Go-Flo bottles

Replicate unfiltrated water samples were collected for each participant for the comparison of pairs of sampling bottles on different hydrowires [29]. Modified GO-FLO bottles were employed on each of the three hydrowires,... 

The samples of sea water were collected with a Teflon suction pump or Go-Flo bottles, depending on the sampling depth. Immediately after collection the samples were filtered under N2 pressure through 0.45 pm pore-size filters (Millipore). Filtration was effected under a laminar flow hood using a closed Teflon system. The... 

The sampler itself should be constructed from noncontaminating and, equally important, nonadsorptive material. The sampler should also be capable of being lowered through the sea surface closed so as to avoid contamination from the organic-rich sea surface microlayer. Unfortunately, there is no ideal sampler. The modified General Oceanics Go-Flo bottles widely used by workers in the field of oceanic trace inorganic analysis are often the most suitable systems that are commonly available. In some cases (e.g., for halocarbons), special devices have been constructed to allow uncontaminated withdrawal for the sample... 

Water for the analysis of suspended particles may be collected with any clean water sampler used for oceanographic work, e.g., Niskin bottles, Go-Flo bottles, Nansen bottles. Hydrobios water samplers (see also Chapter 1). The sample volume will depend on the expected concentration of POM. In nearshore and/or biologically productive water, 0.5-2 L usually is an adequate sample volume. Ten litres may be required in particle-poor open ocean waters such as the Sargasso Sea. For sampling large volumes of water, 30 L Niskin bottles are recommended. Even larger volumes may be sampled with in situ pumps. (See Chapters 1,2 and 13). 

Data analysis was reduced to a separate one-way analysis of variance on the data from individual laboratories in order to examine the difference between types of sampling bottle on a single (common) hydrowire, and to determine the influences of the three types of hydrowire using a single type of sampling bottle (modified GO-FLO). Samples were replicated so that there were, in all cases, two or more replicates to determine the lowest level and analytical error. 

In our study, contact of the anoxic samples with oxygen was avoided. The samples were transferred from the samplers (Go-Flo, General Oceanics, 5 L) into bottles equipped with three-way taps under N2 pressure. The bottles had previously been flushed with N2, and they were completely filled. Filtration in the laboratory with acid-cleaned 0.45- xm cellulose nitrate filters (Sartorius) and a polycarbonate filtration unit (Sartorius) was also carried out under nitrogen gas. Most analytical determinations were performed in the laboratory on the sampling day. 

Deep water samples were collected directly from the ship, using a 20-30 1 sampling bottle (Teflon -coated and with pressurization capability, Go-Flo, General Oceanics, USA) which was immersed by means of a non-metallic (Kevlar) hydrowire. To sink the bottle a plastic covered ballast was used, attached to the wire at least 20 m below the bottle. 

Figure 5.2. Cadmium (a) and Pb (b) concentrations in the ultrapure water used to condition Go-Flo samplers (different symbols refer to different bottles). Concentration was detected in aliquots of 50 ml of water where 300 pi of satured KCl were added(- - stands for the blank). Adapted from Capodaglio et al. (88).

A few liters of surface water can be sampled directly with cleaned glass bottles that can also be used for sample storage. For sampling at different depths, Go-flo or Niskin bottles are more suitable, and allow sampling volumes of up to 501. If it is not possible to extract the samples immediately after sampling, these are stored at temperatures below 0°C in stainless steel or glass containers, rinsed beforehand with pesticide grade acetone followed by n-hexane. 

Plastic samplers are cleaned internally in a manner similar to that described for plastic bottles. Go-Flo samplers (Niskin type see Qiapter 1) are first thoroughly cleaned with a detergent, then rinsed with tap water and, after soaking in about 1 mol/L HQ (a.g.) for several days, flushed with a final rinse of purest distilled water. Afterwards, the samplers are wrapped in clean plastic bags for storage. 

Bottle samplers (e.g., Niskin, Nansen, Go-Flo, etc.) allow the collection of discrete water samples (0.5-30 L), whereas the acquisition of large volumes (100-1000 L) or a continuous... 

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