230
A. Ikehata
Fig. 9.16 Sample cells for powders and grains
Thus, sample setting is a key practice. In addition, to obtain a position average
spectrum, some NIR instruments have a rotating or sliding cell option.
9.2.1.5 Pastes
Various kinds of pastes, such as ground meat, mayonnaise, fermented soybean paste
(miso), and dough, are subjected to NIR measurement. Commercially available cells
for the DR measurement of powders and grains are also useful for pastes. If it is
possible to create a smooth surface, a paste sample packed in a polyethylene bag
can be used as a measuring object. Smooth viscose paste samples, e.g., mayonnaise
and butter, can be assessed using the transmittance method with a thin quartz cell
comprising a sandwich of two quartz plates and a spacer of known thickness.
9.2.2 Sample Pretreatments and Measurement Conditions
As previously described, sample pretreatment is often necessary for NIR
measurements. Some of them were already mentioned above, and examples of
sample pretreatments are presented in Chap. 15 (agricultural products), Chap. 16
(woods and soils), Chap. 17 (sugarcane), Chap. 18 (pharmaceutical applications),
Chap. 20 (medical applications), Chap. 21 (polymers), and Chap. 22 (on-line analysis). Various pretreatment methods have been used in NIR measurements, and a
number of instruments and equipment are commercially available. Pretreatment
methods may be divided into grinding, slicing, cutting, shredding, juicing, and
homogenizing. For some samples, moisture control is also important. Some of these
are described in different chapters. In addition, a detailed explanation about the
pretreatments is provided in Refs. [12, 13].
A. Ikehata
Fig. 9.16 Sample cells for powders and grains
Thus, sample setting is a key practice. In addition, to obtain a position average
spectrum, some NIR instruments have a rotating or sliding cell option.
9.2.1.5 Pastes
Various kinds of pastes, such as ground meat, mayonnaise, fermented soybean paste
(miso), and dough, are subjected to NIR measurement. Commercially available cells
for the DR measurement of powders and grains are also useful for pastes. If it is
possible to create a smooth surface, a paste sample packed in a polyethylene bag
can be used as a measuring object. Smooth viscose paste samples, e.g., mayonnaise
and butter, can be assessed using the transmittance method with a thin quartz cell
comprising a sandwich of two quartz plates and a spacer of known thickness.
9.2.2 Sample Pretreatments and Measurement Conditions
As previously described, sample pretreatment is often necessary for NIR
measurements. Some of them were already mentioned above, and examples of
sample pretreatments are presented in Chap. 15 (agricultural products), Chap. 16
(woods and soils), Chap. 17 (sugarcane), Chap. 18 (pharmaceutical applications),
Chap. 20 (medical applications), Chap. 21 (polymers), and Chap. 22 (on-line analysis). Various pretreatment methods have been used in NIR measurements, and a
number of instruments and equipment are commercially available. Pretreatment
methods may be divided into grinding, slicing, cutting, shredding, juicing, and
homogenizing. For some samples, moisture control is also important. Some of these
are described in different chapters. In addition, a detailed explanation about the
pretreatments is provided in Refs. [12, 13].