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Objective:To measure the influencing factors associated with the analysis of 226Ra gamma spectra in order to obtain more acurate and precise measuring result on a basis of further optimizing the gamma spectrometry method for 226Ra activity. Methods:A laboratory-based HPGe gamma spectrometer was used to carry out the studies on tracking measurement of sample sealing time, measurement of background fluctuation with lead shielding, analytical method, and selection of characteristic gamma ray energy peak of its daughter nuclides in 226Ra measurement. Results:After the sample was sealed for 12 d, the decay products of 226Ra- 222Rn basically reached equilibrium. The day and night fluctuations of 222Rn in the shielded lead room were obvious but had no obvious regularity. The way of filling nitrogen into the shielded lead room could reduce or avoid the influence of background fluctuations. For 31 soil samples measured after 23 days of sealing, the result of using the efficiency curve method showed that the 226Ra result calculated from the 351.9 keV energy peak were generally higher than the 609.3 keV energy peak, and the higher ratio ranged from 8.0% to 20.7%. The result of relative comparison method showed that the deviation ratio of the two peaks ranged from -4.1 % to 10.3 %. Conclusions:It is recommended to consider the uncertainty attributed from decay equilibrium about 4 % of measured at 12 d after the sample is sealed. When filling nitrogen through the shielded lead chamber to avoid background fluctuations, attention must be paid to the matching relationship between the volume of the lead chamber and the nitrogen filling flow. When the efficiency curve method is used to analyze the activity of 226Ra, the 214Bi ( 609.3 keV ) energy peak has the effect of cascade coincidence addition, so 214Bi(609.3 keV) energy peak should be avoided. When the relative comparison method is used to analyze the activity of 226Ra, both two energy peaks of 214Pb ( 351.9 keV ) and 214Bi ( 609.3 keV ) can be used.
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OBJECTIVE To establish t he method for determining the concentrations of fluoxetine ，norfluoxetine and sertraline in human placental perfusate method and their placental permeability. METHODS Using glyburide as internal standard ，the samples were pretreated by protein precipitation method and detected by ultra-fast liquid chromatograph-mass spectrometer/mass spectrometer （UFLC-MS/MS）. The determination was performed on Synergi TM Hydro-RP 80A LC column with mobile phase consisted of water （containing 0.1％ formic acid ）-acetonitrile（containing 0.1％ formic acid ）at the flow rate of 0.70 mL/min，with a gradient elution. The column temperature was set at 40 ℃，and sample size was 5 μL. Detection was performed with electrospray ionization source in multipl e reaction monitoring mode . The ion pairs for quantitative analysis we re m/z 309.9→148.1（fluoxetine），m/z 296.0→134.4 （-167）， （norfluoxetine），m/z 306.1→159.0 （sertraline），m/z 493.9→ No.2018FE001（-207），（internal standard ）. The perfusion model of singal placenta under bidrectional cardiopulmonary bypass was established. Fluoxetine （160 ng/mL），norfluoxetine（160 ng/mL）， sertraline（100 ng/mL）and antipyrine （positive control ，ng/mL）were added into the maternal perfusate. The concen- 65324888 trations of fluoxe tine， norfluoxetine and sertrali ne were measured by above UFLC-MS/MS at 0，10，20，30，45，60，90，120，150 and 180 min of circulation ，and the placental permeability was calculated. RESULTS The linear range of fluoxetine ，norfluoxetine and sertraline were 5.00-500 ng/mL（all r＞ 0.990），and the lower limits of quantification were all 5.00 ng/mL. The RSDs of intra-day and inter-day were all less than 14.0％， and relative error ranged －9.6％ to 14.7％. The relative error of stability test was －4.0％ to 11.0％；the residual effect ，extraction method and matrix effect did not affect the quantitative analysis of the substance to be tested. Totally 31 perfusion model of human placenta under cardiopulmonary bypass were successfully established ，including 15 fluoxetine and norfluoxetine perfusion ，10 sertraline perfusion and 6 antipyrine perfusion. After 3 hours of perfusion ，the average placental permeability of fluoxetine ， norfluoxetine and sertraline were （8.74 ± 1.67）％ ，（10.70 ± 4.81）％ ，（5.90 ± 1.25）％ ，respectively. CONCLUSIONS The established UPLC-MS/MS is simple ，sensitive and accurate. It can be used for determination of fluoxetine ，norfluoxetine and sertraline in human placental perfusate. Fluoxetine ，norfluoxetine and sertraline can pass through the placenta ，but sertraline has a lower placental permeability.
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Objective @#To establish a microwave-assisted digestion-inductively coupled plasma mass spectrometry (ICP-MS) with an octopole reaction system for simultaneous determination of six heavy metals in peanuts, including Cr, Ni, As, Cd, Pb, Hg. @*Methods @#Peanut samples were shelled and crushed evenly, and 0.350 0 g was accurately weighed and digested with 5 mL nitric acid and 1 mL hydrogen peroxide in a digestion tank. Following microwave-assisted digestion, pure water was used to quantify the samples, and internal standards and an octopole reaction system were used to remove the interference. Then, the contents of six heavy metals were determined in peanuts by ICP-MS. The accuracy and precision of ICP-MS were evaluated using national criteria ( GBW 10013 and GBW 10044 ) and spike-and-recovery testing. @*Results @#The six heavy metals showed good linearity at the selected linear range ( r≥0.999 8 ). The detection limits of ICP-MS ranged from 0.001 4 to 0.023 8 ng/mL, and the spike-and-recovery rates ranged from 94.7% to 98.8%, with the relative standard deviations ranging from 0.7% to 3.6%. In addition, the determination results of the standard reference materials were all within the normal reference range. The detection of six heavy metals was 100.0% in 60 peanut samples, and the contents of six heavy metals were all low.@*Conclusion @#The established ICP-MS assay is feasible for simultaneous determination of multiple heavy metals in peanuts.
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Objective:To simulate the effects of different thyroid-neck phantoms and monitoring positions on the detection efficiency of portable γ spectrometer, and to provide guidance for more accurate on-site measurement of 131I activity in the human thyroid. Methods:Based on the models of 4 typical thyroid-neck phantoms and a 3-inch NaI (TI) γ spectrometer used for the measurement of 131I in the thyroid and combined with the possible field monitoring scenarios, the Monte Carlo method was used to simulate and calculate the detection efficiency of the spectrometer under different conditions of monitoring distance, thyroid depth and thyroid volume. Results:The detection efficiency decreased significantly with the increase in the distance between the detector and the neck surface. The efficiency close to the neck surface was about 15 times that at 15 cm away from the neck surface. The detection efficiency decreased significantly with the increase in thyroid depth. When it was measured at the surface of the neck, the detection efficiency of thyroid at depth of 2 mm was about 3.6 times that of 30 mm. The detection efficiency decreases with the increase in thyroid volume. When it was measured at the neck surface, the detection efficiency of thyroid with 1 ml volume was 1.71 times that with 30 ml. The detection efficiency decreased with the center-point offset of the detector, especially at the neck surface, an offset of 2 cm would reduce the detection efficiency by about 15%.Conclusions:Not only the measurement distance used in calibration, but also the information of the depth and volume of thyroid in the neck-thyroid phantom, is important to know in advance for an accurate measurement of 131I activity in thyroid by using a portable gamma spectrometer.
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【Objective】 To establish and optimize a method for the determination of aluminum (Al) residue by inductively coupled plasma mass spectrometry (ICP-MS). 【Methods】 Nitric acid solution was used to treat samples and standards. The concentration of nitric acid solution and equipment parameters were optimized, and the specificity, linearity, repeatability, accuracy, detection limit, quantitative limit and intermediate precision of the optimized detection method were investigated to confirm whether it was suitable for the determination of Al residue in human serum albumin. 【Results】 The concentration of nitric acid was 5%, and digest time was 4 h. The equipment condition of ICP-MS was as follows: RF power: 1600 W, sampling depth: 10 mm, atomizer / carrier gas flow rate: 1.0 L/ min, compensation flow rate: 0.5 L/ min, experimental mode: standard mode, integration time: 0.2 s, data acquisition: 3 times. Specificity: The recoveries of Al: 92% (high concentration, RSD=3.5%), 98% (low concentration, RSD=4.9%). Linearity: In the range of (0~40) μg/L, the correlation coefficient between concentration and optical energy signal (CPS) of standard / sample were higher than 0.999 0. Accuracy/ Repeatability: The recoveries of sample (3 concentration): 108% (RSD=4.7%), 110% (RSD=4.9%) and 110% (RSD=2.8%). The detection limit was 0.006 μg/L, and the quantitation limit was 0.019 μg/L. Intermediate precision: personnel factor and date factor, P>0.05, RSD (12 times)=2%. Comparison between ICP-MS and atomic absorption spectrometry (AAS): the deviation between ICP-MS and AAS was 8%, and that of samples was 3%, with no significant difference noticed between the two methods. 【Conclusion】 After optimization, ICP-MS method has shown good performance in terms of specificity, linearity, repeatability, accuracy, detection limit, quantitative limit and intermediate precision, and is suitable for the determination of Al residue in human albumin products of our company.
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Objective:To investigate the differences in applicability of both the portable high-purity germanium (HPGe) γ spectrometer and the portable lanthanum bromide (LaBr) γ spectrometer for measuring thyroid 131I activity and internal exposure monitoring for radiation workers. Method:Both DETECTIVE-DX100-KT portable HPGe γ spectrometer and InSpector 1000 portable LaBr γ spectrometer were used to measure the 131I content in thyroid of radiation workers for comparison of the measuring result, minimum detectable activity (MDA) and corresponding annual committed effective doses between two types of spectrometers. Results:The detection rate of 131I in thyroid of radiation workers was 67.7% for HPGe γ spectrometer and 26.2% for LaBr γ spectrometer, respectively. The MDA was 12.26-14.74 Bq (measuring time: 3-5 min) for HPGe γ spectrometer and 56.56-80.37 Bq for LaBr γ spectrometer (measuring time: 2-4 min). The annual committed effective dose corresponding to MDA was 0.07-0.08 mSv (3-5 min) for HPGe and 0.31-0.45 mSv (2-4 min) for LaBr, respectively, in the case of using chronic continuous intake mode and 7 d monitoring period. Conclusions:The minimum detectable activity (MDA) of the two types of portable spectrometers could meet the requirements specified in GBZ 129-2016 Specifications for individual monitoring of occupational internal exposure for thyroid monitoring equipment. The two types of spectrometers could be used for routine monitoring of internal contamination. The difference between the monitoring result of LaBr γ and HPGe γ spectrometers might be due to such factors as large uncertainty in short measuring time and low activity concentrations, incomplete identical of distance between probe and neck, probe angle setting, different response of equipment to the environment, background deduction method.
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@#<b>Objective</b> To measure the specificactivity of natural and synthetic radionuclides in the environmental soil of Panjin, China and determine the content of radionuclides in the surface soil, and to conduct a scientific assessment of the radiation health risks of residents in this area. <b>Methods</b> Thirty-one surface soil samples were collected within the jurisdiction of Panjin, and a high-purity germanium detector was used for γ spectrum analysis to obtain the content of radionuclides and the current environmental radioactivity level. The two independent samples mean <i>t</i>-test was used to compare the specific activity data of radionuclides in soil samples between Panjin and Liaoning Province or China. <b>Results</b> The meanspecific activities of natural radionuclides <sup>238</sup>U, <sup>226</sup>Ra, <sup>232</sup>Th, <sup>40</sup>K, and synthetic radionuclide <sup>137</sup>Cs in the surface soil samples of Panjin were 18.7 Bq/kg, 19.6 Bq/kg, 23.5 Bq/kg, 604.6 Bq/kg, and 0.9 Bq/kg, respectively. <b>Conclusion</b> The specific activities of natural and synthetic radionuclides in the surface soil samples of Panjin Area at the background level, causing a very low health risk to the people in this area.
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ObjectiveIn order to establish a systematic quality evaluation system for Fritillariae Cirrhosae Bulbus adulteration， portable near-infrared （NIR） spectroscopy was used to identify Fritillariae Cirrhosae Bulbus and its adulterants and detect their adulteration quantity. MethodA total of 72 batches of Fritillariae Cirrhosae Bulbus samples were collected and 570 batches of adulterated products （dry bulbs of Fritillaria thunbergii， F. ussuriensis， F. pallidiflora and F. hupehensis， Bulbus Tulipae， flour） were prepared， NIR spectral data of samples were collected by the portable NIR spectrometer. Linear discriminant analysis （LDA） was used to establish the qualitative correction models of Fritillariae Cirrhosae Bulbus-adulterants and adulterants of different categories， partial least squares （PLS） was used to establish the quantitative correction models of adulteration quantity of different kinds of adulterants. ResultThe recognition rates of qualitative analysis model of Fritillariae Cirrhosae Bulbus and its adulterants were 99.49% （calibration set） and 100.00% （validation set）， respectively. In different adulterant models， the recognition rates of calibration set and validation set were 70.47% and 73.68%， respectively. Moreover， the correlation coefficients of validation set （R2P） of the six quantitative models of adulteration ratio were 0.840 2 （Fritillariae Cirrhosae Bulbus adulterated with F. thunbergii dry bulbs）， 0.960 2 （Fritillariae Cirrhosae Bulbus adulterated with F. ussuriensis dry bulbs）， 0.765 7 （Fritillariae Cirrhosae Bulbus adulterated with F. pallidiflora dry bulbs）， 0.902 5 （Fritillariae Cirrhosae Bulbus adulterated with F. hupehensis dry bulbs）， 0.957 4 （Fritillariae Cirrhosae Bulbus adulterated with Bulbus Tulipae）， 0.976 1 （Fritillariae Cirrhosae Bulbus adulterated with flour）， the root mean square error of prediction （RMSEP） were 10.948 5， 5.463 9， 13.256 4， 8.549 2， 5.655 3， 4.235 6， respectively. The two qualitative models and six quantitative models showed good prediction performance. ConclusionThe portable NIR spectroscopy can be used to identify Fritillariae Cirrhosae Bulbus and its adulterants in real time， the method is rapid and accurate， which can meet the requirements of nondestructive identification of Fritillariae Cirrhosae Bulbus on site.
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ObjectiveTo prepare pesticide residues in fruit matrix samples that meet the requirements of homogeneity and stability for the proficiency test. MethodsThe pollution-free apple was selected as the main raw material to prepare the pesticide residue proficiency test samples of myclobutanil and procymidone， and to evaluate the homogeneity and stability. The results of the proficiency test were assessed using robust analysis and Ζ value. ResultsThe homogeneity and stability of the reference materials met the relevant requirements. Among 109 laboratories participated in the proficiency testing， 107 （98.2%） laboratories had satisfactory results. Suspicious test results were reported only in two laboratories， one laboratory for each of the two assessment items. ConclusionAn apple powder matrix sample with pesticide residues is successfully prepared for proficiency test， and could provide an evaluation tool for pesticide residue testing laboratories.
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An integrated digital magnetic resonance imaging spectrometer was proposed in this study. By using the FPGA chip Artix7 200T, timing control, data processing, digital frequency conversion and phase control were implemented into a single-chip, thus effectively improved timing accuracy and phase accuracy, while avoided the structural design complexity caused by multi-board connection and improved system integration and imaging quality.
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Equipment Design , Magnetic Resonance ImagingABSTRACT
OBJECTIVE: To explore a method for detecting volatile organic compounds(VOCs) in air by a portable gas chromatography-mass spectrometer(GC-MS). METHODS: A portable GC-MS hand-held probe was used for sampling and detection. All effluent components were qualitatively analyzed by the standard spectral library of the United State National Institute of Standards and Technology. The percentage of peak area of the component was calculated by normalization method. The static distribution method was adopted in the semi-quantitative and quantitative analysis using nitrogen as the diluting gas to prepare different mass concentration of 13 kinds of VOCs in the mixed standard gas. The retention time and characteristic ions were used for qualitative analysis, and the quantitated full scanning mode was used for quantitative analysis.RESULTS: The minimum detected mass concentration of the 13 chemical harmful factors was 0.02-0.10 mg/m~3, and the minimum quantitative mass concentration was 0.07-0.38 mg/m~3. The recovery rate was 84.76%-116.56%, and the within-and between-run relative standard deviations were 4.10%-12.50% and 8.17%-14.36%, respectively. CONCLUSION: The portable GC-MS instrument could be used for qualitative alalysis, peak area percentage determination, semi-quantitative and quantitative analysis of VOCs in the workplace air or sudden chemical poisoning accidents.
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Modern chromatography - mass spectrometer (MS) technology is an essential weapon in the exploration of traditional Chinese medicines (TCMs) which is based on the “effectiveness-material basis-quality markers (Q-markers)”. Nevertheless, the hardware bottleneck and irregular operation will limit the accuracy and comprehensiveness of test results. Chemometrics was thereby used to solve the existing problems: 1) The method of ‘design-modeling-optimization’ can be adopted to solve the multi-factor and multi-level problems in sample preparation/ parameter setting; 2) The approaches of signal processing can be used to calibrate the deviation from retention time (rt) dimension and mass-to-charge ratio (m/z) dimension in different types of instruments; 3) The methods of multivariate calibration and multivariate resolution can be utilized to analyze the co-eluting peaks in complex samples. When the researchers need to capture essential information on raw data sets extracting the higher level of information on essential features, 1) The significant components which affects the drug properties/efficacy can be find by the pattern recognition and variable selection; 2) Fingerprint-efficacy modeling is explored to clarify the material basis, or to screen out the Q-markers of biological significance; 3) Chemometric tools can apply to integrate chemical (metabolic) fingerprints with network pharmacology, bioinformatics, omics and others from a multi-level perspective. Under these programs, the qualitative/quantitative works will achieve in chemical (metabolic) fingerprint and metabolic trajectories, which leads to an accurate reflection of “material basis and Q-markers” in TCMs. Likewise, an in-depth hidden information can be disclosed, so that the components of drug properties/efficacy will be found. More importantly, multidimensional data can be integrated with fingerprints to acquire more hidden information.
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Beclomethasone is an effective glucocorticoid, and beclomethasone-aptamer is a short single-stranded DNA with affinity and specificity to beclomethasone. The interaction between them is still unclear. The study of the interaction between aptamers and beclomethasone has a certain significance for the application of aptamers. In this study, high-resolution Fourier transform ion cyclotron resonance mass spectrometer (FT-MS) and molecular docking simulation technology were used to study the interaction between aptamer and beclomethasone. Firstly, under the optimized conditions of high-resolution mass spectrometry parameters, the complex of aptamer and beclomethasone was detected by the negative ion scanning mode with the electrospray ion source. Based on the results of high-resolution mass spectrometry, most of the compounds were -8-valent ions, and their dissociation constant K
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The components of volatile oils are generally complex, and they often have the functions of divergent dissolving surface, insecticidal and antibacterial. However, there are few reports on bacteriostasis, anti-inflammation and antioxidation roles of volatile oils of Pelargonium graveolens L'Herit. The volatile oil of Pelargonium graveolens L’Herit. was extracted by steam distillation, and GC-MS and peak area normalization analysis showed that it mainly contained 30 compounds, and the identified components accounted for 90.26% of the total peak area. The volatile oil of Pelargonium graveolens L'Herit. has a certain inhibitory effect on Candida albicans and Staphylococcus aureus, especially on Candida albicans. The diameter of the bacteriostatic zone is 15.55±1.53 mm by using the oxford cup method. Dexamethasone and low, middle and high doses of volatile oils of Pelargonium graveolens L'Herit. were given after the RAW264. 7 cell inflammatory model and was induced by lipopolysaccharide (LPS = 10.0 μg/mL). ELISA assays showed that it could effectively reduce the expression of IL-1β and TNF-α in inflammatory cells, and the effect of high doses was similar to that of IL-1β and TNF-α in the dexamethasone group. GC-MS was successfully used to determine and identify the chemical constituents of volatile oils from Pelargonium graveolens L'Herit. in this study. We show that the volatile oil of Pelargonium graveolens L'Herit. had certain bacteriostatic activity and effectively reduces the secretion of IL-1β and TNF-α by inflammatory cells. It provides an experimental basis for the development and utilization of volatile oils from Pelargonium graveolens L'Herit.
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This paper investigated the effects of regular aerobic exercise on protein oxidative stress and apoptosis in aging rat striatum, and further analyzed its target proteins and mechanism based on differential carbonylation proteomics. Totally 24 specific pathogen-free (SPF) 23-month-old male Sprague-Dawley (SD) rats were randomly divided into aged sedentary control group (Con-SED, n = 12) and aged regular aerobic exercise runner group (Aero-EXE, n = 12). The medium intensity of regular aerobic exercise model: The intensity of maximum oxygen consumption (VO
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Objective The effect of sieved particle size and equilibration time of soil samples on the measurement of radionuclides was studied to improve the accuracy of the specific activity of radionuclides in soil samples measured by gamma spectrometer. Methods The collected soil samples were dried and divided into four parts. After sieved with width of the mesh 2.0 mm, 1.0 mm, 0.5 mm and 0.25 mm respectively, they were filled into sample containers and sealed. The activity concentrations of 226Ra, 210Pb, 228Ra, 40K and 137Cs in different sieved soil samples were then measured at the sealed interval of 0, 4, 8, 12, 16, 21, 25 and 29 days by HPGe gamma-ray spectrometry respectively. Results The coefficients of variation ofthe specific activities of 226Ra, 210Pb, and 228Ra in soil samples measured at different equilibration intervals range from 0.9% to 4.3%. The coefficients of variation of the specific activities of 226Ra, 210Pb, 228Ra, 40K and 137Cs in soil samples with different sieved particle sizes range from 3.7% to 14.1%. Conclusion When the specific activities of radionuclides are determined by gamma-ray spectrometer, the effect of the sieved particle size on the measurement result must be considered, and its impact is higher than the equilibration time. This study is very useful for improving the accuracy of the determination of radionuclides in soil sample using gamma-ray spectrometer.
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Objective Based on the lanthanum bromide scintillator detector, the calculation method of G(E) function was developed to measure the air absorbed dose rate. Methods Firstly, the gamma energy spectrumof the lanthanum bromide detector were simulated and the response functions with different energies were determined with Monte Carlo simulation method. Then, the G(E) function was calculated by the least square method. Finally, the air absorbed dose rate measured by the lanthanum bromide detector using G(E) function conversion method was compared with the theoretical calculation value based on the point source experiments. Results The experimental verification results showed that the relative deviation between thecalculated value with G(E) function and the theoretical calculation value wasmostly controlled within ± 6%, which verified the accuracy of G(E) function. Conclusion The results showed that the method of G(E) function could be applied to calculate the gamma radiation dose rate based on the in-situ the gamma spectrum with LaBr3 detector.
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Objective To investigate the effects of particle size, wind speed and dumping velocity on aerosol concentration distribution during powder dumping in a reprocessing plant. Methods CeO2 powder was selected as the substitute material of PuO2. FLUENT software was used to calculate the pouring process of CeO2 powder under different operation conditions. Then the aerosol concentration distribution under different dumping speeds was measured by particle size spectrometer to verify the accuracy of simulation results. Results The particles with small particle size are more likely to be separated from the mainstream area by the drag force of the surrounding gas, and the radius of the diffusion range also increases with the decrease of the particle size. 2) When the ventilation speed is less than 1 m/s, the dust lifting can be reduced and the concentration of dust particles in the chamber can be reduced to a certain extent. 3) In the process of powder dumping, the spoon is rotated anticlockwise at a speed of 100° in 2～3 s, and less dust aerosol is produced on the right side of the tray. Conclusion When operating the powder particles with smaller particle size, more attention should be paid to the monitoring of aerosol at different positions; the change of air inlet velocity makes the flow field in glove box more complex, and the volume fraction of dust particles is related to the size and location of vortex formed by airflow. The greater the wind speed, the greater the impact on the powder dumping process. The experimental results are basically consistent with the simulation results, and the results show that the lower the dumping speed, the smaller the aerosol concentration near the tray.
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Objective To apply InSpector 1000 portable γ spectrometer and its corresponding supporting software to the monitoring of thyroid 131I activity of radiation workers, and to estimate the internal radiation dose of medical staff in nuclear medicine department. Methods The spectrometer was calibrated and taken to participate in the 2018 thyroid radioactive iodine intercomparison program initiated by Lawrence Livermore National Laboratory in the United States to ensure the accuracy of the measurement; the spectrometer was used to measure 131I activity ofthe radiation workers of the nuclear medicine departments of two grade-A tertiary hospitals in Beijing and Jinan to verify the feasibility of the method. Results The InSpector 1000 portable γ spectrometer was qualified for international intercomparison. Measurement results from the grade-A tertiary hospital in Beijing showed that the thyroid 131I activity of each of 10 radiation workers was below the detection limit (33.30 Bq). Measurement results from the grade-A tertiary hospital in Jinan showed that the thyroid 131I activities of the 4 radiation workers were 64.05 Bq, 160.77 Bq, 416.67 Bq, below the detection limit (35.18 Bq) respectively, and of 3 of the 4 subjects 131I was detected in the thyroid, and their corresponding thyroid accumulative organ doses were 0.70 μSv, 1.77 μSv, and 4.58 μSv, respectively. Conclusion InSpector 1000 portable γ spectrometer has a strong feasibility for thyroid 131I monitoring of radiation workers in nuclear medicine. The spectrometer has a good application prospect in the field of radiation monitoring, and can play an important role in the field of radiation protection and nuclear emergency detection.
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Objective To establish a method using supramolecular solvent and gas chromatography-tandem mass spectrometry （GC-MS/MS） to analyze 9 benzodiazepines in urines. Methods Urine samples containing 9 benzodiazepines reference substance were subjected to liquid-liquid extractions with supramolecular solvent, which consisted of tetrahydrofuran and 1-hexanol. The solvent layer was evaporated to dryness by stream of nitrogen. The residue was reconstituted with methanol, and GC-MS/MS analysis was performed on it. The way of data collection was multiple reaction monitoring （MRM） mode; internal standard method was employed for quantification. Results In urine samples, when the range of mass concentration was 1-100 ng/mL for diazepam, midazolam, flunitrazepam and clozapine, 5-100 ng/mL for lorazepam and alprazolam, 2-100 ng/mL for nitrazepam and clonazepam, and 0.2-100 ng/mL for estazolam, respectively, good linearities were obtained, correlation coefficients were 0.999 1-0.999 9, the lower limits of the quantifications ranged from 0.2 to 5 ng/mL, the extraction recovery rates were 81.12%-99.52%. The intra-day precision ［relative standard deviation （RSD）］ and accuracy （bias） were lower than 9.86% and 9.51%, respectively; the inter-day precision （RSD） and accuracy （bias） were lower than 8.74% and 9.98%, respectively. Nine drugs in urine samples showed good stability at ambient temperature and -20 ℃ within 15 days. The mass concentrations of alprazolam in urine samples obtained from 8 volunteers who took alprazolam tablets orally within 8-72 h after ingestions ranged from 6.54 to 88.28 ng/mL. Conclusion The supramolecular solvent extraction GC-MS/MS method for analysis of 9 benzodiazepines in urines provided by this study is simple, fast, accurate and sensitive, which can provide technical support for monitoring of poisoning by benzodiazepines for clinical treatment and judicial identification.