WO2009130539A1

WO2009130539A1 - Apparatus for analysing solid, particulate material and method of analysing using the apparatus

Info

Publication number: WO2009130539A1
Application number: PCT/IB2008/051552
Authority: WO
Inventors: Vejay Jekmohan
Original assignee: Gea Process Engineering (Nps) Ltd.
Priority date: 2008-04-23
Filing date: 2008-04-23
Publication date: 2009-10-29

Abstract

The apparatus is intended for analysing solid, particulate materials and comprises a housing (1) defining an axial direction, and a probe (2) in¬ cluding an analytical sensor (3). The probe (2) is located in the housing (1) and may be introduced into the solid, particulate material. The mate¬ rial to be analysed is introduced through an inlet duct (4) and flows through a sampling cup (6) located downstream from the inlet duct (4). The sampling cup (6) has an inner surface defining a sample space (7) in fluid communication with an exit port (8) of the sampling cup (6). An outlet duct (9) is located downstream from the sampling cup (6), the outlet duct (9) being in fluid communication with the exit port (8), In order to perform static and/or dynamic analyses on the material, the probe (2) is displaceable in the axial direction between a first extreme position in which the displaceable probe (2) is located at a distance from the sampling cup (6) and the analytical sensor (3) is retracted from the sample space (7), and a second extreme position in which the displace¬ able probe (2) blocks the exit port (8) of the sampling cup (6) and the analytical sensor (3) is located within the sample space (7).

Description

Apparatus for analysing solid, particulate material and method of analysing using the apparatus

The present invention relates to an apparatus for analysing solid, particulate materials, comprising a housing defining an axial direction, and a probe including an analytical sensor, said probe being located in said housing and being adapted for introduction into the solid, particulate material. The invention also relates to methods for analysing a solid, particulate material using the apparatus. Within the pharmaceutical industry there is an increasing interest in obtaining better data about manufacturing processes, for example by being able to make measurements on pharmaceutical ingredients directly during their manufacture and to get more thorough data faster than what may be obtained by subtracting samples from a process train and analysing the samples off-line. Such interests exist not only from the point of view of the manufacturers of pharmaceuticals with the intention to increase product quality and process efficiency, but have also been formulated as a set of guidelines by the Food and Drug Administration (FDA) in the USA. The FDA uses the term "Process Analytical Tech- nology" (PAT), and in their Guidance for Industry regarding PAT (dated September 2004), it is stated that "the Agency considers PAT to be a system for designing, analysing, and controlling manufacturing through timely measurements (i.e., during processing) of critical quality and performance attributes of raw and in-process materials and processes, with the goal of ensuring final product quality. It is important to note that the term analytical in PAT is viewed broadly to include chemical, physical, microbiological, mathematical, and risk analysis conducted in an integrated manner. The goal of PAT is to enhance understanding and control the manufacturing process, which is consistent with our current drug quality system: quality cannot be tested into products; it should be built- in or should be by design. Consequently, the tools and principles described in this guidance should be used for gaining process understanding and can also be used to meet the regulatory requirements for validating and controlling the manufacturing process." In the case of pharmaceutical or other manufacturing processes optical or electromagnetic methods are highly appropriate for analysis of solid, particulate materials. Such methods, based on for example photometric, spectrophotometric or image analysis of powders, bulk ma- terials, granules and the like, may be employed directly on materials, and appropriate analytical probes may be integrated in the manufacturing equipment.

An apparatus for electromagnetic spectrum analyses of a material is described in WO 2007/009522. This document describes a probe for the photometric, spectrophotometric or image analysis of powder, bulk material, granules and the like, with the measuring probe being arranged in a housing, with at least one radiation or light measuring element, a measuring window which is arranged in the path of rays in a wall of the housing, and with at least one detection element for the analysis, the measuring probe being formed and guided displaceably in such a way that at least part of the housing in which the measuring window is located enters through an opening into the product space in which the material to be analysed is located, for the analysis. This apparatus is suited for analyses employing a corresponding arrangement of light guides, such as for example reflection/remission or transreflection (UV, VIS, NIR, IR), fluorescence or laser induced fluorescence (LIF), bio- or chemiluminescence or Raman spectroscopy. The apparatus may comprise a transmitting light guide, and the detection element may comprise a receiving light guide; the light guides may be arranged in bundles. This apparatus allows for carrying out dynamic analysis of the material; however, the analysis is performed on a random part of the flow of the particulate material passing the probe.

With this background, it is an object of the present invention to provide an apparatus by which it is possible to perform controlled, dy- namic in-line sampling analyses on the material, and by which it is furthermore possible to perform static analysis of the material.

This and further objects are met by an apparatus for analysing solid, particulate materials, comprising a housing defining an axial direction, and a probe including an analytical sensor, said probe being located in said housing and being adapted for introduction into the solid, particulate material, said apparatus being characterized in that it further comprises an inlet duct for solid, particulate material, a sampling cup located downstream from the inlet duct and having an inner surface defining a sample space in fluid communication with an exit port of the sampling cup, an outlet duct located downstream from the sampling cup, said outlet duct being in fluid communication with said exit port, wherein the probe is displaceable in the axial direction between a first extreme position in which the displaceable probe is located at a distance from the sampling cup and the analytical sensor is retracted from the sample space, and a second extreme position in which the displaceable probe blocks the exit port of the sampling cup and the analytical sensor is located within the sample space.

By providing the apparatus with an inlet duct and an outlet duct for the solid, particulate material to be analysed, in combination with a sampling cup and a displaceable probe, in-line analyses of the material in the flow may be carried out with minimum interference with the ongoing process. Positioning the displaceable probe in the sample space allows the analytical sensor of the probe to perform dynamic analyses of the material in the sampling cup on a controlled part of the flow. In the first extreme position, the probe does not interfere with the flow of material at all; in the second extreme position, the material collects in the sample space. In this position, static analysis is carried out on the material collected in the sample cup. When the analyses have been carried out, the probe may be displaced again towards the first extreme position, thus allowing the material collected in the sampling cup to flow out of the exit port and further out through the outlet duct. Together, the probe and the sampling cup hence act as a valve in the flow of material. In an advantageous embodiment, said sampling cup has an outer surface defining an overflow conduit, said overflow conduit being in fluid communication with the outlet duct. This design of the sampling cup ensures that the flow of material passing through the apparatus will not be significantly hindered. Any hindrance to the mass flow through the exit port created by introducing the probe in the sample space will simply direct the flow of material into the overflow conduit. By means of the overflow conduit, the analytical sensor of the probe may be held within the sample space for a prolonged time, as surplus material will just flow past the sampling cup, through the overflow conduit and fur- ther to the next operation unit via the outlet duct.

Preferably, the housing is essentially vertically arranged and the inlet duct is located in an upper section of the housing and the sampling cup in a lower section of the housing. This implies that a solid, particulate material entering the housing via the inlet duct will be pulled by gravitational forces towards the sampling cup defining the sample space.

In a preferred embodiment, the probe is adapted to be located in an intermediate position, in which the analytical sensor is located within the sample space and there is fluid communication between the sample space and the exit port. By this feature it is possible to allow for dynamic, in-flow analyses to be carried out, in addition to the static analyses carried out with the probe in the second extreme position.

In a further preferred embodiment, the probe has a tip which has a conically shaped outer surface, and the inner surface of the sampling cup has a conical shape corresponding to the shape of the tip of the probe. This design provides an option to control the flow of particulate material passing from the sampling cup to the exit port using a mechanism similar to that of a needle valve. Thus, the flow through the exit port will be dependent on the position of the probe in the sampling cup. Preferably, the sampling cup is concentric with respect to the axial direction of the housing. In this area of the housing, the flow of material is even and reliable.

The analyses may be carried out in any suitable manner using any suitable technique. For instance, the analytical sensor may be adapted for optical analysis within the electromagnetic spectrum. In a further development of this embodiment, the probe comprises a transmitting light guide, a receiving light guide, a measuring window, a deflecting mirror, and wherein the housing comprises a calibrating element, so that the measuring window may be said to represent the "analytical sensor"; in this embodiment the housing of the apparatus may also be fitted with a calibrating element for calibrating the analytical sensor. Calibration may take the form of white balancing using an appropriate white standard calibration element, or the element may be a black standard calibration element or another type of calibration element as are well known within the art. Preferably, said apparatus further comprises a light source and a fibre-optic collector. In that case, the optical analysis is performed within the infrared or the near-infrared (NIR) region of the electromagnetic spectrum. It is most advantageous if the optical analysis is performed in a reflective, transmissive or transflective mode.

In order to make it possible to evaluate any difference between the in-line analyses with more traditionally acquired values, a cross- validation sampler is provided downstream of the sampling cup. By providing the cross-validation sampler in this manner, it is possible to ana- lyse the very same sample analysed in the sampling cup as in the subsequent analyses on the basis of the cross-validation sampler.

The invention also relates to a method for analysing a solid, particulate material using an apparatus according to the invention, and use of the apparatus. The invention will be described in more detail below by means of examples of embodiments with reference to the schematic drawing, in which

Fig. Ia shows an apparatus in an embodiment of the invention with the probe in an initial or 'parked' position; Fig. Ib shows the apparatus of Fig. Ia set for static sampling mode; and

Fig. Ic shows the apparatus of Fig. Ia set for dynamic or in-flow sampling mode.

The apparatus according to the invention is illustrated schemati- cally in Fig. 1 and comprises a housing 1 with a probe 2 including an analytical sensor 3. The apparatus has an inlet duct 4 for introducing solid, particulate material 5 to be analysed into the apparatus.

In particular, the material to be analysed is solid, particulate material processed in pharmaceutical manufacturing, though the appara- tus may be of use in other fields as well. In the context of the invention such materials comprise powders, bulk materials, granules, granulates and the like. These materials generally appear "dry" although they may contain water or other solvents in their structures. The apparatus will typically be integrated following an operational step involving blending, drying, pressing, coating, granulating, crushing, grinding or the like of pharmaceutical ingredients. The apparatus may be relevant at any stage in the manufacturing process where such unit operations are employed.

The inlet duct 4 is in fluid communication with a sampling cup 6 which is located downstream from the inlet duct 4 with respect to the flow of solid, particulate material 5 from the inlet duct 4. In the embodiment shown, the apparatus is arranged substantially vertically, i.e. the flow of material is subjected to gravity and flows in a generally vertical axial direction of the housing. The sampling cup 6 is located in a lower section of the housing 1, whereas the inlet duct 4 is located in an upper section of the housing 1. In the embodiment shown, the sampling cup 6 is concentric with respect to the axial direction of the housing, and the inlet duct 4 extends at an angle to the axial direction. However, other configurations are conceivable. For instance, the sampling cup of the in- vention is not limited to circular cross-sections, and other shapes, such as polygonal, ellipsoidal, rectangular etc., are also contemplated. The inner surface of the sampling cup 6 defines a sample space 7, wherein the solid, particulate material 5 may be analysed using the analytical sensor 3. The sampling cup may be connected to the housing 1 in any suitable manner. In one embodiment the sampling cup 6 is fixed to a circular member which in turn is attached to the wall of the housing 1 and held concentrically in the housing 1 using e.g. three attachment rods. This assembly may be installed in between a tri-clover connection for easy removal and cleaning of the sampling cup 6. The tip of the displaceable probe 2 will generally be shaped so as to match the inner surface of the sampling cup regarding its shape. For example, when the concentric sampling cup has a conically shaped inner surface, the tip of the probe will be shaped as a cone with dimensions similar to that of the inner surface. Thus, when the probe is placed in the lower extreme position the fit between the tip of the probe with the sampling cup will prevent a flow of particles out of the sampling cup through the exit port, and thereby directing the flow of particles to the overflow conduit. The "probe-sampling cup" pair can therefore be said to perform the function of a needle valve regarding the flow of solid, particulate material through the apparatus, and the tip of the probe may be regarded as a powder flow controller.

Activation and movement of the displaceable probe 2 may be achieved by any suitable means, such as for example pneumatic actua- tion or by a step motor; other means are well-known in the art and conceivable to the skilled person.

It is noted that the term "analytical sensor" as used in the present application refers to an element capable of collecting data from a sample. The data may be based on direct observation of a sample using appropriate means, or the data may be created by subjecting the sample to conditions producing observable data, such as exposing the sample to light within the infrared spectrum. In this latter case, the "analytical sensor" may also comprise the necessary means to subject the sample to the relevant conditions. In one embodiment of the invention the probe comprises transmitting and receiving light guides for exposing a sample to light and collecting light reflected by or transmitted through the sample. In the terms of the present invention a "probe" may generally be regarded as an analytical sensor designed for obtaining data within an apparatus without the need to extract physical samples for off-line analysis or otherwise remove material. This mode of analysis may also be referred to as "in-line" or "on-line". The probe of the present invention is located within a housing, in which housing it is displaceable between a first and a second extreme position. In one embodiment the housing of the apparatus is arranged in an essentially vertical orientation, and in this embodiment the "first extreme position" may also be referred to as the "upper extreme position". Likewise, the "second extreme position" of this embodiment may also be referred to as the "lower extreme position". Hereinafter "first extreme position" and "upper extreme position" are used interchangeably, and as are "second extreme position" and "lower extreme position", even though the housing may be in a non- vertical orientation. As will be described in further detail below, the concentric sampling cup 6 and thereby also the sample space 7 is of a sufficient size to withhold enough material for obtaining data using the ana- lytical sensor 3. The sample space 7 is in fluid communication with an exit port 8 of the sampling cup 6 through which solid, particulate material 5 may enter into an outlet duct 9. On the outer side of the sampling cup 6, seen in the radial direction, an overflow conduit 10 is defined by the space between the outer surface of the concentric sampling cup 6 and the inner surface of the housing 1. The function of the overflow conduit 10 will be described in further detail below. When the sample space 7 becomes filled with solid, particulate material 5 the overflow conduit 10 will ensure that all solid, particulate material 5 leaves the apparatus through the outlet duct 9, the flowing material thus overflowing into the next unit operation.

Furthermore, the apparatus may also comprise a cross- validation sampler 11 for extracting physical samples for off-line analysis for validating the data obtained from the analytical sensor 3. Such offline analyses may offer a direct correlation between wet-chemical ana- lytical methods and the analytical method, e.g. near-infrared (NIR) spectral analysis, employed in the apparatus. Relevant wet-chemical techniques for correlation with analysis in the apparatus could for example be HPLC, mass spectrometry, dissolution assays, microscopic analyses, biochemical assays, microbiological analyses or biological analyses. The cross-validation sampler 11 has a sample cavity 14 for collecting solid, particulate material. This sample cavity 14 may be set up to collect material from the exit port 8 of the sampling cup 6. The cross-validation sampler 11 may be inserted into the process stream via an inner pipe shield 15 which inner pipe shield 15 prevents material from the overflow conduit 10 from filling up the sample cavity 14 during insertion into the housing 1 of the apparatus. Thus, in this embodiment only material directly from the sampling cup 6 will be collected with the cross-validation sampler 11. Following a static analysis in the apparatus (as explained in further detail below) a sample of particles corresponding to those ana- lysed with the analytical sensor 3 may be collected by retracting the probe 2, thereby allowing a flow of particles out of the sampling cup 6 via the exit port 8. Thus, using the cross-validation sampler 11 the design of the apparatus allows for collection of physical samples corre- sponding exactly to those analysed with the analytical sensor 3 whether operating in a static or dynamic mode.

The term "sample" should, in the context of the present invention, be understood in a broad sense covering both a physical and an abstract aspect. Thus, "sample" or "sampling" may refer to a physical sam- pie, such as of a solid, particulate material, or the act of extracting this sample from the apparatus, respectively, or "sample" or "sampling" may refer to data obtained from a sample or the act of obtaining the data, respectively. Such data could be particle size, mass flow rate, temperature, moisture content, content of solvent, IR-spectra etc. In the embodiment shown of the apparatus according to the invention is designed for simple integration into a manufacturing process and has a single inlet duct for solid, particulate material and a single outlet duct for conducting the material into a subsequent unit operation. During the in situ analysis in the apparatus the solid, particulate material will be generally unaffected by the analysis (i.e. the analysis is nondestructive). In this embodiment the apparatus will be fitted with standard connections for connecting to tubes from or to other unit operations.

Data collected during analyses in the apparatus may be further processed by statistical analysis and/or for presenting to an operator using a data processing unit or PAT analyser 12. This data processing unit or PAT analyser 12 may be an integrated part of the apparatus, or the data may be supplied to an external unit for processing. Multivariate analysis techniques, such as principal component analysis (PCA), princi- pal component regression (PCR), partial least squares (PLS) modelling are relevant statistical methods for analysing data obtained in the apparatus, though other techniques will be known to a person skilled in the art.

The apparatus may be equipped with an inspection port 13 for visual observation of the processing within the apparatus. Visual observation may also be used as a tool for cross-validation of the employed analytical methods, and to ensure the analyses are conducted under appropriate conditions. Observations from the inspection port 13 may be used for correlating the level of solid, particulate material in the sample 7 with the flow rate employed in the process thereby ensuring that the analytical sensor 3 is in analytical proximity of the solid, particulate material. This correlation is particularly relevant for conducting dynamic or in-flow analyses and for programming the CPU for automated analyses. Typical manufacturing processes employed within the pharmaceutical field are of a continuous nature and may run for extended periods of time, e.g. 60 hours or more. Therefore, an apparatus for carrying out so-called auto-analysis may be provided. Such an apparatus may comprise a timing device, a sensor switch for monitoring the position of the probe relative to the first and second extreme positions, and a central processing unit (CPU) for collecting data from said timing device and from said sensor switch and of controlling the position of the probe. The CPU may allow for automated analyses in the apparatus; the CPU will receive data from the timing device and the sensor switch regarding analy- sis history of the process and the position of the probe at any given time, respectively, and the CPU may use this data to perform automated analyses according to a programmed sequence of events.

Such an apparatus may advantageously be set up for conducting automated analyses according to a predetermined programme, or according to an ad-hoc scheme dependent on data recorded in the apparatus. In this embodiment the apparatus comprises a timing device, which timing device monitors events in the apparatus and provides a temporal label for the events. The events may be analyses, changes in the position of the probe or changes in process parameters. The appara- tus also comprises a sensor switch, which sensor switch monitors the position of the probe relative to the first and second extreme positions. The apparatus is further equipped with a central processing unit (CPU) for collecting data from the timing device and from the sensor switch, and for using these data to conduct automated analyses (i.e. move the probe 2 and employ the analytical sensor 3) according to a relevant programme. The timing device may be integrated with the CPU. A programme for analysis generally contains three basic positional settings for the probe 2, i.e. the parked position according to Fig. Ia, the static analysis position according to Fig. Ib, and the dynamic analysis position according to Fig. Ic. The parked position may be regarded as the "default position" from which the probe 2 is moved at set intervals into the static or dynamic analysis position for a sufficient period of time to perform an analysis. Data collected by the analytical sensor 3 is sent to the data processing unit or PAT analyser 12, and a temporal label linked to the relevant event is provided by the timing device to the CPU. The probe 2 will then return to the default position. The programme may be repeated periodically throughout the current process, or the programme may be set to perform a set number of analyses. The CPU may also be in communication with the data processing unit 12, so that the CPU can be programmed to respond to an analysis result provided by the data processing unit 12 to the CPU. For example, an analysis result may lead to an increase or decrease in the frequency of analysis during the manufacturing process, or a given result may trigger an immediate static or dy- namic analysis. The CPU may even be programmed to change operational parameters in the manufacturing process upstream of the analysis in the apparatus.

As mentioned in the above, the apparatus according to the invention may be utilized within any field of technology involving the proc- essing of solid, particulate material, and the apparatus will most often be inserted between two production units. However, the apparatus may also be positioned at other locations in for instance a processing plant. Use of the apparatus is thus foreseen in connection with operation units, continuous or batch, including powder transfer arrangements, blending devices, fluid bed drying, fluid bed granulation, compacting granulation, coating, spray drying or the like.

In the following, operation of the apparatus according to the invention will be described in further detail.

In Fig. Ia the displaceable probe 2 is located in the first or up- per extreme position, in which the analytical sensor 3 is not in contact with the solid, particulate material 5. This setting may also be referred to as the "parked position". In this setting the flow of the solid, particulate material 5 will generally pass unhindered through the concentric sam- pling cup 6 and leave via the outlet duct 9.

Fig. Ib shows the second or lower extreme position of the probe 2. In this position the flow of solid, particulate material 5 through the exit port 8 is prevented by the probe 2 which blocks the exit port 8. The analytical sensor 3 will be in analytical proximity of solid, particulate ma- terial 5 in the sample space 7 which material cannot leave through the exit port 8 so that analyses can be performed under static conditions. Excess solid, particulate material 5 will be directed into the overflow conduit 10 and subsequently into the outlet duct 9.

When the displaceable probe is in the lower extreme position and the exit port of the sampling cup thereby blocked by the probe, the sampling cup will become filled with material from the inlet duct, until a point where the material will start flowing into the overflow conduit. With the analytical sensor in the sample space it will now be possible to perform static analyses of the solid, particulate material retained in the sampling cup and therefore in analytical proximity of the analytical sensor.

Material flowing into the overflow conduit from the sampling cup will subsequently enter the outlet duct. Thus, at any time when a flow of particulate material is entered into the apparatus via the inlet duct, the overflow conduit will ensure that the full volumetric stream of material will exit the apparatus via the outlet duct.

By retracting the probe 2 slightly to an intermediate position, as illustrated in Fig. Ic, a controlled flow of solid, particulate material 5 from the sample space 7 into the exit port 8 will be allowed. By using the probe 2 as a powder flow controller, a sufficient level of solid, particulate material 5 in the sample space 7 can be retained so as to keep the analytical sensor 3 in the sample space 7 within analytical proximity of the solid, particulate material 5. Thus, in this setting it is possible to conduct analyses under dynamic or in-flow conditions. The mass flow rate during analysis through the sampling cup 6 may be sufficient to allow all solid, particulate material 5 entered into the apparatus to leave the sampling cup 6 via the exit port 8. However, in certain regimes of operation it may be relevant to limit the mass flow rate leaving the sampling cup 6 through the exit port 8 so that part of the flow will be directed into the overflow conduit 10. Thus according to the invention, dynamic or in-flow analyses may be conducted at any fractional distribution of flow between the exit port 8 and the overflow conduit 10. Under these conditions, the displaceable probe may be positioned such that the analytical sensor is still located in the sample space and in analytical proximity of particulate material flowing through the sampling cup to the exit port. Thus, it is possible to perform analyses in a dynamic or in-flow mode.

By retracting the displaceable probe to the upper extreme position to attain the position shown in Fig. Ia, the analytical sensor will be withdrawn from the sample space, allowing an uninterrupted flow of particulate material through the sampling cup. In this position the analytical sensor will not be in contact with solid, particulate material passing through the apparatus. The apparatus of the present invention may also comprise a cleaning or flushing sub-chamber, such as that described in WO 2007/009522 (the contents of which are incorporated by reference). In this case the upper extreme position will be located within the cleaning sub-chamber allowing cleaning of the measuring window while preventing exposure of the analytical sensor to the solid, particulate material being analysed. The invention should not be regarded as being limited to the embodiments shown and described in the above but various modifications are conceivable to the person skilled in the art.

Claims

P A T E N T C L A I M S

1. An apparatus for analysing solid, particulate materials, comprising a housing defining an axial direction, and a probe including an analytical sensor, said probe being located in said housing and being adapted for introduction into the solid, particulate material, c h a r a c t e r i z e d in that it further comprises an inlet duct for solid, particulate material, a sampling cup located downstream from the inlet duct and having an inner surface defining a sample space in fluid communication with an exit port of the sampling cup, an outlet duct located downstream from the sampling cup, said outlet duct being in fluid communication with said exit port, wherein the probe is displaceable in the axial direction between a first extreme position in which the displaceable probe is located at a distance from the sampling cup and the analytical sensor is retracted from the sample space, and a second extreme position in which the displaceable probe blocks the exit port of the sampling cup and the analytical sensor is located within the sample space.

2. An apparatus according to claim 1, wherein said sampling cup has an outer surface defining an overflow conduit, said overflow conduit being in fluid communication with the outlet duct.

3. An apparatus according to claim 1 or 2, wherein the housing is essentially vertically arranged and the inlet duct is located in an upper section of the housing and the sampling cup in a lower section of the housing.

4. An apparatus according to any one of the preceding claims, wherein the probe is adapted to be located in an intermediate position, in which the analytical sensor is located within the sample space and there is fluid communication between the sample space and the exit port.

5. An apparatus according to any one of the preceding claims, wherein the probe has a tip which has a conically shaped outer surface, and the inner surface of the sampling cup has a conical shape corresponding to the shape of the tip of the probe.

6. An apparatus according to any one of the preceding claims, wherein the sampling cup is concentric with respect to the axial direction of the housing.

7. An apparatus according to any one of the preceding claims, wherein the analytical sensor is adapted for optical analysis within the electromagnetic spectrum.

8. An apparatus according to claim 7, wherein the probe comprises a transmitting light guide, a receiving light guide, a measuring window, a deflecting mirror, and wherein the housing comprises a cali- brating element.

9. An apparatus according to claim 7 or 8, wherein said apparatus further comprises a light source and a fibre-optic collector.

10. An apparatus according to any one of claims 7-9, wherein the optical analysis is performed within the infrared or the near-infrared (NIR) region of the electromagnetic spectrum.

11. An apparatus according to claim 10, wherein the optical analysis is performed in a reflective, transmissive or transflective mode.

12. An apparatus according to any one of the preceding claims, wherein a cross-validation sampler is provided downstream of the sam- pling cup.

13. A method for analysing a solid, particulate material using an apparatus according to any one of the preceding claims, wherein the axially displaceable probe is positioned to hold the analytical sensor in the sample space and keeping it in analytical proximity of solid, particu- late material in the apparatus.

14. A method according to claim 13, wherein the axially displaceable probe is positioned in the second extreme position, and the analysis is performed in a static mode.

15. A method according to claim 13, wherein the axially dis- placeable probe is positioned away from the second extreme position, and the analysis is performed in a dynamic or in-flow mode.

16. A method according to claim 13, wherein the apparatus is utilised for conducting automated analyses according to a programmed series of events comprising dynamic and/or static sampling of a solid, particulate material.

17. Use of the apparatus according to any one of claims 1-12 in connection with operation units, continuous or batch, including powder transfer arrangements, blending devices, fluid bed drying, fluid bed granulation, compacting granulation, coating, spray drying or the like.