The Evidence Guide describes the underpinning knowledge and skills that must be demonstrated to prove competence.

Critical aspects of competency

Competency must be demonstrated in the ability to perform consistently at the required standard. In particular, the assessor should look to see that the candidate:

uses appropriate materials, equipment and procedures to prepare solutions

follows appropriate OHS (and hygiene, if appropriate) procedures

uses all equipment safely, efficiently and in accordance with enterprise procedures

uses enterprise procedures to calculate concentrations

identifies solutions not fit for use

uses titrations to determine the concentration of solutions

labels, stores and disposes of solutions appropriately

records and present data appropriately.

Underpinning knowledge

Competency includes the ability to apply and explain:

relevant biological, chemical, food and laboratory terminology

basic theory of acids, bases, salts, buffers and neutralisation

enterprise procedures for preparing solutions

calculations required to prepare specified amounts of solutions of specified concentration

appropriate OHS procedure for preparing, handling and disposal of solutions

use of MSDSs

relevant health, safety and environment requirements.

Assessment context and methods

This unit of competency is to be assessed in the workplace or simulated workplace environment.

The following assessment methods are suggested:

inspection of solutions prepared, labelled and stored by the candidate

review of solution records and workplace documentation completed by the candidate

feedback from peers, and supervisors

observation of the candidate preparing working solutions

oral or written questioning.

In all cases, practical assessment should be supported by questions to assess underpinning knowledge and those aspects of competency which are difficult to assess directly. Questioning techniques should suit the language and literacy levels of the candidate.

Interdependent assessment of unit

This unit of competency may be assessed with:

PMLDATA200A Record and present data

PMLOHS302A Participate in laboratory/field workplace safety.

Resource implications

Resources may include:

standard laboratory equipped with appropriate equipment and reagents

standard operating procedures and testing methods

access to appropriate containers and storage facilities.

This competency in practice

Manufacturing

When starting materials used for the manufacture of common household materials are in transit from the supplier to the manufacturer, they may degrade if subjected to conditions, such as heat, moisture, light and oxygen. Even when the supplier ships quality materials to the manufacturing plant, the materials may be substandard when they arrive. Quality control tests are designed to test starting materials to ensure they are within specification. For example, aspirin forms salicylic acid when stored under adverse conditions. Laboratory assistants prepare and monitor the quality of solutions, such as ferric chloride solution, which gives an intense violet colour when added to salicylic acid but gives no colour with aspirin. Absence of the violet colouration indicates that breakdown of the aspirin hasn't occurred.

Biomedical

A laboratory assistant made up 1 litre of buffer solution using buffer tablets and a 1 litre volumetric flask as specified in the method. To ensure the solution was suitable for use, the assistant measured the pH and found it was within acceptable range. The assistant then appropriately labelled a storage vessel and stored the buffer according to requirements. By following enterprise procedures the shelf life of the buffer was maximised.

Environmental

An environmental laboratory is contracted to determine the acidity of water samples taken from local lakes and streams. A laboratory assistant is required to make up small batches of 0.01M sodium hydroxide and to determine its concentration by titrating it against a standard solution of potassium acid phthalate using phenolphthalein indicator. This procedure is carried out monthly to ensure that the concentration of the sodium hydroxide solution is accurately known. Alternatively, the laboratory assistant may be required to prepare and standardise a fresh batch of sodium hydroxide on a monthly basis. In this case, he/she must understand the underpinning knowledge of basic acid/base theory, potential problems of interferences (such as slow absorption of carbon dioxide by sodium hydroxide solution) so as to ensure that the concentrations of workup solutions are accurately known. He/she must also be skilled in calculating and performing dilution when required to prepare such low concentrations (0.01M) of working solutions.

Key Competencies

The seven key competencies represent generic skills considered for effective work participation. The bracketed numbering against each of the key competencies indicates the performance level required in this unit. These are stand-alone levels and do not correspond to the Australian Qualifications Framework (AQF).

Level (1) represents the competence to undertake tasks effectively

Level (2) represents the competence to manage tasks

Level (3) represents the competence to use concepts for evaluating and reshaping tasks.

The range of variables relates to the unit of competency as a whole. It allows for different work environments and situations that will affect performance.

Where reference is made to industry Codes of Practice, and/or Australian/international standards, it is expected the latest version will be used.

This unit of competency describes the work conducted by supervised laboratory assistants who prepare a range of working solutions for laboratory use. Test solutions include those required to perform laboratory tests. All operations must comply with relevant standards, appropriate procedures and/or enterprise requirements. These procedures include or have been prepared from:

Australian and international standards, such as:

AS 2162.1 General - volumetric glassware

AS 2163 Laboratory glassware - measuring cylinders

AS 2165 Laboratory glassware - burettes

industry methods, such as American Association of Cereal Chemists (AACC) Solution methods

Codes of Practice, such as GLP and GMP

material safety data sheets (MSDSs)

National Measurement Act

standard operating procedures (SOPs)

equipment manuals

equipment startup, operation and shutdown procedures

calibration and maintenance schedules

quality manuals

enterprise recording and reporting procedures

production and laboratory schedules

material, production and product specifications.

The nature of test solutions will depend on the enterprise and the range of testing carried out. Typical test solutions may include:

solutions required for diagnostic/analytical and limit tests in food and chemical laboratories, such as sulphates, chlorides, heavy metals

solutions, such as stains for standard diagnostic/analytical procedures in biomedical/environmental laboratories, such as cell staining, fixation of cells and tissues, suspension of cells, titrimetric indicators

solutions required for laboratory maintenance and disinfection, such as 70% ethanol, hypochlorite.

Laboratory equipment may include:

pH meters

balances

magnetic stirrers, waterbaths and hot plates

measuring cylinders, beakers, conical flasks, volumetric flasks, pipettes, burettes

filter papers and funnels

fume cupboards.

Hazards may include:

corrosive chemicals, such as acids and alkalis

sources of heat, such as burners

sharps, broken glassware

spillages.

Safety precautions may include:

use of material safety data sheets (MSDSs)

use of personal protective equipment, such as safety glasses, gloves and coveralls

correct labelling of reagents and hazardous materials

handling and storing hazardous materials and equipment in accordance with labels, MSDS, manufacturer's instructions, enterprise procedures and regulations

regular cleaning and/or decontamination of equipment and work areas.

Monitoring quality of solutions can include:

noting turbidity to exclude absorption of moisture

noting deposits to exclude microbial contamination or chemical degradation

noting crystals to exclude evaporation

conducting titrations to check concentration

noting colour changes indicating a pH shift with solutions containing indicators

checking expiry dates on solution containers.

Concentration terms may include: % w/w, % w/v, % v/v, ppm (mg/L), molarity.

Health, safety and environment

All operations to which this unit applies are subject to stringent health, safety and environmental (HSE) requirements, which may be imposed through State or Federal legislation, and these must not be compromised at any time. Where there is an apparent conflict between performance criteria and HSE requirements, the HSE requirements take precedence.

All operations assume the potentially hazardous nature of samples and require standard precautions to be applied. Users should access and apply current industry understanding of infection control issued by the National Health and Medical Research Council and State and Territory Departments of Health. All operations are performed in accordance with standard operating procedures.