The same aluminium dish is used and the heating and evaporation is repeated as for the 1st fat extraction. These may have been operational or personal errors or contamination may have occurred. Two blanks were also created using 90ul of distilled water. The crucibles were then removed using forceps and weighed once they had cooled down. This indicates that although the outlier exhibited the most variation, it is not the only sample which exhibited experimental errors and therefore all three triplicates should be repeated with a higher level of accuracy and precision.
The carbohydrate was detected using the sum of percentages of moisture, crude protein, crude fat and ash and subtracting it from a hundred. The total moisture content was 2. This is continued until the sample is clear or reaches 420°C. The sample can be further used in calcium determination so should be saved. Following this, the dishes were removed, cooled using a desiccator and weighed. The method determines the total amount of reduced nitrogen present in an organic nitrogen- containing sample.
To determine the amount of moisture the air-oven method was used. These may have contributed to the results and caused the low level of accuracy. Carbohydrate content was exposed by means of subtracting the sum of all of the other components percentages from a hundred. There were both low levels of accuracy and precision in regards to total solids and total moisture. Proximate Analysis Laboratory Manual can be very useful guide, and proximate analysis laboratory manual play an important role in your products. This represents that it is likely that some experimental errors occurred.
This method is subject to numerous errors which could have occurred during the experiments to discover the components which are subtracted from a hundred per cent. Cautiously decant as much organic solvent as possible into the pre-weighed aluminium fat dish, use a fume hood during this part of the procedure. This result was precise but inaccurate. Therefore the level of accuracy was reasonably high. This was a reasonably high level of accuracy and precision for nitrogen and a satisfactory level of accuracy and low level of precision for crude protein. Using a conversion factor of 6.
This is an example of an operational and personal error. Set the distilling unit on automatic and connect a tube to the unit, there should be a plastic hose inside the tube. The standard error can provide an additional examination of the precision of the results. Contamination is likely to occur at this stage so the glass outlet tube should not be handles, but rather hold it via the plastic tubing. The most accurate method for determination of total moisture and total solid is the use of a vacuum desiccator, however this is a lengthy process which utilises materials not available in the laboratory and therefore the air oven method was utilised.
The sample was tested by this method and the results showed a high level of accuracy and precision. The standard error value of 5. Kjeldahl Method for Total Nitrogen. It is also the first step for specific elemental analysis. Combustion causes an expulsion of all water, the loss of carbon dioxide from carbonates, the conversion of iron pyrite into iron oxides and sulfur oxides, and other chemical reactions.
The ammonia reduces the viscosity of the product by dissolving the casein and neutralising its acidity. The problem with this method is that clear time is not an accurate measure of if digestion has occurred and this is an issue because clear time may occur a long time before decomposition has occurred. This method has not been accredited as being the most precise measurement but was used due to constraints used to determine the method. Resources include the equipment, analytical skills and available chemicals. Cool until the highest point of the tubes is touchable. The weights were taken with and without the lids. The temperature must not exceed 400°C otherwise volatile compounds may be lost.
The relative error nevertheless is higher which indicates that this still not an accurate sample regardless of the exemption of the outlier. The aluminium fat dish should then be placed on the hot plate at a temperature below 40°C and the solvents will evaporate from the dish. This method was performed in triplicate. The solid component showed both high accuracy and precision. The ash is representative of all the minerals contained within the powder sample, which is why it is important for analysing food.
Precision is related to the amount of statistical variation and accuracy is related to how near the measurement is to the accepted true value. The total solids are the matter which is left after moisture removal. This particular experiment used 2. Determination of Total Moisture and Total Solids The total moisture was determined using the total amount of moisture measured from the volatile matter that was lost when the sample was treated with heat. The low standard deviation supports this. The principle behind this method is that fat is extracted using a mixture of ethyl ether and petroleum ether. The extract is then dried and expressed as a percentage of fat by weight.
In the digestion step of the method the nitrogen is converted into ammonium using a catalyst and concentrated sulphuric acid at a high temperature. The problem is that once you have gotten your nifty new product, the proximate analysis laboratory manual gets a brief glance, maybe a once over, but it often tends to get discarded or lost with the original packaging. This process was repeated with the only variables being the amount of reagents; 5mL of ethanol, 15mL of diethyl ether and 15mL of petroleum. This may have contributed to the experimental error. Total fat content was determined using the Mojonnier method.