Abstract:
The present invention discloses an integrated analysis device for simultaneously detecting exhaled breath condensates (EBCs) and volatile organic compounds (VOCs) in human exhaled breath. The device comprises a module for sampling, separating and enriching a detected object, an EBCs detection module and a combined VOCs detection module. The module for sampling, separating and enriching a detected object is connected with the EBCs detection module via a syringe pump for sample injection. The module for sampling, separating and enriching a detected object is connected with the combined VOCs detection module by a capillary separation column. In the present invention, it is achieved that EBCs and VOCs in human exhaled breath are simultaneously sampled, separated and condensed; the heavy metal ions, cell factors, etc. in the collected EBCs are detected with a light addressable potentiometric sensor (LAPS); the condensed VOCs can be quantitatively detected by the combined VOCs detection module with a high sensitivity; and a heating rod and a platinum resistor can be conveniently replaced because a separated outlet heating piece is designed in the combined VOCs detection module.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to an integrated analysis device for simultaneously detecting human exhaled breath condensates (EBCs) and volatile organic compounds (VOCs) in exhaled breath, and in particular, to an integrated analysis device in which a light addressable potentiometric sensor (LAPS) is employed to detect EBCs, a simultaneous sampling, separation and condensation of EBCs and VOCs from human exhaled breath can be achieved, and a VOC detection module with an combined structure is employed. 
       BACKGROUND OF THE INVENTION 
       [0002]    Recently, human exhaled breath has been widely studied around the world, and these words primarily focus on the relevance of EBCs and VOCs in exhaled breath to human diseases. 
         [0003]    To study EBCs and VOCs in exhaled breath, the first step is to collect these two study objects. With regard to a device for collecting EBCs, there are relevant studies around the world, and there already have been some commercialized instruments and devices, which principles rely on that exhaled breath is first passed through a condensation tube, and then the liquid EBCs are collected. Therein, for some devices the cost of detection is increased due to the condensation tube being disposable, and for some other devices the flexibility in application is insufficient due to their large-sized cooler. 
         [0004]    Currently, there is no unified standard for the device for collecting VOCs in human exhaled breath, however, there already have been some relevant studies. In a VOCs gas collecting device developed by Michael Phillips, USA, exhaled breath is first blew into one end of a gas container by a disposable mouthpiece, wherein the other end of the gas container is connected to an adsorption tube, the gases in the container are drawn out by the adsorption tube through the other end of the pump, and thus the VOCs in the exhaled breath are captured by the adsorption tube. This device is comparatively automated, however, it takes into account neither the adsorption of the VOCs by the container and other connecting pieces, nor the adsorption temperature of the adsorption tube in every sampling process. 
         [0005]    Furthermore, nowadays internationally the existing devices can only collect either EBCs or VOCs, and internationally there is a lack of device which can collect EBCs and VOCs simultaneously, and there is also no report about the studies of integrating two sets of collecting methods into one instrument and performing a subsequent analysis and detection. 
         [0006]    To obtain EBCs, exhaled breath is introduced into a cooling system, and water vapor is condensed into liquid by means of a low temperature. EBCs contain water vapor, adenosine, hydrogen peroxide, ions, nitric oxide, prostaglandins, protein and nucleic acid, etc. which are brought out from the lung and the respiratory tract. With the features of simple to collect, non-invasive, acceptable to patients, etc., EBCs may become a new approach for finding the early diagnosis of lung cancer, screening of high-risk groups, etc. However, current common detection means are general immunological methods of which the detection speed is low, the process is complex, and the sensitivity is not high. 
         [0007]    A surface acoustic wave (SAW) gas sensor has been widely applied in gas detection. However, since its characteristics are influenced by many environmental factors (such as gas flow, temperature, etc.) and the area of its sensitive region is relatively small so that it is difficult for chemical substances to be fully adsorbed to the sensor surface, its characteristic of high sensitivity cannot be completely achieved. If the working environmental conditions of the SAW gas sensor are not strictly controlled, the goal of rapidly detecting chemical substances with low trace concentrations in human exhaled breath cannot be achieved. A heating rod and a platinum resistor directly inserted in the traditional outlet heating piece of capillary will expand by heat after use, and get stuck in the heating piece, which makes it difficult to replace them. 
       SUMMARY OF THE INVENTION 
       [0008]    An object of the present invention is to provide an integrated analysis device for simultaneously detecting EBCs and VOCs in human exhaled breath considering the deficiencies of the internationally existing research methods and devices. 
         [0009]    The object of the present invention is achieved by the following solution: an integrated analysis device for simultaneously detecting EBCs and VOCs in human exhaled breath comprises a module for sampling, separating and enriching a detected object, an EBCs detection module and a combined VOCs detection module; the module for sampling, separating and enriching a detected object is connected with the EBCs detection module via a syringe pump for sample injection, and the module for sampling, separating and enriching a detected object is connected with the combined VOCs detection module via a capillary separation column. Therein, the EBCs detection module comprises an EBC inlet, an inlet for washing liquid, a first three-way valve, a composite LAPS sensor for heavy metal ions, a first working electrode, a light source controlled by a signal generating circuit, a reference electrode, a second three-way valve, a urea inlet, a detecting electrode, a CEA-LAPS sensor, a second working electrode, a Cr 3+  ion detecting cavity and a CEA detecting cavity; the EBC inlet, the inlet for washing liquid and the Cr 3+  ion detecting cavity are connected via the first three-way valve, the urea inlet, the Cr 3+  ion detecting cavity and the CEA detecting cavity are connected via the second three-way valve, the reference electrode is inserted into the Cr 3+  ion detecting cavity from its top, the composite LAPS sensor for heavy metal ions and the first working electrode are fixed to the bottom of the Cr 3+  ion detecting cavity, the first working electrode is joined with the bottom of the composite LAPS sensor for heavy metal ions, the detecting electrode is inserted into the CEA detecting cavity from its top, the CEA-LAPS sensor and the second working electrode are fixed to the bottom of the CEA detecting cavity, and the second working electrode is joined with the bottom of the CEA-LAPS sensor. An inlet for CEA antibody-urease compound liquid and an outlet for waste liquid are disposed at the upper portion of the CEA detecting cavity. One light source controlled by a signal generating circuit is placed at a position corresponding to the composite LAPS sensor for heavy metal ions under the Cr 3+  ion detecting cavity, and another light source controlled by a signal generating circuit is placed at a position corresponding to the CEA-LAPS sensor under the CEA detecting cavity. 
         [0010]    Furthermore, the CEA-LAPS sensor is built by depositing a SiO 2  layer and a Si 3 N 4  film in turn on a Si substrate by the chemical vapor deposition and the photolithography, and a nanolayer and a biotin layer on the surface of the Si 3 N 4  film are formed by a chemical coating method. 
         [0011]    Compared to the prior art, the present invention has the following technical effects: 
         [0012]    1. In the method and the integrated analysis device for simultaneously detecting EBCs and VOCs in human exhaled breath provided by the present invention, it is achieved that EBCs and VOCs in human exhaled breath are simultaneously sampled, separated and enriched; substances in the collected EBCs (such as heavy metal ions, cell factors, etc.) are detected with the LAPS; and the enriched VOCs can be quantitatively detected via the combined VOCs detection module with a high sensitivity. 
         [0013]    2. The EBCs detection module includes two test cavities and two LAPS sensors which perform a simultaneous detection of Cr 3+  and CEA in EBCs. In the first test cavity, one LAPS sensor with surface modification by heavy metal ion (e.g. Cr 3+ ) sensitive materials performs the detection of Cr 3+ ; in the second test cavity, the other LAPS immune sensor successively modified by nanometer material, biotin-avidin and CEA antibody, in which the CEA antibody, the target antigen CEA, and the added CEA antibody-urease compound form a dual antibody sandwich structure and altering the concentration of H +  by decomposing urea by the urease, thereby realizing the detection of the CEA concentration. At the back of the two LAPS sensors two light sources with different frequencies are employed to excite the sensor cells of Cr 3+  and CEA respectively, thereby realizing a simultaneous detection of Cr 3+  and CEA in exhaled breath condensates with two sensors of the same detection module. 
         [0014]    3. In the module for sampling, separating and enriching a detected object integrates a gas path construction for collecting the EBCs and enriching the VOCs in exhaled breath, and the automated sampling and injection are achieved for the subsequent detection; this method utilizes an innovative cooling measure so as to realize the automated collecting and cleaning while guaranteeing the efficiency of collecting the exhaled breath condensates, and to effectively reduce the weight and volume of the condensation system; and this method ensures that less exhaled breath is left over in the pipeline, and the breath from anatomical dead space in medicine is effectively removed during the enrichment of VOCs. 
         [0015]    4. The VOCs detection module employs a combined gas detection head structure, in which a snap-fit gas chamber makes the capillary outlet aim to the sensitive region of the gas sensor accurately, thereby ensuring that the VOCs in the sample are efficiently adsorbed by the gas sensor. The design of the gas chamber leads the sensor to work in a relatively closed room, which decreases the influence of the environmental gas flow on the gas sensor, and an observation window is disposed around the gas chamber so that the working condition of the sensor is observed. Below the sensor, there is a semiconductor cooling plate which can accurately control the working temperature of the sensor, and reduce the influence of the temperature characteristics of the sensor on the detection of VOCs. The design of a separated outlet heating piece in the detection head may facilitate the replacement of heating rod and platinum resistor. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a system structure block diagram of an integrated device for detecting EBCs and VOCs in human exhaled breath; 
           [0017]      FIG. 2  is a working process in which a module for sampling, separating and enriching a detected object collects a particular portion of the exhaled breath; 
           [0018]      FIG. 3  is a working process in which a module for sampling, separating and enriching a detected object collects EBCs and enriches VOCs from the exhaled breath; 
           [0019]      FIG. 4  is a structural cross-section view of a gas buffering chamber in a module for sampling, separating and enriching a detected object; 
           [0020]      FIG. 5  is a structural cross-section view of a VOCs enriching device in a module for sampling, separating and enriching a detected object; 
           [0021]      FIG. 6  is a structural cross-section view of a condensation module in a module for sampling, separating and enriching a detected object; 
           [0022]      FIG. 7  is a structural schematic diagram of a combined VOCs detection module; 
           [0023]      FIG. 8  is a structural schematic diagram of a separated outlet heating piece; 
           [0024]      FIG. 9  is a structural schematic diagram of a snap-fit gas chamber; 
           [0025]      FIG. 10  is a structural schematic diagram of an EBCs detection module; 
           [0026]      FIG. 11  is a structural schematic diagram of a CEA detecting cavity. 
       
    
    
       [0027]    In the drawings: 
         [0028]      1  disposable mouthpiece 
         [0029]      2  saliva collector 
         [0030]      3  inspiration check valve 
         [0031]      4  expiration check valve 
         [0032]      5  first three-way solenoid valve 
         [0033]      6  second three-way solenoid valve 
         [0034]      7  activated carbon filter 
         [0035]      8  inlet check valve 
         [0036]      9  gas buffering chamber 
         [0037]      10  third three-way solenoid valve 
         [0038]      11  gas outlet 
         [0039]      12  adsorption tube 
         [0040]      13  miniature vacuum pump 
         [0041]      14  gas mass flow meter 
         [0042]      15  linear stepping motor 
         [0043]      16  piston 
         [0044]      17  washing liquid storage for condensation tube 
         [0045]      18  peristaltic pump 
         [0046]      19  condensation module 
         [0047]      20  condensate collector 
         [0048]      21  heating rod 
         [0049]      22  heating piece 
         [0050]      23  conduit 
         [0051]      24  aluminium piece 
         [0052]      25  cooling plate 
         [0053]      26  gas inlet 
         [0054]      27  inlet for washing liquid 
         [0055]      28  condensation tube 
         [0056]      29  ice cooling box 
         [0057]      30  condensate outlet 
         [0058]      31  outlet heating piece 
         [0059]      32  gas nozzle 
         [0060]      33  upper cover of sensor gas-chamber 
         [0061]      34  heat sink 
         [0062]      35  conduit for capillary extraction 
         [0063]      36  first perforation for hanging and fixing 
         [0064]      37  first screw perforation for heating piece incorporating 
         [0065]      38  second screw perforation for heating piece incorporating 
         [0066]      39  first pin perforation for heating piece 
         [0067]      40  second pin perforation for heating piece 
         [0068]      41  cambered guiding groove for capillary 
         [0069]      42  third pin perforation for heating piece 
         [0070]      43  second perforation for hanging and fixing 
         [0071]      44  fourth pin perforation for heating piece 
         [0072]      45  slot for heating rod 
         [0073]      46  slot for platinum resistor 
         [0074]      47  first insertion screw hole 
         [0075]      48  second insertion screw hole 
         [0076]      49  gas chamber fixing hole 
         [0077]      50  gas chamber top hole 
         [0078]      51  first gas chamber closing hole 
         [0079]      52  observation hole 
         [0080]      53  groove for cooling plate 
         [0081]      54  groove for the lead wire of cooling plate 
         [0082]      55  gas chamber embedding groove 
         [0083]      56  second gas chamber closing hole 
         [0084]      57  EBC inlet 
         [0085]      58  inlet for washing liquid 
         [0086]      59  first three-way valve 
         [0087]      60  composite LAPS sensor for heavy metal ions 
         [0088]      61  first working electrode 
         [0089]      62  light source controlled by a signal generating circuit 
         [0090]      63  reference electrode 
         [0091]      64  second three-way valve 
         [0092]      65  urea inlet 
         [0093]      66  inlet for CEA antibody-urease compounds 
         [0094]      67  detecting electrode 
         [0095]      68  CEA-LAPS sensor 
         [0096]      69  second working electrode 
         [0097]      70  outlet for waste liquid 
         [0098]      71  bias voltage 
         [0099]      72  Si substrate 
         [0100]      73  SiO 2  layer 
         [0101]      74  Si 3 N 4  layer 
         [0102]      75  nanolayer 
         [0103]      76  biotin layer 
         [0104]      77  CEA antigen 
         [0105]      78  CEA antibody-urease 
         [0106]      79  CEA antibody-avidin. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0107]    In the following the present invention will be further described in connection with the drawings and embodiments, and the objects and effects of the present invention will become more apparent. 
         [0108]    As shown in  FIG. 1 , an integrated analysis device for simultaneously detecting EBCs and VOCs in human exhaled breath of the present invention comprises a module for sampling, separating and enriching a detected object, an EBCs detection module and a combined VOCs detection module. Therein, the module for sampling, separating and enriching a detected object is connected with the EBCs detection module via a syringe pump for sample injection, and the module for sampling, separating and enriching a detected object is connected with the combined VOCs detection module via a capillary separation column. 
         [0109]    Exhaled breath sample is blown into the module for sampling, separating and enriching a detected object by a person, and after the saliva is filtered, the EBCs are collected and the VOCs are enriched in two sets of pipelines. The collected EBCs come into the EBCs detection module via the syringe pump for sample injection, and the concentrations of Cr 3+  ions and CEA in the EBCs are directly measured. The enriched VOCs are separated in the capillary separation column, and passed into the combined VOCs detection module with a gas sensor whose working conditions are strictly controlled, thereby realizing a detection with a high sensitivity. 
         [0110]    As shown in  FIGS. 2 and 3 , the module for sampling, separating and enriching a detected object comprises a mouthpiece  1 , a saliva collector  2 , an inspiration check valve  3 , an expiration check valve  4 , a first three-way solenoid valve  5 , a second three-way solenoid valve  6 , an activated carbon filter  7 , an inlet check valve  8 , a gas buffering chamber  9 , a third three-way solenoid valve  10 , a gas outlet  11 , an adsorption tube  12 , a miniature vacuum pump  13 , a gas mass flow meter  14 , a linear stepping motor  15 , a piston  16 , a washing liquid storage for condensation tube  17 , a peristaltic pump  18 , a condensation module  19 , and a condensate collector  20 . 
         [0111]    Therein, the mouthpiece  1  is connected with the first three-way solenoid valve  5  via the inspiration check valve  3  and the expiration check valve  4  in turn, the saliva collector  2  is connected between the mouthpiece  1  and the inspiration check valve  3 , the two outlets of the first three-way solenoid valve  5  are connected respectively with the second three-way solenoid valve  6  and the gas mass flow meter  14 , the inlet check valve  8  is then connected with the third three-way solenoid valve  10  via the activated carbon filter  7 , the second three-way solenoid valve  6  and the gas buffering chamber  9  in turn, the two outlets of the third three-way solenoid valve  10  are then connected respectively with the gas outlet  11  and with the adsorption tube  12  to the miniature vacuum pump  13 , the gas mass flow meter  14  is connected with the condensation module  19 , and all the above connections are gas pipeline connections. The washing liquid storage for condensation tube  17  is connected with the condensate collector  20  in a liquid pipeline via the peristaltic pump  18  and the condensation module  19  in turn. The linear stepping motor  15  is connected with the piston  16 , and drives the piston  16  into the condensation module  19 . 
         [0112]      FIG. 2  shows a working process in which the module for sampling, separating and enriching a detected object collects a particular portion of the exhaled breath. 
         [0113]    The components of the module for sampling, separating and enriching a detected object involved in the working process comprise the disposable mouthpiece  1 , the saliva collector  2 , the inspiration check valve  3 , the expiration check valve  4 , the first three-way solenoid valve  5 , the second three-way solenoid valve  6 , the activated carbon filter  7 , the inlet check valve  8 , the gas buffering chamber  9 , the third three-way solenoid valve  10 , the gas outlet  11 , the adsorption tube  12 , and the miniature vacuum pump  13 . The expiration check valve  4  is connected to the second three-way solenoid valve  6  via the first three-way solenoid valve  5 , the first three-way solenoid valve  5  is connected to the gas buffering chamber  9  via the second three-way solenoid valve  6 , and the gas buffering chamber  9  is connected to the gas outlet  11  via the third three-way solenoid valve  10 . The gas buffering chamber  9  will be heated to 100˜150° C. by a heating rod (as shown in  FIG. 4 ) if needed, and at the same time, the cooling plates on both sides of the VOCs adsorption tube  12  (as shown in  FIG. 5 ) makes the adsorption tube  12  to a constant temperature of 20° C., thereby ensuring that the adsorption material has a comparatively large breakthrough volume value for the VOCs at the current temperature; when the temperature inside the gas buffering chamber  9  reaches a set value, the subject takes a deep breath, exhales towards the collecting device through the disposable mouthpiece  1 , and at this point the exhaled breath will pass through the following pathways: the disposable mouthpiece  1 →the expiration check valve  4 →the first three-way solenoid valve  5 →the second three-way solenoid valve  6 →the gas buffering chamber  9 →the third three-way solenoid valve  10 →the gas outlet  11 , and the gas buffering chamber  9  will keep the last 350 mL gas in the exhaled breath within its elongated stainless conduit  23 . 
         [0114]      FIG. 3  shows a working process in which the module for sampling, separating and enriching a detected object collects EBCs and enriches VOCs from the exhaled breath. 
         [0115]    The components of the module for sampling, separating and enriching a detected object involved in the working process comprise the disposable mouthpiece  1 , the saliva collector  2 , the inspiration check valve  3 , the expiration check valve  4 , the first three-way solenoid valve  5 , the second three-way solenoid valve  6 , the activated carbon filter  7 , the inlet check valve  8 , the gas buffering chamber  9 , the third three-way solenoid valve  10 , the gas outlet  11 , the adsorption tube  12 , the miniature vacuum pump  13 , the gas mass flow meter  14 , the linear stepping motor  15 , the piston  16 , the washing liquid storage for condensation tube  17 , the peristaltic pump  18 , the condensation module  19 , and the condensate collector  20 . The expiration check valve  4  is connected with the gas mass flow meter  14  via the first three-way solenoid valve  5 , the activated carbon filter  7  is connected with the gas buffering chamber  9  via the second three-way solenoid valve  6 , and the gas buffering chamber  9  is communicated with the adsorption tube  12  via the third three-way solenoid valve  10 . When the temperature of the adsorption tube  12  decreases to a set value, the miniature vacuum pump  13  start to work a set pumping speed, at this point a carrier gas (clean air) will pass through the following pathway: the inlet check valve  8 →the activated carbon filter  7 →the second three-way solenoid valve  6 →the gas buffering chamber  9 →the third three-way solenoid valve  10 →the adsorption tube  12 →the miniature vacuum pump  13 , and in this way the 350 mL exhaled breath kept within the gas buffering chamber  9  will pass through the enriching material of the adsorption tube  12  gradually along with the carrier gas, and be adsorbed by the adsorption material and condensed under a condition of a lower temperature. So, the adsorption tube  12  enriches the VOCs gas molecules from the subject exhaled breath with the anatomical dead space removed. The adsorption tube  12  is then placed in an environment of 200° C., to cause the VOCs molecules to be desorbed from the enriching material and enter the subsequent separating and detection module. 
         [0116]    Synchronously with the enrichment of the VOCs, the subject exhales more breath, and at this point the exhaled breath pass through the following pathway: the disposable mouthpiece  1 →the expiration check valve  4 →the first three-way solenoid valve  5 →the gas mass flow meter  14 →the condensation module  19 . A microcontroller will first read a temperature value from an ice cooling box  29  (as shown in  FIG. 6 ) coating a condensation tube  28  at the periphery, wherein in order to guarantee the efficiency and repeatability of the operation of the system sampling condensate samples, the condensation temperature is usually suggested to be −5° C.˜−10° C. Then, the microcontroller will read a flow value from the gas mass flow meter  14  and obtain the overall volume of the gas exhaled into the condensation tube. When reaching the required set overall volume of the exhaled gas, the linear stepping motor  15  will start to work and drive the piston  16 , to make droplets agglutinated on the wall of the condensation tube to enter the condensate collector  20  for sampling and analysis by a subsequent detection module. After the agglutination and collection of one sample is finished, the peristaltic pump  18  starts to work and pumps the washing liquid into the condensation tube  28 , and after a back and forth sliding of the piston  16 , the cleaning work is done. 
         [0117]    The above two steps are performed alternately to increase the collection efficiency of the exhaled breath collecting instrument. 
         [0118]    As shown in  FIG. 4 , the gas buffering chamber  9  comprises a heating rod  21 , a heating piece  22  and a conduit  23 , in which both the heating rod  21  and the conduit  23  are placed within the heating piece  22 . The working principle of the gas buffering chamber  9  is as follows. In operation, the heating rod  21  propagates heat to the whole heating piece  22  made of aluminium, ensuring that the temperature of the conduit  23  made of stainless steel located in the heating piece  22  is at 100° C.˜150° C., thereby reducing the condensation loss of the 350 mL exhaled breath buffered in the conduit  23  on the inner wall. 
         [0119]    As shown in  FIG. 5 , the module for sampling, separating and enriching a detected object also comprises an aluminium piece  24  and a cooling plate  25  to aid the adsorption tube  12  to finish enrichment of VOCs. The aluminium piece  24  is in close contact with the periphery of the adsorption tube  12 , and the semiconductor cooling plate  25  is fixed on the outside of the aluminium piece  24 . The working principle of this part is as follows. At the beginning of the VOCs enrichment, the semiconductor cooling plate  25  controls the temperature of the aluminium piece  24  to be maintained at 20° C., such that the temperature of the adsorption tube  12  is also maintained at 20° C., the adsorption quantity of the VOCs in the exhaled breath by the adsorption tube  12  is increased, and the repeatability of the enrichment of the adsorption tube  12  is also guaranteed. 
         [0120]    As shown in  FIG. 6 , the condensation module  19  comprises the piston  16 , the gas inlet  26 , the inlet for washing liquid  27 , the condensation tube  28 , the ice cooling box  29 , and the condensate outlet  30 . The gas inlet  26 , the inlet for washing liquid  27 , the condensate outlet  30  and the condensation tube  28  are formed integrally, the piston  16  is inserted into the condensation tube  28 , and the ice cooling box  29  is in close contact with the outside of the condensation tube  28 . The working principle of the condensation module  19  is as follows. At the beginning of the EBCs collection, the temperature of the condensation tube  28  decreases to −5° C.˜−10° C. by the ice crystals in the ice cooling box  29 ; the exhaled breath is passed into the condensation tube  28  via the gas inlet  26 , condensed, and forms small droplets on the wall of the tube; the piston  16  slides 3-5 times back and forth along the tube wall of the condensation tube  28  under the drive of an outer push rod, and the tiny droplets previously condensed on the tube wall gather into larger droplets at the condensate outlet  30 , and then will be collected by the condensate collector  20  in  FIG. 3 . Each time when the EBCs collection is finished, washing liquid for the condensation tube will come into the condensation tube  28  via the inlet for washing liquid  27 , and the piston  16  will slide back and forth again, so the residues remaining on the tube wall of the condensation tube  28  will be cleaned, thereby preparing for the EBCs collection next time. 
         [0121]    As shown in  FIG. 7 , the combined VOCs detection module comprises an outlet heating piece  31 , a gas nozzle  32 , an upper cover of sensor gas-chamber  33 , a heat sink  34 , and a conduit for capillary extraction  35 . The gas nozzle  32  and the conduit for capillary extraction  35  are respectively in a direct threaded connection with the outlet heating piece  31 , the upper cover of sensor gas-chamber  33  is snap-fitted with the heat sink  34 , the upper cover of sensor gas-chamber  33  is connected with the outlet heating piece  31 , and the gas nozzle  32  extends into the upper cover of sensor gas-chamber  33 . 
         [0122]    The capillary separation column is led out by the conduit for capillary extraction  35  and connected to the outlet heating piece  31  to ensure that the VOCs in the capillaries are kept in a high temperature state, the upper cover of sensor gas-chamber  33  is fixed with the outlet heating piece  31  via the gas chamber fixing hole  49 , and the upper cover of sensor gas-chamber  33  and the heat sink  34  are connected via the first gas chamber closing hole  51  and the second gas chamber closing hole  56  and constitute a closed gas chamber, thereby ensuring that the sensor works in a condition with a steady gas flow. The capillary separation column protrudes out from a cambered guiding groove for capillary  41  in the outlet heating piece  31  into the gas nozzle  32 , and is accurately aligned by the fixation of the relative position between the gas nozzle  32  and the sensor in the gas chamber. 
         [0123]      FIG. 8  shows the structure of the outlet heating piece  31 , which employs a separated structure, and comprises a first perforation for hanging and fixing  36 , a first screw perforation for heating piece incorporating  37 , a second screw perforation for heating piece incorporating  38 , a first pin perforation for heating piece  39 , a second pin perforation for heating piece  40 , the cambered guiding groove for capillary  41 , a third pin perforation for heating piece  42 , a second perforation for hanging and fixing  43 , a fourth pin perforation for heating piece  44 , a slot for heating rod  45 , a slot for platinum resistor  46 , a first insertion screw hole  47 , and a second insertion screw hole  48 . The separated outlet heating piece is formed by fitting two identical structures, and one of them is shown in  FIG. 8 . The relative position of the two heating pieces is fixed by adding pins into the four heating piece pin perforations  39 ,  40 ,  42 ,  44 , and then the two heating pieces are combined as a whole by screwing screws into the heating piece incorporating screw perforations  37 ,  38 . Two perforations for hanging and fixing  36 ,  43  fix the position of the outlet heating piece in the instrument. Two insertion screw holes  47 ,  48  connect the heating piece, the conduit for capillary extraction  35  and the gas nozzle  32 . The cambered guiding groove for capillary  41  leads the capillary separation column to the gas nozzle  32  from the vertical direction. 
         [0124]    A heating rod and a platinum resistor are inserted into the slot for heating rod  45  and the slot for platinum resistor  46  respectively, thereby realizing the measurement and control of the outlet temperature. When the heating rod and the platinum resistor need to be replaced, they can be conveniently taken out from their respective slots after separating the two heating pieces, if they have expanded and been clamped. 
         [0125]    As shown in  FIG. 9 , the gas chamber which consists of the upper cover of sensor gas-chamber  33  and the heat sink  34  comprises the gas chamber fixing holes  49 , a gas chamber top hole  50 , the first gas chamber closing hole  51 , observation holes  52 , a groove for cooling plate  53 , groove for the lead wire of cooling plates  54 , gas chamber embedding grooves  55 , and the second gas chamber closing holes  56 . The four centrosymmetric gas chamber fixing holes  49  fix the relative position of the upper cover of sensor gas-chamber  33  and the outlet heating piece  31 , the upper cover of sensor gas-chamber  33  is snapped into the gas chamber embedding groove  55 , the fixation of the gas chamber and the heat sink  34  is achieved via the gas chamber closing holes  51 ,  56 , and the gas nozzle  32  enters the gas chamber via the outlet of the gas nozzle, and makes the capillary separation column aim to the sensitive region of the sensor. 
         [0126]    A semiconductor cooling plate is placed in the groove for cooling plate  53  to control the working temperature of the sensor, and a wire leads out from the groove for the lead wire of cooling plate  54  to an external circuit. The heat generated when the cooling plate controls the temperature is conducted to the external environment through the heat sink  34 . The observation holes  52  are disposed around the gas chamber so that the working state of the sensor and circuit can be observed. The frequency signal generated by the sensor is led via a signal interface to an external frequency count circuit for measurement. 
         [0127]    The structure of the EBCs detection module is as shown in  FIG. 10 , comprising an EBC inlet  57 , an inlet for washing liquid  58 , a first three-way valve  59 , a composite LAPS sensor for heavy metal ions  60 , a first working electrode  61 , a light source controlled by a signal generating circuit  62 , a reference electrode  63 , a second three-way valve  64 , a urea inlet  65 , an inlet for CEA antibody-urease compounds  66 , a detecting electrode  67 , a CEA-LAPS sensor  68 , a second working electrode  69 , an outlet for waste liquid  70 , a Cr 3+  ion detecting cavity and a CEA detecting cavity. 
         [0128]    Therein, the EBC inlet  57 , the inlet for washing liquid  58  and the Cr 3+  ion detecting cavity are connected via the first three-way valve  59 , the urea inlet  65 , the Cr 3+  ion detecting cavity and the CEA detecting cavity are connected via the second three-way valve  64 , the reference electrode  63  is inserted into the Cr 3+  ion detecting cavity from its top, the composite LAPS sensor for heavy metal ions  60  and the first working electrode  61  are fixed to the bottom of the Cr 3+  ion detecting cavity, the first working electrode  61  is joined with the bottom of the composite LAPS sensor for heavy metal ions  60 , the detecting electrode  67  is inserted into the CEA detecting cavity from its top, the CEA-LAPS sensor  68  and the second working electrode  69  are fixed to the bottom of the CEA detecting cavity, and the second working electrode  69  is joined with the bottom of the CEA-LAPS sensor  68 . At the upper portion of the CEA detecting cavity are disposed the inlet for CEA antibody-urease compound liquid  66  and the outlet for waste liquid  70 . One light source controlled by a signal generating circuit  62  is placed at a position corresponding to the composite LAPS sensor for heavy metal ions  60  under the Cr 3+  ion detecting cavity, and another light source controlled by a signal generating circuit  62  is placed at a position corresponding to the CEA-LAPS sensor  68  under the CEA detecting cavity. 
         [0129]    A particular working process is as follows. The surface of the composite LAPS sensor for heavy metal ions  60  is prepared by employing the pulse laser deposition (PLD) and the material sensitive to heavy metal ions (Cr 3+ ) is made; the CEA-LAPS sensor is prepared by employing the chemical vapor deposition (CVD) and the material sensitive to H +  is made, then the further immunologically modification could be carried out. 
         [0130]    The human exhaled breath condensate is passed into the EBC detection module via the EBC inlet  57 , and at the same time the composite LAPS sensor for heavy metal ions  60  starts to work and obtains the content of Cr 3+  ions in the condensate by detection. Then, the second three-way valve  64  is opened and the condensate is passed into the CEA detecting cavity. At this point, the CEA antibody-urease  78  compounds inflow via the inlet for CEA antibody-urease compound  66 , are bonded with the CEA antigen  77  in the condensate, and form a sandwich structure with the CEA antibody-avidin  79 , which is affixed to the CEA-LAPS sensor  68 . Then, the washing liquid is passed into the cavity via the inlet for washing liquid  58  and cleans free compounds. Then, the urea is passed into the CEA detecting cavity via the urea inlet  65 , reacts with the urease in the compound structure on the sensor, and leads to a change in pH, and the change in pH is related with the amount of the CEA antigen  77  in the condensate. Thereafter, the CEA-LAPS sensor  68  detects the change in pH, and finally the amount of the CEA antigen in the condensate is obtained. 
         [0131]    As shown in  FIG. 11 , the CEA-LAPS sensor  68  consists of a Si substrate  72 , a SiO 2  layer  73 , a Si 3 N 4  film  74 , a nanolayer  75 , and a biotin layer  76 . The SiO 2  layer  73  and the Si 3 N 4  film  74  are in turn deposited on the Si substrate  72  by the chemical vapor deposition and the photolithography, and the nanolayer  75  and the biotin layer  76  are formed on the surface of the Si 3 N 4  film  74  by the chemical coating method. Both the detecting electrode  67  and the second working electrode  69  are connected with a bias voltage  71 . 
         [0132]    A particular working process is as follows. On the surface of the CEA-LAPS sensor  68  are disposed the nanolayer  75  and the biotin layer  76 . At this point, the condensate flows into the CEA detecting cavity, the CEA antigen  77  in the condensate bonds with the biotin layer  76  via a covalent bond, and affixs to the surface of the CEA-LAPS sensor  68 . Then, the CEA antibody-avidin  79  and the CEA antibody-urease  78  flow into the CEA detecting cavity, and bonded with the CEA antigen  77 , forming a sandwich structure as shown in the figure. Then, the washing liquid cleans out extra CEA antibody-urease  78 , and only leaves the sandwich structure consisting of the CEA antigen  77 , the CEA antibody-urease  78  and the CEA antibody-avidin  79  on the CEA-LAPS sensor  68  in the CEA detecting cavity. Then, the urea flows into the CEA detecting cavity, reacts with the urease on the sandwich structure, and leads to a change of pH, and the change in pH is related with the amount of the CEA antigen  77  in the condensate. The CEA-LAPS sensor  68  obtains the amount of the CEA antigen  77  in the condensate by detecting the change of pH.