Plastic samplers

The limitations of glass and stainless steel samplers have led many workers to use the more readily available plastic samplers, sometimes with the full knowledge of the risks and sometimes with the hope that the effects resulting from the choice of sampler will be small compared with the amounts of organic matter present. The effects of the containers can be of three classes ... 

The first case is the most likely to be a problem with new plastic samplers. Although there is little in the literature to substantiate the belief, folklore has it that aging most plastic samplers in seawater markedly reduces the subsequent leaching of plasticisers. The second case is known to be a problem in fact, the effect is used in the various Teflon surface film samplers already mentioned. This problem alone would seem to militate against the use of Teflon for any sampling of organic materials, unless a solvent wash of the sampler in included routinely. With such a solvent wash, we introduce all of the problems of impurities in the reagents. 

The third, and largely unexpected, case appeared as a problem in the analysis of petroleum hydrocarbons in seawater [24]. In this case, petroleum hydrocarbons, picked up presumably in the surface layers or surface film, were carried down by the sampling bottles and were measured as par t of the pollutant load of the deeper waters. While the possibility of absorption and subsequent release is obviously most acute with hydrophobic compounds and plastic samplers, it does raise a question as to whether any form of sampler which is open on its passage through the water column can be used for the collection of surface-active materials. The effects of such transfer of material maybe unimportant in the analysis of total organic carbon, but could be a major factor in the analysis of single compounds or classes of compounds. 

Because soil is abrasive, it can be expected that small amounts of the sampler itself may be transferred from the sampler to the sample during sampling. Many soil samplers are constructed of metal and pose no problems for most samples. Figure 7.3 shows two of many types of metal samplers available. Plastic samplers of similar design are also available. If low concentrations of metals are an important component of the analysis, then knowing the sampler composition may be important. 

A typical example of fluorlmetrlc determination on dry reagent films is that of serum Immunoglobulins reported by Wang et al. [48]. The method uses a stabilized solid-phase immunoadsorbent consisting of an antigen Immobilized on a cellulose nitrate-acetate disc stuck to a Stiq plastic sampler. The polymer disc acts both as a substrate for Immobilization and as an even surface on which highly precise fluorlmetric determinations can be conducted. The assay... 

Each kit contnins 12 disposable plastic sampler-detectors and M-8 paper. 

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. 

Numbers result from common computer analyses and not all such figures will be necessarily significant PCS = Plastic-coated steel hydrowire SS = Stainless steel (type 302 unlubricated) hydrowire KEV = Kevlar hydrowire HB = Hydro-bios sampler MGF = Modified GO-FLO sampler Mod GF = Unmodified GO-FLO sampler Exw GF = Unmodified GO-FLO sampler NIS = Modified Niskin sampler m = mean sd = standard deviation... 

Although SPMDs are simple in design, the mechanisms governing their performance as passive samplers of HOCs can be quite complex (see Chapter 3). The underlying principle of molecular-size discrimination in the uptake and loss of chemicals by SPMDs is shown in Eigure 2.1. The sizes of the molecules shown in the illustration are scaled to the postulated 10 A diameter of the transient pores in the membrane. Temperature and the presence of plasticizers/solvent will affect the effective pore sizes. 

The fine particle airstream from the cyclone was sampled by two total filters in parallel. A Millipore Fluoropore 47 mm diameter Teflon filter with a 1 pm pore size was used for the first seven samples. Subsequent samples were obtained with a 0.4 pm pore size 47 mm Nuclepore polycarbonate filter because particle absorption measurements and elemental analysis by particle induced X-ray emission (PIXE) were easier and more accurate using the Nuclepore filters. In parallel with the Nuclepore filter, a TWOMASS tape sampler collected aerosol using a Pallflex Tissuequartz tape. The aerosol deposit area was 9.62 cm on the Nuclepore and Millipore filters and 0.317 cm on the Tissuequartz tape. The flow rate was 16-20 1pm through the Nuclepore and Millipore filters and 10 1pm through the Tissuequartz tape. Each Millipore or Nuclepore filter was placed in a labeled plastic container immediately after collected, sealed with Parafilm, enclosed in a ziplock bag, and placed in a refrigerator in the trailer. The tape in the TWOMASS sampler was advanced between samples. The tape sample was removed about once every 8-10 weeks and stored similarly to the Nuclepore filters. The TWOMASS was cleaned at that time. All samples were stored in an ice chest during the return trip to Caltech. Field blanks were handled identically to the samples. Of approximately 100 filter samples collected in 1979, 61 were selected for analysis. The 61 were chosen to span the variation in bjp and to obtain representative seasonal and diurnal samples. Sample times varied from 6 to 72 hours, with an average of 20.1 hours. 

The evaluation of diffusion samplers reported in this paper was initiated as an internal project at Arthur D. Little, Inc., to develop for ourselves a base of data which would help us to judge the utility of diffusion samplers in our work. Diffusion samplers were purchased from the two firms active in the marketplace when the field study began (early 1979), Abcor and 3M. A program was devised wherein, during each of approximately 50 surveys being undertaken in plastic fabrication plants, four to six diffusion samplers would be exposed, each adjacent to a charcoal tube personal sample. At the conclusion of the field sampling, a data base of over 100 pairs of samples (each pair including a diffusion sample and a charcoal tube sample) had been compiled for each of the two diffusion samplers. 

Centrifugal sampler. The unit consists of a propeller or turbine that pulls a known volume of air into the unit and then propels the air outward to impact on a tangentially placed nutrient agar strip set on a flexible plastic base. 

Fujii, M., Shinohara, N., Lim, A., Otake, T., Kumagai, K. and Yanagisawa, Y. (2003) A study of the emission of phthalate esters from plastic materials using a passive flux sampler. Atmospheric Environment, 37, 5495-504. 

To meet the need to monitor levels of 222Rn in houses, passive samplers have been developed which measure average concentrations over long periods and do not need power suplies. In the Karlsruhe dosimeter (Urban Piesch, 1981), a polycarbonate nuclear track detector foil is mounted inside a plastic cup. The mouth of the cup is closed with a filter to allow radon to enter but to exclude decay products. After exposure, the detector foil is etched and the tracks counted optically. This is a... 

Sampler 1 downstream of the water sampling will wash the trenching tool (shovel), sieve nest, both pans, the plastic funnel and both sets of thick black protective rubber gloves with stream water. The sieve nest (Fig. 4.5) is assembled on the top of the glass-fibre pan, in a stable position, as close to the sediment collection point as possible. The collection pan and sieves must be clean and free from any particulate matter before the commencement of sampling. 

A comparison of stainless steel samplers and plastic samples was previously done in the observation field of Tsukuba for several weeks. No significant differences were seen for the components determined in this report. 

At the sampling step, contamination from sampling bottles and hydrowire should be minimized [10], Old types of sampling devices such as Nansen and Knudsen are constructed mostly from brass, which may cause contamination of Cu and Zn into seawater. The recently developed Niskin plastic sampling bottle provides less contamination from the sampler walls. However, the materials used for the end-caps or springs, rubber or Teflon-coated stainless steel, sometimes release significant amounts of Ba, Cu, Sb and Zn [14]. 

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