Sample Preparation Flashcards
(20 cards)
A complete ______requires severa consideration incuding
1.type of saple to collect
2. Wheter to collect grab samples, composite, or in situ samles
3. Whether the population is homogeneous or heterogeneous
4. Appropriate size for each sample
5. Number of sample to collect
Sampling plan
The ____ is reduced to a uniform particle size by passing it through the sieve
Gross sample
To ensure homogeneity the material from gross sample is processed so called
Coning and quartering
Inorganic solid samples have entrapped water so they must be dried before weighing .
T or F
True
In drying the samples prior to weighing, they are placed in a drying oven at ____ °C for 1 to 2 hrs
105-110°C
_____ or side reaction of the sample must be considered prior to drying
Decomposition
Thermally unstable sample can be dried in a ____
Desiccator
This can also be used to remove a fairly large amount of water from a sample that contains thermally labile material
Lyophilizer or freeze dryer
The process of incineration or destructing something at high temperature (525°C up) using muffle furnace
Dry ashing
Crucibles with maximum tamperature at 500°C
Pyrex
This crucible resembles quartz in their properties but then will have a tendency to crack with rapid temperature change
Porcelain
This crucible can widstand 1000°C; disposable, unbreakable
Quartz fiber
This type of crucible can widstand up to 1250°C and also resistant to halogens, acids but not alkali at high temperature
Quartz
This crucible is resistant to both acid and alkalis and are inexpensive but they are composed of Fe, Cr, and Ni which can be a possible cause of contamination
Steel
This crucible is very inert and are probably best overall but currently too expensive
Platinum
This is commonly used prior to specific mineral analysis
Wet digestion or wet ashing
Also known as aqua regia which dissolves Au and Pt
HCl:HNO3 (3:1)
If inorganic sample resist decomposition by digesting with acids or bases they are often brought into solution by fusing with a large excess of an alkali metal salt called
Flux
This is only the sample preparation technique that allows you to matrix match the standards and known that cover a wide range of materials
Fusion
This is well suited to prepare samples for ICP and AA analyses since unlike common acid digestion technique it allows complete digestion
Fusion
