CN218629175U - Sample preparation system - Google Patents

Abstract

The utility model provides a sample preparation system, include: a plurality of parallel extraction channels; a gas supply unit for supplying gas to the respective sample cells, the gas supply unit comprising: a first supply line; a plurality of parallel second supply lines branching off from the first supply line, each of which second supply lines can be fluidically connected to a corresponding one of the extraction channels, the second supply lines being situated between the first supply line and the extraction channel, viewed in the direction of flow of the gas; a first flow control device disposed on the first supply line to control a total flow rate of the gas supplied to the plurality of extraction channels; a plurality of second flow rate limiting devices, each of which may be disposed on a corresponding one of the second supply lines and includes a resistance providing structure configured such that a difference between flow rates of the gases flowing into the respective extraction channels is less than a predetermined threshold value. With the sample preparation system, gas can be made to flow into each extraction channel at a uniform flow rate.

Description

Sample preparation system

Technical Field

The utility model relates to a fluid system, especially a sample preparation system. The fluid system comprises a plurality of parallel fluid channels, such as extraction channels in a solvent extraction system, and a gas supply unit for supplying fluid, mainly gas, to the fluid channels.

Background

Currently, multichannel technology is often employed in a variety of devices or instruments including fluidic systems. The multi-channel technique has the significant advantage that the throughput per unit time can be increased by a plurality of channels in parallel or simply multipath, or that different requirements, for example different throughputs, for different users of the same device can be met more flexibly.

As an example, in sample preparation systems, particularly those that utilize solid-liquid extraction techniques, the efficiency of sample preparation can be greatly enhanced by means of multi-channel extraction, multi-channel evaporation, or a combination of both. In the case of multi-channel extraction, a fluid, such as a liquid solvent, a gas, or a mixture of both, may be supplied to the sample cell within each of the plurality of extraction channels, such that the analyte in the sample is dissolved in the liquid solvent in the sample cell, thereby extracting the analyte. In the case of multi-pass evaporation, the liquid solvent containing the analyte in a plurality of evaporation containers arranged in parallel is evaporated.

Further, for multi-channel extraction, it is desirable that the volume of fluid, e.g., gas, supplied to the sample cell in each extraction channel is the same. This is advantageous for multi-channel extraction, as it allows the extraction conditions to be kept more consistent from cell to cell, resulting in closer extraction recovery and shorter overall extraction time from cell to cell. In addition, supplying the sample cells in the respective extraction channels in equal amounts (e.g., equal volumes of the gas-liquid mixture) in a preset supply cycle generally means that the duration of the supply is the same for each sample cell. This can make temperature changes, pressure changes, static extraction times, etc. substantially uniform for each sample cell, so that an optimal overall chemical-dynamic balance can be achieved for a plurality of sample cells, thereby achieving high extraction recovery. For multi-pass evaporation, it is also desirable that the solvent in each evaporation pass reaches its evaporation end point as simultaneously as possible, thereby reducing the overall evaporation completion time.

Despite the above advantages of multi-channel technology, there may be problems with non-uniform fluid flow or velocity between each parallel channel in an actual product. Even if the design attempts to ensure that the channels are identical in configuration (e.g., identical fluid line type and size), such non-uniform flow rates may be due to manufacturing variations in the lines, fluid connections or other connections, the sample wells themselves, small variations in the amount of sample in the sample wells, undesirable or unavoidable pressure non-uniformities anywhere in the flow path, and the like.

In order to control the fluid flow, for example the flow supplied to the sample cell, more precisely, flow control devices are usually arranged on the flow path manifold (or total flow path) upstream of the multiple channels, which flow control devices can usually regulate the total flow supplied to the multiple channels.

Secondly, in order to control the flow rates of the individual channels as equally as possible, it is known to arrange further flow control devices downstream of the flow control device. However, if these flow control devices are arranged separately on each of the branch lines in a multi-channel, the cost of the fluid system is very high. However, if one flow control device is not provided in each branch flow path, but an additional selectively connected flow distribution device is used to distribute the total flow to each branch flow path, it may be difficult to supply the fluids simultaneously to multiple paths.

To this end, there is always a need in the field of fluidics, and in particular in the field of sample preparation, for a solution that makes the fluid flow more uniform between multiple channels in a cost-effective manner.

SUMMERY OF THE UTILITY MODEL

The utility model provides a sample preparation system, this sample preparation system can include: a plurality of parallel extraction channels, each extraction channel may comprise a sample cell for placing a sample; a gas supply unit for supplying gas to the respective sample cells, the gas supply unit may include: a first supply line; a plurality of parallel second supply lines branching off from the first supply line, each of which second supply lines can be fluidically connected to a corresponding one of the extraction channels, the second supply lines, viewed in the flow direction of the gas, being able to be located between the first supply line and the extraction channel; a first flow control device disposed on the first supply line to control a total flow rate of the gas supplied to the plurality of extraction channels; a plurality of second flow rate limiting devices, each of which may be disposed on a corresponding one of the second supply lines, and the second flow rate limiting devices include a resistance providing structure configured such that a difference between gas flow rates flowing into the respective extraction channels is less than a predetermined threshold value.

By means of the sample preparation system comprising the gas supply unit, in particular the resistance providing structure, a uniform flow of gas into the individual extraction channels is made possible, which makes it possible to make the extraction conditions of the sample cells in the individual extraction channels more uniform, thereby minimizing the multi-channel extraction time (and the subsequent possible evaporation time) on the one hand, and also achieving a consistently high level of extraction recovery between the individual extraction channels on the other hand.

Preferably, the first flow control device may be configured as a mass flow controller. The mass flow controller can accurately maintain the total flow of gas flowing into the plurality of parallel second supply lines at a preset value.

In particular, the resistance providing structure of the second flow restriction means may be configured to increase the flow resistance of the gas flowing through the corresponding second supply line by a factor of 10 to 100. The flow resistance of the second supply lines can be increased significantly by the resistance providing structure, thereby maintaining a substantially uniform flow rate between the respective parallel second supply lines.

In particular, the resistance providing structure of the second flow restriction means is configured to enable the predetermined threshold value to be 5% of the flow rate of gas flowing from one second supply line into the corresponding extraction channel. The flow resistance of the second supply lines can be increased significantly by the resistance providing structure, so that the difference between the flow rates of the respective parallel second supply lines reaches a very small value, and the flow rate distribution is made more uniform.

Advantageously, the resistance providing structure may comprise a portion of reduced internal diameter relative to the internal diameter of the conduit of the second supply conduit. A significant increase in the flow resistance in the pipeline can be achieved by the constriction. Preferably, the narrowing may comprise a tube section having an inner diameter of less than 0.2 mm, preferably less than 0.1 mm, more preferably less than 0.05 mm. For example, the inner diameter of the narrowest section of the constriction is less than 0.2 mm, preferably less than 0.1 mm, more preferably less than 0.05 mm.

Further, the resistance providing structure may include at least one curved portion. The bends help to achieve a significant increase in resistance over a shorter length than a straight-extending resistance providing structure, particularly a helical or serpentine line. It is to be understood that the resistance providing structure may also be a combination of having a narrowed portion and being in a non-linear configuration (i.e., including a bend).

Preferably, the resistance providing structure may comprise a porous structure, such as a powder sintered porous structure. With the resistance providing structure of the porous structure, a large increase in flow resistance (e.g., a shorter length and a smaller cross-sectional size) can be achieved in a compact structure. The porous structure enables the same degree of increase in flow resistance to be achieved with a very short (longitudinal) dimension compared to solutions with a small diameter constriction

In particular, a switching device for controlling the switching of the gas in the second supply line can also be arranged on the second supply line, the second flow-limiting device being arranged between the first flow-control device and the switching device.

The switching device can be used to more flexibly control the switching of the gas on and off the respective second supply line in order to better cooperate with other control strategies of the system. If the second flow restriction means is located closer to the first supply line, the problem that the flow resistance is difficult to rise quickly due to the small flow rate when the switching means is just opened can be avoided.

Advantageously, no mass flow controller may be provided between the first flow control means and the extraction channel. If no mass flow controllers are provided between the first flow control device and the extraction channel, in particular on the second supply lines, then a homogenization of the gas flow rates on the individual second supply lines and thus on the extraction channel can be achieved at low cost.

Drawings

Fig. 1 schematically shows a simplified schematic of a fluid system according to the prior art, wherein the fluid system comprises a gas supply line;

fig. 2 schematically shows a simplified schematic of a test flow path for testing a second flow restriction device of a sample preparation system according to the present invention;

fig. 3 schematically shows a simplified schematic of an embodiment of a sample preparation system according to the present invention, wherein the fluidic system comprises a gas supply line;

fig. 4 schematically illustrates a simplified schematic diagram of an embodiment of a resistance providing structure of a gas supply unit of a sample preparation system according to the present invention; and

fig. 5 exemplarily shows a fluidic system diagram of an embodiment of the sample preparation system according to the present invention.

List of reference numbers:

100. sample preparation system

111. A first supply line

111b-111e second supply line

112. Liquid solvent supply line

113. Solvent pump

114. First flow control device

115. Change-over valve

116. Switching device

116a-116e first through fifth switching devices

117. Mixing device

118. Pressure sensor

119. Second flow rate limiting device

119b-119e first to fourth air resistors

120. Porous structure

121. Pressure gauge

122. Sample cell

122b-122e first to fourth sample cells

124b-124e preheater

152. Gas source

154. A solvent container.

Detailed Description

The sample preparation system is described herein primarily with reference to gas-assisted solvent extraction techniques and apparatus therefor, but it will be appreciated that the sample preparation system of the present invention is not limited to application to such solvent extraction techniques, and may be, for example, any suitable technique for supplying gas to a flow channel to prepare a sample located within the flow channel. Furthermore, the sample preparation system of the present invention is not limited to the system that can perform extraction and evaporation, but can be a system, particularly an automated sample preparation system, that performs more functions including extraction and evaporation.

In the present invention, the term "sample" refers to a substance which, when not extracted, contains therein the chemical substance to be analyzed (or "analyte"). The sample is suitable for being put into the sample preparation system of the utility model, in particular to the sample cell of the extraction channel thereof.

In the present disclosure, the term "between …" refers to the positioning of devices or components in the flow path. Furthermore, the term "upstream/downstream of …" is also with reference to the direction of flow of the fluid, "upstream of …" means before it in the direction of flow, and "downstream of …" means after it in the direction of flow.

In the sample preparation system of the present invention, although it is possible to provide gas, liquid or a gas-liquid mixture to the extraction channel, the fluid supply mentioned in the present invention is mainly to supply gas to the extraction channel and thus to the sample cell located therein.

First, the present invention relates to a fluid system, which may include a plurality of parallel fluid channels. These fluid channels may be used to perform a given function. For example, when the fluidic system relates to a sample preparation system, the plurality of parallel fluidic channels may be extraction channels. The term "parallel" means here that the extraction channels are arranged in parallel with one another, and not in succession (in series). It is to be understood that parallel flow channels (e.g., extraction channels) refer to a structurally parallel arrangement, and that although the supply of gas to the flow channels is typically performed in parallel as a whole, the present invention does not preclude the possibility of not supplying gas to all of the plurality of parallel flow channels at some point in time.

In embodiments of the sample preparation system 100, each extraction channel may be configured to receive a sample cell, and a sample containing an analyte may be received in each sample cell. It should be noted that although the sample preparation system 100 of the present invention may actually include extraction channels that are not used to place sample wells, for ease of illustration, these extraction channels will not be counted herein as extraction channels within the meaning of the present invention. Furthermore, it should be understood that the sample has been placed in the sample cell is not a prerequisite for the utility model sample preparation system to achieve its inventive objectives. For example, it is not excluded that the sample may also be loaded into the sample cell as needed (one by one or together) during the sample preparation process.

It should be noted that the terms "cell", "chamber" and "column" are used interchangeably to describe the portion of the extraction channel described herein where the sample is placed. For example, the term "column" (e.g., sample column, packed column, extraction column, etc.) may be used to describe a sample cell having a cylindrical shape. The sample cell may include an inlet and an outlet, but should have a substantially closed structure so that the sample therein does not leak outwardly. It should be noted that although the extraction channel may also comprise other components than the sample cell, it may, when in the present invention and when flowing into the extraction channel, substantially correspond to flowing into the sample cell.

In the present invention, it is preferable that all the fluid devices, components, pipes, etc. associated with the above-described fluid passages are set to be the same or substantially the same, so as to reduce the difference in flow rate on each passage due to the difference in the fluid devices, components, pipes themselves as much as possible. It should be noted, however, that the achievement of the objects of the present invention is not impaired if there are unavoidable differences between the various fluidic devices, lines, components, etc. associated with the above-described fluidic channels.

According to the present invention, it is necessary to supply fluid to the above-mentioned plurality of parallel fluid channels, for example extraction channels, in order to extract analytes in the sample cell. In some advantageous embodiments, the addition of gas during solvent extraction can increase the efficiency of diffusion of the liquid solvent into the solid sample and the efficiency of extraction of the analyte from the solid sample. To this end, the liquid solvent and the gas may be combined together to form a mixture prior to flowing the liquid solvent into the sample cell. After entering the sample cell, the diffusion of this gas phase in the mixture can be several orders of magnitude higher than the liquid solvent phase. Thus, even if the gas itself does not dissolve the analyte, the addition of gas may still improve the overall mass transfer properties of the liquid solvent. Thus, the gas-assisted solvent extraction technique not only reduces the amount of solvent used, but it also allows extraction to be performed in a faster time frame. In addition to supplying a gas-liquid mixture, the sample preparation system 100 of the present invention may also include the possibility of supplying only gas to the individual extraction channels, for example by filling the sample cell with gas to bring the sample cell to a high pressure.

To this end, the sample preparation system 100 of the present invention may comprise a gas supply unit to supply gas to the sample cell in the respective fluidic channel, e.g. the extraction channel. The gas supply unit of the present invention may, but may not, include a gas source. In the case where no gas source is included, the gas supply unit may feed a gas, such as compressed nitrogen, from the gas source into the extraction channel.

The gas supply unit may include a first supply line 111 and a second supply line. A plurality of parallel second supply lines branch off from the first supply line 111. Therefore, in the present invention, the first supply line 111 may be referred to as a manifold, and the second supply line may be referred to as a branch line. A plurality of parallel second supply lines preferably branch off directly from the first supply line 111, although indirect branching off from the first supply line 111 is not excluded, for example there are further lines in between, but the latter is not preferred. The term "split" herein means that the first supply line is in fluid communication with each of a plurality of parallel second supply lines, which are not typically in fluid communication with each other.

It should be noted that in the present invention, there may be not only one first supply line 111, but when the gas supply unit has a plurality of first supply lines, a plurality of parallel second supply lines are branched from each first supply line 111, but this is not preferable. As shown in fig. 3, in a preferred embodiment, the gas supply lines comprise one first supply line 111 and four second supply lines 111b-111e (directly) branched therefrom, but the number of second supply lines may be two, three, or more than four, such as six, eight, etc.

Each of the plurality of parallel second supply lines of the present invention is fluidly connected to a corresponding one of the plurality of fluid passages, e.g., an extraction passage. When a sample cell 122 is disposed within the extraction channel, fluid in the second supply line may flow into the sample cell 122. Thus, the second supply line is located between the first supply line 111 and the fluid channel, as seen in the direction of fluid flow. In other words, the first supply pipe 111 is located upstream of the second supply pipe, and the fluid passage is located downstream of the second supply pipe, as viewed in the direction of fluid flow. It should be understood, however, that the upstream and downstream relationship of the fluid flow need only be satisfied, and that the first supply line 111 and the extraction channel need not be physically located on opposite sides of the second supply line.

The gas supply unit of the present invention further comprises a first flow control means 114 arranged on the first supply line 111 for controlling the total flow of fluid, mainly gas, supplied to the plurality of parallel second supply lines and thereby to the plurality of parallel fluid channels (e.g. extraction channels) in fluid communication with the second supply lines.

In the present invention, the gas on the first supply line 111, which is controlled by means of the first flow control device 114, normally flows in its entirety into all second supply lines branching off from the first supply line 111 (although it is not excluded that only some of the second supply lines flow into it), but generally no longer flows into other lines than these second supply lines, in order to ensure that the total flow of the gas, which is controlled or regulated by means of the first flow control device 114, can be distributed between a plurality of parallel second supply lines branching off from the first supply line 111.

The first flow control device 114 may be any suitable device capable of controlling the flow of fluid. In some embodiments, if the supplied fluid is a gas, the first flow control device 114 is preferably a Mass Flow Controller (MFC). The working principle of the mass flow controller is, for example: when fluid flows through the vibrating tube, a Coriolis force effect is generated on the vibrating tube, so that the two vibrating tubes generate torsional vibration, and therefore, two groups of signals with different phases are generated by coils arranged at two ends of the vibrating tube, and the difference of the two groups of signals is proportional to the mass flow of the fluid flowing through the sensor. In addition, when different fluid media flow through the sensor, the main vibration frequencies of the vibration tubes are different, and the density of the fluid media can be calculated according to the main vibration frequencies. In addition, a platinum resistor mounted on the vibrating tube can also indirectly measure the temperature of the fluid medium. Of course, the design principle and the internal structure of the mass flow controller of the present invention may not be limited thereto, and any controller capable of accurately measuring the flow rate of the fluid is within the scope of the present invention.

In one example of the prior art shown in fig. 1, in addition to the flow control devices on the manifolds, one flow control device, such as a mass flow controller, is provided on each of the branch fluid lines. The flow control device is used to control the flow of fluid on each of the branch flow paths. Since the mass flow controller controls the flow of fluid very precisely, if the flow rate of gas on the branch flow path is controlled to 50 ml/min by the mass flow controller, the flow of fluid flowing into one channel can be actually controlled to 50 ml/min, and the flow does not or substantially does not vary with the flow resistance in the channel. However, in order to make the flow rates or flow rates in the four parallel fluid channels the same, the prior art generally needs to provide four flow control devices to flexibly change the flow rates of the fluids in the fluid channels so that the flow rates flowing into the respective sample cells 122 are identical. This solution is very costly due to the complex construction of the mass flow controller.

In order to be able to solve the problem of distributing the total flow of gas more evenly between a plurality of parallel second supply lines at a lower cost, the gas supply unit of the present invention further comprises a plurality of second flow restriction devices 119, each second flow restriction device 119 being arranged on a corresponding second supply line, i.e. a second supply line is provided with a second flow restriction device 119. The second flow rate limiting means 119 of the present invention may be configured such that the flow rate difference between the respective second supply lines of the gas flow rate passing therethrough is smaller than a predetermined threshold value, or such that the difference between the gas flow rates flowing into the respective extraction passages is smaller than a predetermined threshold value.

In the present invention, the predetermined threshold value may be 5%, preferably 3%, of the fluid flow from one second supply line into the corresponding extraction channel. The fluid flow from a second supply line into the corresponding extraction channel can be a second supply line selected in advance for reference or comparison, but can also be an average value of the fluid flows from the second supply lines into the corresponding extraction channels.

The working principle of the second flow restriction device 119 of the present invention can be further analyzed by the test flow path shown in fig. 2. In the test example of fig. 2, assuming that there are four parallel extraction channels (although fig. 2 only shows one extraction channel), the gas flow rates of the four extraction channels can be expressed in units of X1, X2, X3, X4, for example in ml/min. When no flow restriction is provided, the gas flow into the extraction channel is approximately or almost the same as the gas flow on the fluid line before the extraction channel, because of the smaller flow resistance. A corresponding one of the flow restriction devices is disposed on the gas line in fluid communication with each extraction channel, and a pressure gauge 121 for measuring pressure in PSI min/ml is disposed between the flow restriction device and the extraction channel.

The following relationship exists between four extraction channels in parallel:

(R1+C1)*X1＝(R2+C2)*X2＝(R3+C3)*X3＝(R4+C4)*X4。

assuming that the variation between the flow resistances of the individual extraction channels does not exceed 50% of the measured values, the actual value of Ci can be Ci ± 0.5Ci. Max (Ci/(Ri + Ci) = 0.05) if it is to be achieved that the difference between the gas flows into the individual extraction channels is less than 5% of the flow. From this, ri =19Ci can be derived.

In order to achieve a smaller gas flow difference between the extraction channels, the flow resistance value to be provided by the second flow restriction means 119 can be deduced from the above formula. That is, the flow resistance of the fluid flowing through the corresponding second supply line can be increased by the second flow rate limiting device 119 of the present invention, for example, by a factor of 10 to 100, preferably by a factor of 20 to 50.

It will be appreciated that the second flow restriction device 119 of the present invention may be of any suitable construction, configuration, shape, size, etc. to provide a flow resistance to gas flowing through it, such that the flow resistance of fluid flowing through the corresponding second supply line is substantially increased, for example by an order of magnitude, particularly by a factor of 10 to 100. Advantageously, the second flow restriction means 119 may comprise a resistance providing structure. Preferably, the resistance providing structure enables a difference between the fluid flow rates flowing into the respective extraction channels to be less than 5%, in particular less than 3%, of the gas flow rate flowing from one second supply line into the corresponding extraction channel. It is noted that any form of resistance providing structure that can increase the flow resistance is within the scope of the present invention.

In theory, in the present invention, the gas flowing through each second supply line can reach the desired gas flow rate (for example, 50 ml/min) by means of the second flow rate limiting device 119, and the gas flow rates on the plurality of parallel second supply lines or extraction channels are substantially equal. As mentioned before, the difference in gas flow between the individual extraction channels or second supply lines may be less than 5% of the gas flow on a single channel or single line, i.e. the difference may be less than e.g. 2.5 ml/min.

In some embodiments, the resistance providing structure of the second flow restriction device 119 may comprise a porous structure, preferably a powder sintered porous structure 120, in particular a porous metal element, to achieve a substantial increase of the flow resistance in a very compact structure. As shown in fig. 4, when gas flows through the porous structure 120 of the resistance providing structure, the gas can flow more uniformly with little friction.

In other embodiments, the resistance providing structure may include a narrowed portion having a reduced or narrowed inner diameter relative to the inner diameter of the second supply conduit. For example, the narrowing may comprise a tube section having an inner diameter of less than 0.2 mm, preferably less than 0.1 mm, for example 0.05 mm. The narrowing may have a constant diameter, but may also have a non-constant diameter, for example a waisted shape with the narrowest section in the narrowing may for example have an inner diameter of less than 0.2 mm, preferably less than 0.1 mm, for example 0.05 mm.

In still other embodiments, the resistance providing structure may include at least one bend, such as an element configured in a spiral or serpentine shape, to significantly increase the flow resistance. Further, the length, flow cross-sectional shape, and the like of the resistance providing structure may be selected according to the magnitude of the flow resistance to be provided.

Preferably, the resistance providing structures of the second flow rate limiting devices 119 provided in the plurality of parallel second supply lines are the same as each other, but may be different. Regardless of the configuration of the resistance providing structures, the flow resistance provided by each resistance providing structure should be such that the flow resistance of each of the plurality of juxtaposed second supply lines is relatively high (i.e., significantly higher than the flow resistance provided by the second supply line, extraction channel, fluidic connector, etc. itself) so that the total flow can be evenly distributed among the individual extraction channels.

In particular, because a second flow restriction device 119 is provided for each second supply line, the sample preparation system 100 according to the present invention eliminates the need for a mass flow controller or other similar flow control device between the first flow control device 114 and the extraction channel.

Furthermore, according to the present invention, as shown in fig. 3, a switch device 116 for controlling on/off of the fluid in the second supply line is also disposed on the second supply line. Optionally, the second flow restriction device 119 is arranged closer to the first flow control device 114 than the switching device 116. If the switching device 116 is arranged closer to the first flow control device 114 or the first supply line 111 on the second supply line, then a flow resistance cannot be quickly built up on the second supply line when the switching device 116 is just opened, because the flow is very small. It is therefore preferred to arrange the second flow restriction means 119 between the first flow control means 114 and the switching means 116.

An exemplary embodiment of a sample preparation system 100 according to the present invention is explained below with reference to fig. 5. It should be noted, however, that the following examples are not limiting, but merely serve to illustrate one preferred embodiment of the sample preparation system 100, and in particular of its gas supply unit.

By way of example only, in gas-assisted solvent extraction techniques, it is advantageous to control the gas-liquid mixture ratio of the liquid solvent and the gas, as a mixture of both needs to be supplied to the sample cell. If the gas-liquid mixing ratio is not appropriate, the gas-liquid mixing is not uniform, and the extraction efficiency in the sample cell is undesirably reduced. To solve this problem, it is conceivable to supply a preset flow rate of gas to the sample cell to be mixed with the liquid solvent during the supply of the mixture of gas and liquid solvent.

First, the sample preparation system 100 of the present disclosure includes a first supply module that may, but may not, include a solvent source (e.g., a solvent container 154 containing a liquid solvent), a gas source 152 (e.g., a compressed nitrogen gas cylinder), devices or components directly associated with the solvent source and the gas source 152 (e.g., a gas source switch, a filter, a pressure sensor), and the like.

The first supply module of the sample preparation system 100 may include a gas supply unit. In the present invention, the gas supplied may be nitrogen, air or other suitable inert gas. The gas supply unit includes a first supply pipe 111 and five parallel branch pipes branched from the first supply pipe. Of these five branch lines, the second supply line 111b-111e is a four-way parallel branch line for distributing the total flow of gas from the first supply line 111 to the four subsequent extraction channels and hence the sample cells 122b-122e, while the second supply line 111a is separately used for other purposes, e.g., directly supplied to the switching valve 115 described below without being mixed with a liquid solvent. Of course, it is understood that the number of second supply lines may be less than or greater than five.

According to the present invention, a first flow control device 114, preferably a mass flow controller, may be arranged on the first supply line 111. During the supply of the mixture of the gas and the liquid solvent, the gas is supplied to the four sample cells 122b to 122e by means of the gas flow control device 114 at a predetermined flow rate (for example, 1 to 200 ml/min) to be mixed with the liquid solvent.

The first flow control device 114 may include an inlet and an outlet, the inlet of which may be in communication with the gas source 152 and the outlet of which may be in communication with the extraction channel. Typically, the inlet pressure of the first flow control device 114 is higher than the outlet pressure. Preferably, the outlet pressure of the first flow control device 114 is also maintained within a stable preset interval (e.g., 220-300 psi). Since the gas source 152 preferably provides pressurized gas, the inlet pressure of the gas flow control device 114 is typically high, such as 250-400psi, and particularly 300-350psi. The first flow control device 114 may include a flow control mode in which a continuously constant total gas flow may be provided to the sample cell.

By providing the second flow rate limiting device 119 according to the present invention, the problem of uneven flow rate in each of the sample cells (for example, the first to fourth sample cells 112b to 112 e) can be effectively solved, because the second flow rate limiting device 119 can keep the flow rate of the supplied gas at a desired flow rate at a low cost. It will of course be appreciated that the desired flow rate may allow a small float, for example within 5%, preferably within 3%, or even within 1%, of the difference between the gas flows into the extraction channels. On each second supply line, the second flow restriction device 119 is preferably, but not necessarily, arranged closer to the first flow control device 114 than the switching devices 116a-116 e.

The first supply module may further include a solvent supply unit for supplying the liquid solvent. The solvent supply unit may include a solvent pump 113 for pumping liquid solvent. Typically, the solvent pump 113 is capable of pumping liquid solvent at a relatively constant flow rate, which may be preset, but may also be user-adjustable on-line. For example, the solvent pump 113 can provide a pumping flow rate of 0.5-80 ml/min. Furthermore, the first supply module may also be arranged with a switching valve 115 downstream of the solvent pump 113 to thereby be in selective fluid communication with the respective sample cell. The solvent supply line downstream of the changeover valve, viewed in the direction of flow of the solvent, also branches into four branch lines which can be brought into fluid communication with the sample cell. In addition, a pressure sensor 118 may be arranged at a suitable location of the first supply module, for example between the changeover valve 115 and the solvent pump 113.

To supply the mixture of liquid solvent and gas to the sample cell, the first supply module may further comprise a mixing device 117 for mixing the gas with the liquid solvent. In some embodiments, the mixing device 117 is configured as a fluid junction comprising separate inlets for enabling the entry of liquid solvent and gas, respectively, and an outlet for enabling the exit of the mixed mixture. In other embodiments, however, the mixing device 117 may take on other configurations, such as valves, manifolds, etc. of the fluid components. It is to be understood that the mixing device 117 of the present invention may be implemented as a mixing unit in a broad sense, for example, a mixing line into which the second supply line for supplying the gas and the solvent supply branch line for supplying the liquid solvent may be incorporated, and is not necessarily a dedicated mixing device.

The embodiment is further illustrated below in terms of the direction of fluid flow in the sample preparation system 100. A gas, in particular an inert gas, for example high-pressure nitrogen, is supplied to the first supply line 111 of the first supply module after flowing out of the gas source 152. Downstream of the gas flow control device 114, the first supply line 111 may be divided into five branch lines 111a-111e, wherein one switching device 116a-116e (e.g., a valve) may be provided on each branch line, and wherein four parallel branch lines (i.e., the second supply line) may be provided with second flow limiting devices (e.g., first through fourth gas blocks 119b-119 e), respectively.

The liquid solvent may come from a plurality of different solvent containers, and the liquid solvents in these containers may be mixed (e.g., via a mixing valve) prior to flowing into the liquid solvent supply line 112 of the first supply module. The solvent pump 113 pumps the liquid solvent (whether or not mixed) to the switching valve 115. In some embodiments, the gas flowing through the first switching device 116a provided on the first branch line (also referred to as a main gas line) 111a may be mixed with the liquid solvent that does not flow through the switching valve 115, but may also flow directly through the switching valve 115 without being mixed. For example, the gas flowing through the second to fifth switching devices 116b to 116e and the second flow rate limiting devices (e.g., the first to fourth air resistors 119b to 119 e) provided on the second to fifth branch lines (i.e., the second supply lines 111b to 111 e) may be mixed with the liquid solvent flowing through the switching valve 115 inside the mixing device 117.

When the mixture of the liquid solvent and the gas is supplied to the sample cells (for example, the first to fourth sample cells 112b to 112 e), the liquid solvent may be pumped to the switching valve 115 by the solvent pump 113 on the one hand, divided into four liquid solvent supply branch lines by the switching valve 115, and the liquid solvent flows into the mixing device 117 via the four liquid solvent supply branch lines. On the other hand, the gas also flows into the mixing device 117 via the four parallel second supply lines 111b to 111e to be mixed therein with the liquid solvent. The mixed gas-liquid mixture flows from the mixing device 117 to the first to fourth sample cells 122b to 122e via the first to fourth mixing supply lines 112a to 112d, so that the analyte in the sample is dissolved therein. Preheaters 124b-124e for heating the fluid may also be disposed before the first through fourth sample cells 122b-122 e.

With the aid of the gas supply unit, in particular the second flow-limiting device, it is possible to distribute gas evenly between the individual second supply lines and the extraction channels, so that the consistency of the extraction conditions between the individual sample cells is increased and the overall extraction time of the system is increased.

Although various embodiments of the present disclosure have been described with reference to examples of sample preparation systems incorporating gas-assisted solvent extraction techniques in the various figures, it should be understood that embodiments within the scope of the present disclosure may be applied to systems, apparatuses, and methods having similar structures and/or functions.

The foregoing description has set forth numerous features and advantages, including various alternative embodiments, as well as details of the structure and function of the devices and methods. The intent herein is to be exemplary and not exhaustive or limiting.

It will be obvious to those skilled in the art that various modifications may be made, especially in matters of structure, materials, elements, components, shape, size and arrangement of parts including combinations of these aspects within the principles described herein, as indicated by the broad, general meaning of the terms in which the appended claims are expressed. To the extent that such various modifications do not depart from the spirit and scope of the appended claims, they are intended to be included therein as well.

Claims (10)

1. A sample preparation system, comprising:

a plurality of parallel extraction channels, each extraction channel comprising a sample cell for placing a sample;

a gas supply unit for supplying gas to the respective sample cells, the gas supply unit comprising:

a first supply line;

a plurality of parallel second supply lines branching off from the first supply line, each second supply line being in fluid communication with a corresponding one of the extraction channels, the second supply lines being located between the first supply line and the extraction channels, as seen in the flow direction of the gas;

a first flow control device arranged on the first supply line to control a total flow of gas supplied to the plurality of extraction channels;

a plurality of second flow restriction devices, each disposed on a corresponding one of the second supply lines, the second flow restriction devices including a resistance providing structure configured such that a difference between gas flow rates flowing into the respective extraction channels is less than a predetermined threshold.

2. The sample preparation system of claim 1, wherein the first flow control device is configured as a mass flow controller.

3. The sample preparation system of claim 1, wherein the resistance providing structure of the second flow restriction device is configured to increase a flow resistance of gas flowing through the corresponding second supply line by a factor of 10 to 100.

4. The sample preparation system of claim 1, wherein the resistance providing structure of the second flow restriction device is configured to enable the predetermined threshold to be 5% of a flow rate of gas flowing from one second supply line into the corresponding extraction channel.

5. The sample preparation system of claim 1, wherein the resistance providing structure comprises a porous structure.

6. The sample preparation system of claim 1, wherein the resistance providing structure comprises a narrowed portion having an inner diameter that is narrowed relative to an inner diameter of the tubing of the second supply line.

7. The sample preparation system of claim 1, wherein the resistance providing structure comprises at least one bend.

8. The sample preparation system of claim 6, wherein the narrowed portion comprises a tube segment having an inner diameter of less than 0.2 mm.

9. The sample preparation system according to claim 1, wherein a switching device for controlling the switching of the gas in the second supply line is further arranged on the second supply line, and the second flow restriction device is arranged between the first flow control device and the switching device.

10. The sample preparation system of claim 1, wherein no mass flow controller is disposed between the first flow control device and the extraction channel.

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