Iron(II) measurements on water column samples collected on the SIPEX II voyage of the Aurora Australis, 2012

Water samples for dissolved trace metal measurements were collected from the surface (15m) down to the 1000m using an autonomous intelligent rosette system (General Ocanics, USA) specially adapted for trace metal work and deployed on a Dyneema rope. The rosette was equipped with 12x10-L Niskin-1010X bottles specially modified for trace metal water sampling. This system has been successfully deployed on the RSV Aurora Australis during voyages au0703 and au0806. Care was taken to avoid any contamination from the ship and the operating personnel. Water samplers were processed aboard under an ISO class 5 trace-metal-clean laminar flow bench in to a trace-metal-clean laboratory container on the ship's trawl deck. All transfer tubes, filtering devices and sample containers were rinsed liberally with sample before final collection. Samples were then drawn through C-Flex tubing (Cole Parmer) and filtered in-line through 0.2 micron pore-size acid-washed capsules (Pall Supor membrane, Acropak 200). Regular sampling depths were as follows: 1000m, 750m, 500m, 300m, 200m, 150m, 125m, 100m, 75m, 50m, 30m, 15m. Samples were analysed within a minute of filtration. Iron(II) was detected with the luminol method combining the experimental set-up of Hansard et al. (2009) with the chemistry as described by Croot and Laan (2002). Samples were not acidified prior to analysis and were pumped directly into the flow cell without an injection valve. Care was taken to maintain a stable light field during measurements as the luminol reagent was found to be extremely sensitive to changes in light intensity.Photons from the reaction of luminol with iron(II) were counted with a Hamamatsu photomultiplier tube housed in a light-tight box. The signal was recorded using FloZ software (GlobalFIA) and the data for each run is stored in a separate file. There is a folder for each profile that contains all the files (automatically generated by the software), which are numbered. The file numbers (e.g. sample1, sample2,...) correspond to the runs as noted in the lab book (see scans). P.L. Croot, P. Laan (2002). Analytica Chimica Acta 466: 261-273. S.P. Hansard et al. (2009). Deep-Sea Res. I 56: 1117-1129.

用于溶解态痕量金属（dissolved trace metal）检测的水样采集工作，通过适配痕量金属采样需求的自主智能采水罗塞塔系统（General Ocanics，美国）完成，该系统搭载于迪尼玛（Dyneema）绳索之上，采样深度覆盖表层（15米）至1000米水深。该罗塞塔系统配备12个经特殊改造的10升Niskin-1010X型采水瓶，专供痕量金属水样采集使用。本系统已成功在RSV Aurora Australis科考船的au0703与au0806航次中完成部署。

采样全程严格规避船体与操作人员带来的污染风险。采集后的水样在科考船拖网甲板上的痕量金属洁净实验室容器内，于ISO 5级洁净层流工作台中完成预处理。所有传输管路、过滤装置及样品容器均在最终装样前用待测水样充分润洗。随后水样通过C-Flex管路（Cole Parmer）抽取，并经在线式0.2微米孔径酸洗过滤胶囊（Pall Supor膜，Acropak 200型）完成过滤。

标准采样水深依次为：1000米、750米、500米、300米、200米、150米、125米、100米、75米、50米、30米、15米。水样在过滤完成后1分钟内即开展分析检测。二价铁（iron(II), Fe²+）采用鲁米诺法（luminol method）检测，该方法整合了Hansard等人（2009）的实验装置方案与Croot及Laan（2002）所描述的化学检测体系。分析前无需对水样进行酸化处理，且未使用进样阀，直接将水样泵入流动池。由于鲁米诺试剂对光强变化具有极高敏感性，检测过程中需维持稳定的光照环境。鲁米诺与二价铁反应产生的光子，由置于暗箱中的滨松（Hamamatsu）光电倍增管进行计数。检测信号通过FloZ软件（GlobalFIA）记录，单次检测的所有数据均存储于独立文件中。每个检测剖面对应一个文件夹，内含软件自动生成的编号文件；文件编号（如"sample1"、"sample2"等）与实验日志（详见扫描件）中记录的检测批次一一对应。

参考文献：
1. P.L. Croot, P. Laan (2002). Analytica Chimica Acta, 466: 261-273.
2. S.P. Hansard et al. (2009). Deep-Sea Research Part I, 56: 1117-1129.