Reversed phase high performance liquid chromatographic determination of dissolved aluminium in open ocean seawater

Abstract

Popular shipboard techniques to determine dissolved aluminium in open ocean seawater have two major disadvantages: relative to HPLC techniques, they require large sample volumes; and, in practice they are are only semi-automated. To address these two issues, the application of a reversed-phase high performance liquid chromatographic (RP-HPLC) method for the determination of the aluminium in open ocean seawater was developed. With this method, dissolved aluminium in the sample was complexed with lumogallion at pH 5.5 by the addition of a reagent, producing the fluorescent aluminium-lumogallion complex. This complex was concentrated onto a Chromolith ® RP-18e Guard (10 × 4.6 mm) column and eluted with 95% methanol into a fluorescence detector (λ ex = 505 nm, λ em = 574 nm). Sample pre-treatment required 10 h (>100 samples can be prepared simultaneously) and sample analysis required 375 mL of sample per vial analysed, with 10 mL and 2.7 min per injection. Total required sample volume (including rinses) was 1.5 mL. Limit of detection was 0.13±0.05 nM, with precision of 2.7% at 1 nM on SAFe reference samples. Agreement with SAFe reference samples was within 4.6±4.6% (n = 13). The technique is robust, inherently automated and could easily be applied shipboard for open ocean analyses. It provides improvements in sample efficiency, operational robustness and automation relative to popular shipboard techniques, especially when applied to samples with dissolved aluminium concentrations that approach the limit of detection. This project was a contribution to the GEOTRACES program.

Advances in the offline trace metal extraction of Mn, Co, Ni, Cu, Cd, and Pb from open ocean seawater samples with determination by sector field ICP-MS analysis

“…In order to help determine the distribution of trace elements as well as their sources and sinks in the ocean, many single element techniques such as ow injection analysis using chemiluminescence, [31][32][33][34] voltammetry, 35,36 high-pressure liquid chromatography extraction with uorescence detection, 37 graphite furnace atomic absorption spectrometry aer liquidliquid extraction 38 or ICP-MS 39 have been used with adequate detection limits and sensitivities. 40 Despite the importance of (co)-limiting metals in phytoplankton growth, simultaneous determination of multiple dissolved trace element concentrations has not been as common.…”

A sensitive flow-injection analysis method with iminodiacetate chelation and spectrophotometric detection for on board determination of trace dissolved aluminum in seawater

“…There are numerous methods for Al determination, including graphite furnace atomic absorption spectrometry (GF-AAS), 5,6 electrothermal atomic absorption spectrometry (ETAAS), 7 inductively coupled plasma optical emission spectrometry (ICP-OES), 8 inductively coupled plasma mass spectrometry (ICP-MS), 9-11 uorometry [12][13][14][15][16][17][18] and spectrophotometry. [19][20][21] However, there are limitations in these methods, such as the severe matrix effect, complicated procedures, and shipboard analysis.…”