CN105929012A - Spray chamber, sampling system and ICP-MS using spray chamber - Google Patents

Abstract

The invention provides a spray chamber used for a sampling system of an inductively coupled plasma massspectrometry (ICP-MS), the sampling system using the spray chamber, and ICP-MS using the spray chamber. The 3D printing technology is used, ABS plastic is used as the material, and the whole consumption type spray chamber used for the sampling system of ICP-MS is designed. The spray chamber is prepared by sleeving two concentric cylinders, can be used for separating and detecting silver ionic with different concentration, and can promote separation and detection used for nano-particle and other metal ionic. The sampling efficiency of the spray chamber is better than that of the common commercial two-channel cylindric spray chamber, and the spray chamber has low cost, simple manufacture process, stable signal, high throughput, and high detection sensitivity, and has possible of continuous optimization.

Description

Spray chamber, sampling system using it, and ICP-MS

technical field

The invention belongs to the technical field of chemical detection and analysis, and more particularly relates to a spray chamber used for an inductively coupled plasma mass spectrometer (ICP-MS) sampling system, a sampling system using the same and the ICP-MS.

Background technique

Inductively coupled plasma mass spectrometry is an inorganic multi-element analysis technology that uses inductively coupled plasma as the ion source and is detected by a mass spectrometer. It is mainly composed of a sample introduction system, ion source, interface part, ion focusing system, mass analyzer, and detection system. It consists of several parts. Since its inception, ICP-MS technology has been continuously improved and perfected, and has rapidly developed into a highly appraised elemental analysis technology widely used in various fields, and has achieved a large number of research results. This technology has the advantages of high sensitivity, low detection limit, many elements that can be determined, wide linear range, isotope analysis and multi-element simultaneous detection, and wide application range.

The sampling system is an important part of ICP-MS, which has a great influence on the analysis performance. There are many ways to introduce ICP-MS samples, but the most commonly used and basic one is the solution pneumatic atomization sampling system. The solution pneumatic atomization sampling system is composed of a peristaltic pump, nebulizer and spray chamber. The general requirements for the sampling system are: high atomization efficiency, reducing solvent introduction as much as possible to reduce oxides and other interferences; The length of the sample pipeline is as short as possible to reduce the memory effect; the sample injection system is external for easy operation, replacement or cleaning. Among them, the spray chamber has a great influence on the repeatability and stability of the sampling system. The main function of the spray chamber is to remove large mist particles (diameter greater than 10 μm) from the airflow and discharge them; the second is to eliminate or slow down the nebulization The pulse phenomenon mainly caused by the peristaltic pump in the process can obtain higher aerosol transmission efficiency and enable the aerosol mist particles to be rapidly desolvated, evaporated and atomized after reaching the plasma. At present, the Scott dual-channel cylindrical spray chamber is commonly used in the sampling system of ICP-MS. However, the spray transmission efficiency of this spray chamber is low, and only 1% to 2% of the aerosol can be transmitted to the plasma in the end. , and about 98% to 99% of the sample solution is discharged as waste liquid, and the dead volume of the entire spray chamber is large, which limits the detection sensitivity of the instrument.

Contents of the invention

In view of this, the object of the present invention is to provide a spray chamber for an ICP-MS sampling system.

In order to achieve the above technical purpose, as an aspect of the present invention, the present invention provides a spray chamber for ICP-MS sampling system, wherein:

The atomization chamber is divided into a front half and a second half, the front half is a cylindrical double-layer structure, the front end is provided with an atomizer installation port, and the two sides of the front end of the outer cylinder of the double-layer structure are provided with compensation The gas inlet is used to input the compensation gas into the interlayer between the outer cylinder and the inner cylinder of the double-layer structure; the inner cylinder of the double-layer structure gradually expands from the waist to the tail end, and is connected with the inner cylinder of the double-layer structure. A gap is formed between the inner walls of the outer cylinder; the main body of the second half is a conical single-layer structure, seamlessly connected with the outer cylinder of the first half, and the inner wall of the second half shrinks gradually to the atomization The rear end of the chamber forms a rear cavity of the spray chamber, and the opening of the rear end of the spray chamber rear cavity forms a hemispherical concave surface for fitting with the circular joint of the ICP-MS torch connector.

Wherein, the atomization chamber is made of high molecular polymer material.

Wherein, the atomization chamber is made of ABS plastic.

Wherein, the atomization chamber is manufactured by 3D printing technology.

Wherein, the axes of the outer cylinder and the inner cylinder of the first half of the atomization chamber are coincident.

Wherein, a gap of less than 1 mm, preferably 0.5 mm, is formed between the outer cylinder and the inner cylinder of the first half of the atomization chamber to help the compensating gas form an airflow layer inside the outer cylinder.

Wherein, the tail end of the inner cylinder of the first half of the spray chamber is shorter than the outer cylinder by 1-3 mm, preferably 1 mm.

Wherein, the atomization chamber is a total consumption type atomization chamber.

As another aspect of the present invention, the present invention also provides an ICP-MS sampling system using the above-mentioned spray chamber.

As another aspect of the present invention, the present invention also provides an inductively coupled plasma mass spectrometer using the above-mentioned ICP-MS sampling system.

Based on the above scheme, it can be seen that the atomization chamber of the present invention has the following beneficial effects: (1) the material used in the atomization chamber of the present invention is about 24 grams, and the cost is about 50 yuan, light in weight and low in cost; (2) the material of the atomization chamber of the present invention The nebulizer is inserted from the spray chamber, and the sample aerosol can directly enter the spray chamber and the torch connector along the axis to reduce the dead volume; (3) The compensation gas passes through the end of the spray chamber and the wall of the spray chamber. A thin film is formed in the gap, which can prevent the loss caused by the collision and adsorption of the sample and the wall of the atomization chamber, and eliminate the memory effect; (4) The introduction of compensation gas from both sides of the front end of the atomization chamber can make the aerosol enter the plasma more uniformly, Improve transmission efficiency; (5) The injection efficiency of the spray chamber of the present invention is better than that of common commercial double-channel cylindrical spray chambers, and has the characteristics of simple manufacturing process, stable detection signal, high throughput, and high detection sensitivity, and It is possible to continue to optimize.

Description of drawings

Fig. 1 is a schematic cross-sectional view of the structure of the atomization chamber of the present invention; in the figure: 1. atomizer, 2. compensation gas inlet, 3. outer cylinder of atomization, 4. cylinder of atomization chamber, 5. end of cylinder of atomization chamber 6. Spray chamber rear cavity, 7. Spray chamber torch connector interface;

Fig. 2 is the comparison diagram of the detection results of different spray chambers of different concentrations of silver ion standard solutions; in the figure: a. the Agilent double-channel spray chamber after tuning is to the detection results of different concentrations of silver standard solutions, b. the present invention after tuning The detection results of different concentrations of silver standard solutions in the spray chamber;

Figure 3 is a comparison chart of the detection results of different spray chambers for silver ion standard solutions with different flow rates at low concentrations (20ng L ^-1 ); Result, b. the detection results of silver standard solutions with different flow rates by the spray chamber of the present invention after tuning.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

The atomization chamber of the present invention is a full-consumption single-channel atomization chamber, which is made of polymer materials, such as ABS plastic, and has the following advantages: the concentric atomizer is inserted into the cylinder of the atomization chamber from the front end of the atomization chamber, The sample aerosol can be directly brought into the plasma by the compensation gas from the outlet at the rear end of the coaxial spray chamber, which reduces the dead volume and memory effect. A gap is formed, so that the compensation gas can adhere to the wall after entering from both sides of the front end of the atomization chamber, forming an argon film to prevent the loss of the sample's adhesion to the wall, and the compensation gas can be introduced from both sides of the front end of the spray chamber to make the aerosol enter evenly Plasma, improve transmission efficiency.

More specifically, the present invention discloses a spray chamber for ICP-MS sampling system. The front half of the spray chamber has a double-layer structure. There are compensation gas inlets on both sides of the front end of the cylinder. The outer cylinder of the spray chamber shrinks gradually to the rear end of the spray chamber to form the rear cavity of the spray chamber. The circular joint of the torch connector fits well, and the barrel inside the spray chamber gradually expands from the waist to the tail end, and forms a gap with the inner wall of the outer cylinder of the spray chamber.

As a preferred embodiment, the spray chamber for the ICP-MS sampling system is printed using a commercial 3D printer. The printing material is ABS plastic. Slightly shorter than the outer cylinder of the spray chamber.

A preferred embodiment of the present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figure 1, the spray chamber for the ICP-MS sampling system is made of ABS plastic, with a total weight of about 24 grams. The spray chamber includes: compensation gas inlet 2, spray chamber 3, Atomization chamber 4, atomization chamber rear end 5, spray chamber rear cavity 6, spray chamber torch connector interface 7, the front end of the spray chamber has a mounting port connected to the atomizer 1, spray chamber outside the cylinder 3 The tail end gradually shrinks to the end of the spray chamber to form the rear cavity 6 of the spray chamber. There is a circular spray chamber torch connector interface 7 connected to the ICP-MS torch connector at the end of the spray chamber. 4 coincides with the axis of the atomizing outer cylinder 3, the atomizing indoor cylinder 4 gradually expands from the waist to the atomizing indoor cylinder tail end 5, and the atomizing indoor cylinder tail end 5 forms a gap with the inner wall of the atomizing outer cylinder 3. The tail end 5 of the atomizing indoor cylinder is slightly shorter than the length of the atomizing external cylinder 3 .

When the atomization chamber is working, the aerosol enters the rear cavity 6 of the atomization chamber through the atomizer 1, and the compensation gas enters the atomization outer cylinder 3 from the compensation gas inlet 2, and then passes through the atomization outer cylinder 3 in the direction of the arrow The gap formed by the inner wall and the tail end 5 of the spray chamber enters the rear cavity 6 of the spray chamber, and carries the sample aerosol along the direction of the arrow through the torch connector interface 7 of the spray chamber and enters the torch.

Example 1

Taking a series of silver standard solutions with different concentrations as an example, the standard dual-channel spray chamber of Agilent 8800 and this spray chamber were used to detect them, and the detection sensitivity was compared.

The concentrations of the prepared silver standard solutions are 0, 1, 2, 5, 10, 20, 50ng mL ^-1 . The instrument used was Agilent 8800ICP/MS/MS inductively coupled plasma mass spectrometer, and the sampling device was the lift pump that comes with the instrument itself, and the injection volume was 1mL min ^-1 . Use the Agilent 8800 standard dual-channel spray chamber, tune the ICP-MS to the best state, and then measure the series of silver standard solutions; then use the spray chamber of the present invention to tune the instrument, and measure the series under the optimal measurement conditions after tuning. Silver standard solution. The measurement results are shown in Figure 2, in the figure a is the result of measurement using the Agilent 8800 standard dual-channel spray chamber after tuning; b is the measurement result after tuning and optimization of the spray chamber of the present invention, as can be seen from the figure , the detection efficiency of the atomization chamber of the present invention after tuning is about doubled compared with the detection efficiency of the tuned commercial double-channel spray chamber.

Example 2

Under the conditions of low concentration (20ng L ^-1 ) and different low flow rates (injection volume 0-100μl/min), using the dual-channel spray chamber of Agilent 8800 and the spray chamber of the present invention were used to analyze the series of silver particles with different concentrations. The standard solution was tested, and the detection sensitivity was compared.

The prepared silver standard solution has a concentration of 20ng L ^-1 . The instrument used was an Agilent 8800ICP/MS/MS inductively coupled plasma mass spectrometer, the sampling device was an external syringe pump and a 250 μL injection needle, and a capillary with a diameter of 75 μm was used for sampling. The injection volumes were controlled to be 5, 10, 20, 50, and 100 μL min ^-1 by adjusting the syringe pump. First use the dual-channel spray chamber of Agilent 8800 standard configuration, tune the ICP-MS to the best state, and measure the silver standard solutions of different injection volumes; then use the spray chamber of the present invention, under the optimal measurement conditions after tuning Determination of silver standard solutions with different injection volumes. The measurement results are shown in Figure 3, in the figure a is the result of measurement using Agilent 8800 standard dual-channel spray chamber after tuning; b is the measurement result after tuning and optimization of the spray chamber of the present invention, as can be seen from the figure , in the case that the device itself is not optimized, under the condition of low concentration and low flow rate, the test results of the spray chamber of the present invention are roughly equivalent to those of the commercial dual-channel spray chamber.

Through such a design, the present invention discloses a new type of total consumption spray chamber, which can be used in the ICP-MS sampling system. With this spray chamber, the sample aerosol can enter the spray chamber and the torch connector along a straight line. Reduce the dead volume; when the compensation gas passes through the gap between the end of the atomization chamber and the inner wall of the spray chamber, a thin film will be formed, which can prevent the sample from colliding with the spray chamber and loss caused by adsorption, and eliminate the memory effect; from both sides of the bottom of the spray chamber The introduction of compensation gas can make the aerosol enter the plasma more uniformly and improve the transmission efficiency; and, the superior detection performance at low concentration and low flow rate makes the spray chamber more suitable for modern analysis and detection, and may be applied In the combination of high-sensitivity instruments such as UPLC and ICP-MS.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. Within the spirit and principles of the present invention, any modifications, equivalent replacements, improvements, etc., shall be included in the protection scope of the present invention.

Claims (10)

1. the spray chamber for ICP-MS sampling system, it is characterised in that:

Described spray chamber is divided into first half and latter half, described first half to be cylindrical double knot Structure, front end is provided with atomizer installing port, and both sides, described double-deck outer cylinder front end are provided with compensation Gas air inlet, for inputting compensating gas between described double-deck outer cylinder and inner cylinder In interlayer；Described double-deck inner cylinder gradually expands from waist to tail end, and with described outside Gap is formed between cylinder inner wall；Described latter half main body is cone single layer structure, before described The outer cylinder seamless link of half part, the inwall of described latter half gradually tapers up to described spray chamber Rear end formed spray chamber back cavity, described spray chamber back cavity tail end opening formed hemispherical concave surface, for The circular joint of ICP-MS torch pipe connector agrees with.

Spray chamber for ICP-MS sampling system the most according to claim 1, its feature exists In, described spray chamber uses macromolecule polymer material to make.

Spray chamber for ICP-MS sampling system the most according to claim 2, its feature exists In, described spray chamber uses ABS plastic to make.

Spray chamber for ICP-MS sampling system the most according to claim 1, its feature exists In, described spray chamber is manufactured by 3D printing technique.

Spray chamber for ICP-MS sampling system the most according to claim 1, its feature exists In, the outer cylinder of described spray chamber first half and the dead in line of inner cylinder.

Spray chamber for ICP-MS sampling system the most according to claim 1, its feature exists In, formed between outer cylinder and the inner cylinder of described spray chamber first half less than between 1mm Gap, preferably 0.5mm gap, it is internally formed airflow layer at urceolus helping compensate for gas.

Spray chamber for ICP-MS sampling system the most according to claim 1, its feature exists In, the inner cylinder tail end 1-3mm shorter than described outer cylinder of described spray chamber first half, preferably 1mm。

Spray chamber for ICP-MS sampling system the most according to claim 1, its feature exists In, described spray chamber is full consumption type spray chamber.

9. the ICP-MS sample introduction of the spray chamber used as described in claim 1 to 8 any one System.

10. the inductive etc. using ICP-MS sampling system as claimed in claim 9 from Daughter mass spectrograph.