Forensic Chemistry > 1. The job of the forensic chemist is to identify materials and trace their origins > Ensuring Accuracy And Preventing Contamination of Samples >
Outline precautions that may be necessary to ensure accuracy and prevent contamination of samples for analysis
- Three major sources of contamination:
- Unnecessary materials are introduced during collection, handling and transporting.
- The laboratory set up is inappropriate for work (e.g. flaking and corroding paint, lack of ventilation, dirty laboratory).
- The analyst is careless and does not follow laboratory rules (e.g. not wearing of suitable clothing such as gloves, mask, and safety glasses).
- Precautions that may ensure accuracy and prevent contamination of samples for analysis:
- careful collection and handling of the samples by having separate witnesses during sample collection, documentation and analysis
- bagging, sealing and labelling the sample immediately
- storing the sample in conditions that may prevent deterioration or contamination
- sterilizing the apparatus and equipment
- using suitable clothing such as gloves, mask, and safety glasses
- using controls in testing (error margins must be stated)