After sampling, water samples should be analyzed immediately. If forced to be stored, any water quality parameters require specific treatment to the sample. In addition to treatment with chemicals, preservation of the most common is the cooling at a temperature of 4 ° C during transportation and storage. At this temperature, bekteri activity is inhibited. Samples were delayed measurement and storage must be carried out should be labeling on the bottles of the samples used. Labeling sample vials is very important to avoid mistakes when analyzing the sample. Labeling a minimum, include the recording of data on:
1) Type of water, eg ground water, waste water, river water, sea water
2) The location or sample points, mentioned the exact location / clear where samples were taken
3) The parameters to be checked
4) Current weather sampling
5) Date and time (hours) sampling
6) Name the taking of samples
Water sampling frequency depends on several factors, including changes in pollution load and discharge water, water quality monitoring purposes, and analysis capabilities. In principle, almost all parameters of water chemistry can be accurately analyzed in the laboratory. But the results of this analysis will be to no avail if the method of taking sampelair in lapangantidak according to the nature of some of the parameters of water chemistry is very sensitive to direct contact with air, then the sampling must be such that the contact of water with air can be avoided and the water can be brought to the surface and when it reached the laboratory, it will not change the nature (Anonymous, 1992).
Sample preservation techniques
Preserving a perfect example to sample the water is unlikely, given the stability of the properties of each of the elements contained in the sample can not be achieved perfectly. The function of preservation is to slow down the process of chemical and biological changes are not inevitable. Pickling is very difficult because almost all the preservatives disturbing for some testing.
Storing the samples at low temperature (4 ° C) may be the best way. To preserve the sample until the next day reagent use preservatives do not interfere during the analysis process and additions into the bottle to do before filling an example so that samples may be preserved as soon as possible. No single method of preservation is satisfactory because it’s been preservation in accordance with the objectives of the investigation.
All preservation methods are inadequate possibilities for materials suspended. The use of formaldehyde is not recommended because it affects so many checks. Monitoring methods are generally limited to control pH, addition of chemicals, refrigeration and freezing. Certain parameters is more influenced by sample storage prior to analysis than others.
Some types of cations can be lost because it is absorbed by the walls of a glass container such as aluminum (Al), Cadmium (Kd), chromium (Cr), Copper (Cu), iron (Fe), lead (Pb), manganese (Mn), Silver (Ag ) and Zinc (Zn). We recommend to the parameters above, a sample was taken separately and accommodated in a clean bottle and acidified with concentrated HCl or concentrated H2SO4 to pH 2.0 to reduce the absorption of the walls of the container. The parameters of pH, temperature and dissolved gases should be immediately checked in the field because those parameters easily changed in a short time.
Figure 25. Doing preservation of water samples
Water samples obtained from sampling sites before measurements were taken during storage or handling needs as presented in Table 15. Here is presented on the example of water management (water sample) mainly concerns the preservation or preservation, container type and duration of storage.