotypes generally accumulate less Al in the root tips than do the Al‐sensitive genotypes. No direct relationship, however, appears to exist between increased organic acid extrusion as a mechanism of resistance to Al and decreased transmembrane flux of Al. Al‐accumulator plant species accumulate relatively large amounts of Al in their tissues without having a greater Al uptake rate than non‐accumulator genotypes. Progress in deciphering structural and functional aspects of transport of Al across the plasma membrane of intact plant cells will rely on using giant algal cells in which physical separation of the cell wall and the cytoplasm can be achieved, because, at present, there is no reliable quantitative method which can overcome problems presented by a relatively large apoplasmic Al pool remaining after desorption of intact root cells of higher plants.

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Section: In Situ Techniques For Measurement Of Aluminiummentioning

confidence: 99%

Uptake of aluminium by plant cells

1996

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“…In some reports, an acceptable agreement with the model's predictions is shown, whereas in others the inapplicability of the approach is stressed and the use of calibration curves is proposed as an alternative (134)(135)(136)(137)(138)(139)(140)(141)(142)(143)(144). A variety of instrumental factors require attention when quantitation is attempted (145).…”

Section: Signal Registrationmentioning

confidence: 99%

“…The comparative use of TOF LMMS and micro-ESCA and AES for the study of oxide layers on stainless steel revealed that LMMS was especially useful because of its higher sensitivity and its capability to detect light elements (162). TOF LMMS was shown to exhibit better detection limits than dynamic SIMS for the analysis of elements in biological materials (47,141).…”

Section: Techniquesmentioning

confidence: 99%