Methods for Collection and Analysis of Water Samples

Environment can be classified into three basic source which are water, land and air. The water is actually take up to 71% surface of the earth. Thus, in this case we will focus on the water analysis. The definition of water analysis is different types of liquid streams is being continuous sampling and different types of water sample’s quality is being analysis. Different liquid streams comes from various places such as groundwater, lakes, rivers, ponds and even drinking water. Why is water analysis so important? Water analysis is very important due to the contaminants can be analyzed and water-borne diseases can be prevented.

Drinking water is our basic in our daily life and as we assume our drinking water is very clean and it is good for us to maintain our health. However, we will never expect there will be many harmful contaminants from our drinking water which will be consumed to our body which might be dangerous and affect our health. Dissolved minerals, organic compounds or living organisms might be in our drinking water which cannot be seen with our naked eyes.

Water analysis is not only for drinking safely purpose and environment with healthy lifestyle, water analysis can also let industrial process improved for better products. People as an industry must always stay alert for the latest trends, news and regulations about water sources effect and let the consumers know about properly analyzing water and treating their water sources. Analysis water regularly is to make sure that all the drinking water is safe which might affect our health, determine the effectiveness of water treatment system and specific water quality problems and which the water is suitable or not for intended agricultural use.

If the water is exposed to air for a period of time, the quality of water may change. The physical changes of the water might not that easy to be seen but the quality has already changed. To ensure water treatment system is working effectively, controlling the water quality is necessary to provide the best quality of water. There are many types of method for water analysis such as gas chromatography, ion chromatography, UV-Vis spectroscopy, bacteriological tests, halogen test and ozone treatment.

The water sampling is the preparation stage before instrumental analysis. Water is available in a variety in a different types or classification, including surface water, ground water and spring water, waste water, saline water, estuarine water and brines, and others. It may appear that water is homogenous, but in fact, in most cases, it is not.

Spatial and temporal variation in water makes it heterogeneous; making it often difficult to obtain a representative sample. For an example spatial variation can occur within a lake due to changes in flow, differences in chemical composition as well as temperature variation. In addition, temporal variation can occur due to heavy precipitation as well as seasonal changes resulting in low lake water level.

Water samples are collected using the spring loaded water sampling device. It is essentially an open tube with a closure mechanism at either end; the tube is made of either stainless steel or PVC. Between 1 and 30 L of sample can be collected. The sampling device is lowered in to water to desired depth using a distance calibrated line. Then, both ends of the device are mechanically, and remotely, opened for a short time. After closing both ends the sample is brought back to the surface and the sample transferred into a suitable container.

Other than that, there are also many sampling systems for examples like manual sampling system, system for sampling the benthic boundary layer at different depths and extraction techniques. The manual sampling system is including the simple sampler for swallow water, sampler for large quantities in shallow water, simple sampler for deep water, deep water sampler with no adding air to sample, deep water sampler for trace element with allowing air to mix with the sample; whereas for the benthic boundary layer sampling method consists of automatic sampling system, sampling average concentration, sampling average concentration, event-controlled sampling of industrial short-term contamination and rapid underway monitoring. For extraction techniques, the most common technique is liquid-liquid extraction.

Gas chromatography is widely used techniques whose first application date back more than 60 years. Since then, development has continued making the best use of the extreme sensitivity, versatility, the possibilities of automation and the ease with which new analyses can be developed. Because separation of compound mixtures on the column occurs while they are in the gaseous state, solid and liquid samples must first be vaporized.

This represent, without hesitation, the greatest constraint of the gas phase chromatography and weights against it, since its use is limited to the study of thermostable and sufficiently volatile compounds. However, the applications are numerous in all domains and the development of high speed or multidimensional gas chromatography make this technique even more attractive. It is very great sensitivity permits detection of quantities of the order of pictograms for certain compounds.