Hazards in sampling

Apart from the toxic nature of many gases, the additional hazards are those of excessive release of gas due to pressure changes, spontaneous ignition of flammable gases and sudden vaporisation of liquefied gases. 

With liquids, dangers frequently arise from easily volatilised and readily flammable liquids. In all cases precautions should be greater than under normal circumstances due to the unpredictable nature and conditions of taking samples. The sampler must always be prepared for the unexpected, as can arise, for example, if a container has built up excess pressure, or if the wrong liquid has been packed. Toxic and unknown liquids should never be sucked along tubes or into pipettes by mouth. 

Even the sampling of solids must not be casually undertaken, and the operator should always use a face mask as a protection until it is established that the powdered material is not hazardous. 

It should be borne in mind that sampling of radioactive substances is a specialist operation at all times and should be carried out only under strictly controlled conditions within restricted areas. In almost all instances the operator must be protected against the radioactive emanations from the substance he is sampling. 

Correct sampling of materials is therefore of importance in two main respects firstly to obtain a representative portion of the material for analysis, and secondly to prevent the occurrence of accidents when sampling hazardous materials. 

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