sediment samples. These differences are dominantly the polar properties of the
sample (water—polar, sediment—low to non-polar) characterized by hydrophilicity
and lipophilicity, respectively, the concentration levels expected for the analytes
therein and the homogeneity or heterogeneity of the matrix. Similarity in terms of
sampling type can be observed for solid material. The sampling of a sedimentary
archive in wetlands is highly similar to the techniques applied on coal sampling in
open pit or underground mines. However, sampling needs to be adopted to the
individual sample type.
Independently from the sampling type some preconditions need to be taken into
account prior to any initial action. Any artificial contamination needs to be avoided.
Main contamination sources are dirty sampling instruments or parts of them as well
as already contaminated sample storage devices. Hence, it is important to preclean
carefully all equipment used for sampling and sample storage. Further on, one major
pitfall is to ignore immediate marking of the sample boxes for an unambiguous
assigning of sample and sample location, layer etc. As a further aspect, the size or
amount of a sample should be dimensioned to be as representative as possible and to
contain enough material for performing all planned analytical procedures. Normally,
a second sampling does not generate fully comparable material. Sample amount
depends also on further specific properties of the material. As an example, if loose
clastic sediments are sampled, then the sample has to contain enough matter within
each particle size to adequately represent the size distribution. Consequently, samples of coarse material need to be substantially larger than fine sediments.
2.1.1 Fossil Matter
With respect to fossil material, oil sampling is a simpler task. Normally, these
samples are taken on the oil fields, directly from the well. They often contain
water and suspended solid material in addition to the oil phase. Sampling and further
storage of oil samples are done in precleaned vessel (preferable glass ware). In order
to prevent the loss of volatiles it is required to close the sample vessels immediately
with a tight stopper. To take a representative sample, it is best to fill the bottle with
crude oil in front of the nozzle at the oil well collector.
The second important sample type are rocks and sediments containing a certain
amount of organic matter. Sampling procedure depends on the purpose of sampling,
characteristic of sediments and location of sediment. Collected samples have to be
undisturbed and representative of the whole rock or sedimentary system
(e.g. spanning the whole grain size spectrum). It is also important to prevent any
deterioration and contamination of the material during sampling.
One general sampling approach is coring. Several coring devices are in usage,
that allows to obtain a more or less undisturbed stratigraphic column. For exploring
geological archives covering long time periods on the level of hundred thousand to
million years, the required deep penetration of down to kilometers below ground is
achievable only by complex technical corers. Noteworthy, for many of such drilling
6
2 Sampling
sample (water—polar, sediment—low to non-polar) characterized by hydrophilicity
and lipophilicity, respectively, the concentration levels expected for the analytes
therein and the homogeneity or heterogeneity of the matrix. Similarity in terms of
sampling type can be observed for solid material. The sampling of a sedimentary
archive in wetlands is highly similar to the techniques applied on coal sampling in
open pit or underground mines. However, sampling needs to be adopted to the
individual sample type.
Independently from the sampling type some preconditions need to be taken into
account prior to any initial action. Any artificial contamination needs to be avoided.
Main contamination sources are dirty sampling instruments or parts of them as well
as already contaminated sample storage devices. Hence, it is important to preclean
carefully all equipment used for sampling and sample storage. Further on, one major
pitfall is to ignore immediate marking of the sample boxes for an unambiguous
assigning of sample and sample location, layer etc. As a further aspect, the size or
amount of a sample should be dimensioned to be as representative as possible and to
contain enough material for performing all planned analytical procedures. Normally,
a second sampling does not generate fully comparable material. Sample amount
depends also on further specific properties of the material. As an example, if loose
clastic sediments are sampled, then the sample has to contain enough matter within
each particle size to adequately represent the size distribution. Consequently, samples of coarse material need to be substantially larger than fine sediments.
2.1.1 Fossil Matter
With respect to fossil material, oil sampling is a simpler task. Normally, these
samples are taken on the oil fields, directly from the well. They often contain
water and suspended solid material in addition to the oil phase. Sampling and further
storage of oil samples are done in precleaned vessel (preferable glass ware). In order
to prevent the loss of volatiles it is required to close the sample vessels immediately
with a tight stopper. To take a representative sample, it is best to fill the bottle with
crude oil in front of the nozzle at the oil well collector.
The second important sample type are rocks and sediments containing a certain
amount of organic matter. Sampling procedure depends on the purpose of sampling,
characteristic of sediments and location of sediment. Collected samples have to be
undisturbed and representative of the whole rock or sedimentary system
(e.g. spanning the whole grain size spectrum). It is also important to prevent any
deterioration and contamination of the material during sampling.
One general sampling approach is coring. Several coring devices are in usage,
that allows to obtain a more or less undisturbed stratigraphic column. For exploring
geological archives covering long time periods on the level of hundred thousand to
million years, the required deep penetration of down to kilometers below ground is
achievable only by complex technical corers. Noteworthy, for many of such drilling
6
2 Sampling