Establishment of Fluorescence Quantitative RT-PCR Assay for Detection of Equine Arteritis Virus

[Objective]The paper was to establish a fluorescence quantitative RT-PCR method for detection of equine arteritis virus(EAV).[Method]Primers and probes were developed for the EAV ORF7 gene sequence,and the reaction system was optimized.Standard curves were established,leading to the initial development of the EAV fluorescence quantitative RT-PCR assay.The accuracy,specificity,and sensitivity of this method were subsequently evaluated.[Result]The EAV fluorescence quantitative RT-PCR assay demonstrated optimal performance at an annealing temperature of 61 C,with a final concentration of primer and probe set at 0.6μmol/L.The plasmid standard demonstrated a strong linear correlation with Ct values within the range of 1.6×10^(7)-1.6×10^(2)copies/μL.The equation of the standard curve was determined to be y=-2.68x+32.88,with an R^(2) value of 0.9927.Consequently,the EAV fluorescence quantitative RT-PCR assay was successfully established.The methodology employed was effective in detecting EAV,Theileria equi,equine herpesvirus-1(EHV-1),equine herpesvirus-4(EHV-4),and equine influenza virus(EIV).The findings indicated that the method was specifically capable of detecting EAV,while the other pathogens tested yielded negative results.The method demonstrated a high degree of specificity.It was employed to detect the standard plasmid cRNA synthesized through in vitro transcription following a 10-fold dilution.The results indicated that the minimum detection limit of the method was 1.6×10^(2) copies/μL,and it exhibited high sensitivity.The coefficient of variation,both within and between groups,was maintained at 1.8%,indicating good reproducibility.In this study,the fluorescence quantitative RT-PCR assay developed was utilized alongside the EAV fluorescence quantitative RT-PCR assay established by previous researchers to analyze a total of 234 clinical samples.Both methods yielded a positive detection rate of 14.1%,and the coincidence rate between the two techniques was found to be 100%.[Conclusion]The fluorescence quantitative RT-PCR assay developed in this study offers a novel approach and concept for the prevention and control of equine viral arteritis(EVA).

Detection of Survivin mRNA in nasopharyngeal carcinoma by real-time fluorescence quantitative RT-PCR

Objective： To establish the method of real time fluorescence quantitative RT-PCR for detecting the expression of Survivin mRNA in nasopharyngeat carcinoma （NPC） tissues. Methods： The total RNA was extracted from NPC cell line CNE-2 and tissues with Trizol and then been transcribed reversely to cDNA, a method of real time fluorescence quantitative RT-PCR for detecting the expression of Survivin mRNA in NPC tissues had been established, in which chronic nasopharyn-gitis patients＇ nasopharynx tissues treated as control group. Results： The expression of Survivin mRNA all could be detected either in CNE-2 cells, NPC tissues or in chronic nasopharyngitis patients＇ nasopharynx tissues, and there was higher the expression level of Survivin mRNA in NPC tissues than which in chronic nasopharyngitis patients＇ nasopharynx tissues, the difference was significant （P 〈 0.01）. The expression of Survivin mRNA could be detected both in stage Ⅰ ＋ Ⅱ and stage Ⅲ ＋ Ⅳ NPC, and there was no significant difference in relative quantifications of gene expression between these two groups （P 〉 0.05）. There was no relationship between Survivin mRNA expression and age and sex of NPC patients （P 〉 0.05）. Conclusion： Real time fluorescence quantitative RT-PCR is a rapid, effective and high sensitive method for detecting the expression of Survivin mRNA in NPC tissues. The overexpression of Survivin mRNA may play some roles in pathogenesis of NPC.

Detection and clinical significance of multidrug resistance-1 mRNA in bone marrow cells in children with acute lymphoblastic leukemia by real-time fluorescence quantitative RT-PCR

Objective： Multidrug resistance（MDR） is one of the most important reasons for treatment failure and recurrence of acute leukemia. Its manifestations are different in children with acute lymphoblastic leukemia（ALL） which may be due to different detection methods. This study was to detect the expression of MDR1 mRNA in bone marrow cells of children with ALL by real-time fluorescence- quantitative reverse transcription polymerase-chain reaction（FQ-RT-PCR）, and combine minimal residual desease（MRD） detection by flow cytometry（FCM） and to study their relationship with treatment response and prognosis of ALL. Methods：The MDR1 mRNA levels in bone marrow cells from 67 children with ALL[28 had newly diagnosed disease, 27 had achieved complete remission（CR）, 12 recurrent] and 22 children without leukemia were detected by FQ-RT-PCR. MRD was detected by FCM. The patients were observed for 9-101 months, with a median of 64 months. Results：Standard curves of human MDR1 and GAPDH genes were constructed successfully. MDR1 mRNA was detected in all children with a positive rate of 100%. The mRNA level of MDR1 was similar among the newly diagnosed ALL group, CR group, and control group（P 〉 0.05）, but significantly higher in the recurrence group than that in newly diagnosed disease group and control group（0.50 ± 0.55 vs. 0.09 ± 0.26 and 0.12 ± 0.23, P〈 0.05）. 54 ALL patients were followed up, and it was found that MDR1 mRNA level was significantly higher in ALL patients within 3 years duration than that of ALL patients with 3-6 years and over 6 years duration（0.63 ± 0.56 vs. 0.11 ± 0.12 and 0.04 ± 0.06, P〈 0.01）. For the 28 children with newly diagnosed disease, the MDR1 mRNA level was similar between WBC 〉 50 ~ 109 group and WBC〈50 × 10^9 group（P〉 0.05）. In the 33 CR patients, the MDR1 mRNA level was significantly higher in MRD〉10a group than that in MRD〈10a group（0.39 ± 0.47 vs. 0.03 ± 0.03, P 〈 0.05）. Conclusion：The sensitivity and specificity of FQ-RT-PCR in detecting MDR1 mRNA in bone marrowy cells of children with ALL patients are high. MDR1 mRNA is expressed in children with and without leukemia. MDR1 mRNA is highly expressed in the CR ALL patients with high MRD, recurrence and short duration（within 3 years）. Monitoring MRD and the MDR1 mRNA level might be helpful for individual treatment.

Synchronous Detection of DNA/RNA of Four Shrimp Viruses by Real-time Fluorescence Quantitative RT-PCR

[ Objective] This study aimed to establish a simultaneous detection method of shrimp viruses by real-time fluorescence quantitative RT-PCR, to improve the efficiency of inspection and quarantine. [ Method] A novel real-time fluorescence quantitative RT-PCR assay was established and optimized for simultaneously detecting DNA/RNA of four shrimp viruses （WSSV, IHHNV, TSV and YHV ）. [ Result] The optimized real-time fluorescence quantitative RT-PCR system gener- ated typical amplification curves with high amplification efficiencies （E = 1.06, 1.07, 0.92 and 0.92, respectively）, good hnear relationship （ r = 1 ）, uniform repeatability （ standard deviation = 0.05 - 0.46 ; variation coefficient = 0.26% - 1.62% ） and high sensitivity, exhibiting no significant differences compared with re- al-time fluorescence quantitative PCR （average error of Ct value = 0.04 -0.40; T = 0.53 -2.50; P 〉 0.05 ）. The total detection time was about 1 h. [ Conclusion] The optimized real-time fluorescence quantitative RT-PCR system can be used for rapid detection of WSSV, IHHNV, TSV and YHV.

TaqMan real-time fluorescent quantitative RT-PCR in detection of macrophage inflammatory protein-2γ mRNA in myocarditis murine

Objective: To study the role of macrophage inflammatory protein (MIP)-2γ in myocarditis pathogenesis in BALB/c mice. Methods: The relationship between the progression of Coxsarckie virus B3(CVB3) viral myocarditis and experimental autoimmune myocarditis and MIP-2γ mRNA expression in mouse was studied by TaqMan real-time fluorescent quantitative RT-PCR. Results: MIP-2γ mRNA expression rose on 3 to 5 d after CVB3 infection, reached peak on 7 d, and returned to normal level until 14 d, which corresponded well with the disease course. The MIP-2γ mRNA expression level rose significantly on the day 18 d after immunization with porcine cardiac myosin, which was consistent with pathological examination. Conclusion: MIP-2γ may be involved in the pathogenesis of myocarditis.

THE DETECTION OF MDR1 GENE EXPRESSION USING FLUOROGENIC PROBE QUANTITATIVE RT-PCR METHOD

Objective: To establish a fluoregenic probe quantitative RT-PCR (FQ-RT-PCR) method for detection of the expression of MDR1 gene in tumor cells and to investigate the expression of MDR1 gene in patients with lung cancer. Methods: The fluorogenic quantitative RT-PCR method for detection of the expression of MDR1 gene was established. K562/ADM and K562 cell lines or 45 tumor tissues from patients with lung cancer were examined on PE Applied Biosystems 7700 Sequence Detection machine. Results: the average levels of MDR1 gene expression in K562/ADM cells and K562 cells were (6.86±0.65)× 107 copies/μg RNA and (8.49±0.67)×105 copies/μg RNA, respectively. The former was 80.8 times greater than the latter. Each sample was measured 10 times and the coefficient variation (CV) was 9.5% and 7.9%, respectively. Various levels of MDR1 gene expression were detected in 12 of 45 patients with lung cancer. Conclusion: Quantitative detection of MDR1 gene expression in tumor cells was achieved by using FQ-RT-PCR. FQ-RT-PCR is an accurate, and sensitive method and easy to perform. Using this method, low levels of MDR1 gene expression could be detected in 24% of the patients with lung cancer.

The diagnostic significance of the detection of cytokeratin 19 mRNA by quantitative RT-PCR in benign and malignant pleural effusions

Objective: To evaluate the diagnostic significance of detecting cytokeratin 19 (CK19) mRNA by quantitative reverse transcription polymerase chain reaction (RT-PCR) in benign and malignant pleural effusions. Methods: CK19 mRNA was examined by quantitative RT-PCR and CK19 was detected by Enzyme-linked immunoadsorbent assay (ELISA) in 32 patients with malignant pleural effusions and 35 patients with benign pleural effusions. Results: On the threshold of 200 copies/μl, the positive rate of CK19 mRNA in patients with malignant pleural effusions was 62.5%. The positive rates of CK19 mRNA and CK19 in the malignant pleural effusions were significantly higher than those in the benign group (P<0.01). Furthermore, the positive rate of CK19 mRNA was higher than that of CK19 in the malignant group (P<0.05). Conclusion: Detection of CK19 mRNA can be a promising diagnostic marker in differential diagnosis of benign and malignant pleural effusions.

Reference genes for quantitative RT-PCR data in gastric tissues and cell lines

AIM:To evaluate the suitability of reference genes in gastric tissue samples and cell lines.METHODS:The suitability of genes ACTB,B2M,GAPDH,RPL29,and 18S rRNA was assessed in21 matched pairs of neoplastic and adjacent nonneoplastic gastric tissues from patients with gastric adenocarcinoma,27 normal gastric tissues from patients without cancer,and 4 cell lines using reverse transcription quantitative real-time polymerase chain reaction(RT-qPCR).The ranking of the best single and combination of reference genes was determined by NormFinder,geNorm,BestKeeper,and DataAssist.In addition,GenEx software was used to determine the optimal number of reference genes.To validate the results,the mRNA expression of a target gene,DNMT1,was quantified using the different reference gene combinations suggested by the various software packages for normalization.RESULTS:ACTB was the best reference gene for all gastric tissues,cell lines and all gastric tissues plus cell lines.GAPDH+B2M or ACTB+B2M was the best combination of reference genes for all the gastric tissues.On the other hand,ACTB+B2M was the best combination for all the cell lines tested and was also the best combination for analyses involving all the gastric tissues plus cell lines.According to the GenEx software,2 or 3 genes were the optimal number of references genes for all the gastric tissues.The relative quantification of DNMT1 showed similar patterns when normalized by each combination of reference genes.The level of expression of DNMT1 in neoplastic,adjacent non-neoplastic and normal gastric tissues did not differ when these samples were normalized using GAPDH+B2M(P=0.32),ACTB+B2M(P=0.61),or GAPDH+B2M+ACTB(P=0.44).CONCLUSION:GAPDH+B2M or ACTB+B2M is the best combination of reference gene for all the gastric tissues,and ACTB+B2M is the best combination for the cell lines tested.

Real-time Quantitative RT-PCR for CT9 Level in Human Cancer

CT9 is a recently cloned cancer-testis antigen, which is a member of the bromodomain and extraterminal family. Each member of this protein family contains two N-terminal bromodomain motifs. We investigated the distribution of CT9 in different tissues and the possibility for it to be used as a potential therapeutic target in cancer treament. By using the real-time RT-PCR method and 18SrRNA as an internal standard, we analyzed the CT9 expression in several normal human tissues and in the tissues of patients suffering from cancer. The result of this study shows that the highest level of mRNA is only present in testis tissue because the CT9 expression has not been detected in other normal tissues. In 6 of 10 cases of gastric adenocarcinoma, in 3 of 10 cases of esophageal squamous cell carcinoma, in 2 of 9 cases of endometrial carcinoma and only in 1 of 12 cases of brain cancer, the low level expression of CT9 was detected. In none of the 12 cases of cervical squamous cell carcinoma, the expression of CT9 was detected. Since the high level expression of CT9 is only found in the normal testis tissue, but the low expression in cancer tissues, for example tissues of cervical squamous cell carcinoma, brain cancer, endometfial adenocarcinoma, esophageal squamous cell carcinoma, we conclude that CT9 cannot be used as a cancer therapeutic target molecule for cervical squamous cell carcinoma, brain cancer, endometrial adenocarcinoma, esophageal squamous cell carcinoma.

Detecting PML-RARα transcript in acute promyelocytic leukemia using real-time quantitative RT-PCR

Background Real-time quantitative RT-PCR （RQ-PCR） assay has become a vital tool to monitor residual disease of leukemia, However, the complexity and standardization of RQ-PCR should never be overlooked and the results should be interpreted cautiously in clinical conditions. We aimed to assess the methodology of RQ-PCR and its clinical applications in monitoring molecular kinetics of 36 newly diagnosed cases of acute promyelocytic leukemia patients with t （15;17） from October 2004 to December 2005.Methods All the TaqMan probe-based RQ-PCR reactions and analysis were performed on an ABI-PRISM 7500 platform, The quantitation of PML-RARα transcripts was represented by the normalized quotient, that is, PML-RARα transcript copies divided by ABL transcript copies, According to induction therapy, the patients were classed into two groups： group 1 （n=23）, three-drug combination including arsenics, all-trans retinoic acid and mitoxantrone; and group 2 （n=13）.two-drug combination from all-trans retinoic acid, arsenics and mitoxantrone.Results The sensitivity of RQ-PCR was 1 per 105 cells and 5 copies of the PML-RARα transcript could be reproducibly detected, No false positive results occurred in 40 non-acute promyelocytic leukemia samples, Optimal amplification efficiency could be attained, which was determined by the slope of the standard curves （slope： -3.2 -- -3.7）. The inter-assay and intra-assay variation coefficients of the method were 1.01% and 0.56% respectively. Although the time to attain hematological complete remission was similar in both groups, the time to achieve molecular remission of group 1 was significantly shorter than that of group 2 （61 days vs 75 days, P=0.034）. The rate of molecular remission within 70 days was higher in group 1 than in group 2 （75.00% vs 38.46%, P=0.036）, Compared with pretreatment, median reduction of the PML-RARα transcript before first consolidation therapy differed significantly between group 1 and group 2 （log scale, 3.15 vs 2.31, P=0.024）, Interestingly, we found that PML-RARα transcript levels temporarily increased in bone marrow （7 patients） and peripheral blood （22 patients） samples of patients during induction therapy in both groups.Conclusions The RQ-PCR assay is reliable for the detection of PML-RARα transcripts. Arsenics, all-trans retinoic acid and mitoxantrone triad induction treatment of acute promyelocytic leukemia is superior to two-drug combination induction therapy in terms of the molecular response.

A quantitative RT-PCR assay for rapid detection of Eurasianlineage H10 subtype influenza A virus

Dear Editor,Influenza A viruses(IAVs)are single-stranded,negative sense RNA viruses.IAV subtype is determined on the basis of the viral surface glycoproteins,hemagglutinin(HA),and neuraminidase(NA).To date,18 HA and 11NA subtypes have been reported(Tong et al.,2012).

Identification of normalization factors for quantitative realtime RT-PCR analysis of gene expression in Pacific abalone Haliotis discus hannai

Quantitative real-time reverse transcription-polymerase chain reaction （qRT-PCR） is widely used in studies of gene expression. In most of these studies, housekeeping genes are used as internal references without validation. To identify appropriate reference genes for qRT-PCR in Pacific abalone Haliotis discus hannai, we examined the transcription stability of six housekeeping genes in abalone tissues in the presence and absence of bacterial infection. For this purpose, abalone were infected with the bacterial pathogen Fibrio anguillarum for 12 h and 48 h. The mRNA levels of the housekeeping genes in five tissues （digestive glands, foot muscle, gill, hemocyte, and mantle） were determined by qRT-PCR. The PCR data was subsequently analyzed with the geNorm and NormFinder algorithms. The results show that in the absence of bacterial infection, elongation factor-l-alpha and beta-actin were the most stably expressed genes in all tissues, and thus are suitable as cross-tissue type normalization factors. However, we did not identify any universal reference genes post infection because the most stable genes varied between tissue types. Furthermore, for most tissues, the optimal reference genes identified by both algorithms at 12 h and 48 h post-infection differed. These results indicate that bacterial infection induced significant changes in the expression of abalone housekeeping genes in a manner that is dependent on tissue type and duration of infection. As a result, different normalization factors must be used for different tissues at different infection points.

Incorporating empirical knowledge into data-driven variable selection for quantitative analysis of coal ash content by laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy(LIBS)has become a widely used atomic spectroscopic technique for rapid coal analysis.However,the vast amount of spectral information in LIBS contains signal uncertainty,which can affect its quantification performance.In this work,we propose a hybrid variable selection method to improve the performance of LIBS quantification.Important variables are first identified using Pearson's correlation coefficient,mutual information,least absolute shrinkage and selection operator(LASSO)and random forest,and then filtered and combined with empirical variables related to fingerprint elements of coal ash content.Subsequently,these variables are fed into a partial least squares regression(PLSR).Additionally,in some models,certain variables unrelated to ash content are removed manually to study the impact of variable deselection on model performance.The proposed hybrid strategy was tested on three LIBS datasets for quantitative analysis of coal ash content and compared with the corresponding data-driven baseline method.It is significantly better than the variable selection only method based on empirical knowledge and in most cases outperforms the baseline method.The results showed that on all three datasets the hybrid strategy for variable selection combining empirical knowledge and data-driven algorithms achieved the lowest root mean square error of prediction(RMSEP)values of 1.605,3.478 and 1.647,respectively,which were significantly lower than those obtained from multiple linear regression using only 12 empirical variables,which are 1.959,3.718 and 2.181,respectively.The LASSO-PLSR model with empirical support and 20 selected variables exhibited a significantly improved performance after variable deselection,with RMSEP values dropping from 1.635,3.962 and 1.647 to 1.483,3.086 and 1.567,respectively.Such results demonstrate that using empirical knowledge as a support for datadriven variable selection can be a viable approach to improve the accuracy and reliability of LIBS quantification.

Establishment of quantitative evaluation system for cochlear implant effectiveness for hearing-impaired children

Introduction:Cochlear implant is currently the most widely proven interventions for auditory rehabilitation for children with severe sensorineural hearing impairment.However,there are obvious limitations in these current evaluation methods.This study aims to develop an evaluation system for quantitatively evaluating the effectiveness of cochlear implants for hearing-impaired children.Methods:A correspondence questionnaire was developed based on an initial indicator system that was developed based on the literature focused on the evaluation of cochlear implant outcomes in children.Twenty-five experts in otology,clinical audiology,rehabilitation audiology,and mental health from nine provinces in China were consulted.The degree of authority and coordination of experts and the indicators and weights of the quantitative evaluation system were analyzed.Seventy-eight children aged 3–11 years after cochlear implantation were recruited from two centers in Hubei province to evaluate the reliability and validity of the quantitative evaluation system.Results:The opinions of experts converged after the second round of correspondence,and the coordination and authority of the expert consensus were met.The recall rate of the questionnaire was 100%for both rounds.Five secondary indicators,including auditory ability,verbal ability,behavioral assessment,learning capabilities,and quality of life,and 13 tertiary indicators were reserved for the evaluation of cochlear implant effectiveness.The weight of each indicator was calculated.The Cronbach’sαcoefficient of the quantitative evaluation system based on the standardized items was 0.930,and the three extracted common factors could explain 78.86%of the total variance.Conclusions:An expert consensus-based evaluation system that can quantitatively evaluate the effectiveness of cochlear implants in children has been developed with good reliability and validity.

Quantitative real-time RT-PCR detection for CEA, CK20 and CK19 mRNA in peripheral blood of colorectal cancer patients

This study is aimed at establishing a sensitive approach to detect disseminated tumor cells in peripheral blood and evaluate its clinical significance. A total of 198 blood samples including 168 from colorectal carcinoma (CRC) patients and 30 from healthy volunteers were examined by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) to evaluate the expression of carcinoembryonic antigen (CEA), cytokeratin 20 (CK20) and cytokeratin 19 (CK19) mRNA. CEA mRNA was detected in 35.8% of patients and 3.3% of controls, CK20 mRNA in 28.3% of patients and 6.7% of controls, and CK19 mRNA in 41.9% of patients and 3.3% of controls. CEA and CK20 mRNA positive ratio increased with the advancing Dukes stages, but there was no significant difference in positive ratio between any two stages (P>0.05). Also, relatively high positive ratio of CEA, CK20 and CK19 mRNA expression was observed in some CRC patients with earlier Dukes stages. A higher positive ratio was obtained when two or three detection markers were combined compared to a single marker. Our study indicates that quanti-tative real-time RT-PCR detection for CEA, CK20 and CK19 mRNA in peripheral blood is a valuable tool for monitoring early stage dissemination of CRC cells in blood circulation.

A Rapid and Sensitive One Step-SYBR Green Based Semi Quantitative Real Time RT-PCR for the Detection of peste des petits ruminants Virus in the Clinical Samples

A sensitive and rapid single step real time （rt） RT-PCR was standardized using one-step Brilliant SYBR Green kit for detection and semi-quantitation ofpeste des petitis ruminants virus （PPRV） using the virus RNA and matrix （M） protein gene-specific primers and compared with established conventional RT-PCR and TaqMan RT-PCR. The assay amplifies a 124 bp fragment of the PPRV M gene with Tm of 78.28 to 78.50. The assay was linear within a range of 50 ng to 0.5 fg total virus RNA with a detection limit （sensitivity） of 0.5 fg. Based on the serial dilution of the live-attenuated PPR vaccine virus, the detection limit was -0.0001 cell culture infectious dose 50% units （TCID50）. Additionally, swab materials spiked with known titre of vaccine virus were equally well detected in the assay. The standardized rt RT-PCR was easily employed for the detection of PPRV nucleic acid directly in the field and experimental clinical samples. The assay detected the PPRV nucleic acid as early as 3 day post infection （dpi） and up to 20 dpi in swab materials from the experimental samples. The assay was rapid and more sensitive than TaqMan and conventional RT-PCR in the detection of PPRV nucleic acid from the PPR suspected clinical samples of sheep and goats. Therefore, the established, simplified SYBR green rt RT-PCR is an alternative test to the already existing various diagnostic assays and could be useful for rapid clinical diagnosis with advantage in reducing risk of contamination.

Accurate method based on data filtering for quantitative multi-element analysis of soils using CF-LIBS

To obtain more stable spectral data for accurate quantitative analysis of multi-element,especially for the large-area in-situ elements detection of soils, we propose a method for a multielement quantitative analysis of soils using calibration-free laser-induced breakdown spectroscopy(CF-LIBS) based on data filtering. In this study, we analyze a standard soil sample doped with two heavy metal elements, Cu and Cd, with a specific focus on the line of Cu I324.75 nm for filtering the experimental data of multiple sample sets. Pre-and post-data filtering,the relative standard deviation for Cu decreased from 30% to 10%, The limits of detection(LOD)values for Cu and Cd decreased by 5% and 4%, respectively. Through CF-LIBS, a quantitative analysis was conducted to determine the relative content of elements in soils. Using Cu as a reference, the concentration of Cd was accurately calculated. The results show that post-data filtering, the average relative error of the Cd decreases from 11% to 5%, indicating the effectiveness of data filtering in improving the accuracy of quantitative analysis. Moreover, the content of Si, Fe and other elements can be accurately calculated using this method. To further correct the calculation, the results for Cd was used to provide a more precise calculation. This approach is of great importance for the large-area in-situ heavy metals and trace elements detection in soil, as well as for rapid and accurate quantitative analysis.

Research on batch multielement rapid quantitative analysis based on the standard curve-assisted calibration-free laserinduced breakdown spectroscopy method

This study proposes a batch rapid quantitative analysis method for multiple elements by combining the advantages of standard curve(SC)and calibration-free laser-induced breakdown spectroscopy(CF-LIBS)technology to achieve synchronous,rapid,and accurate measurement of elements in a large number of samples,namely,SC-assisted CF-LIBS.Al alloy standard samples,divided into calibration and test samples,were applied to validate the proposed method.SC was built based on the characteristic line of Pb and Cr in the calibration sample,and the contents of Pb and Cr in the test sample were calculated with relative errors of 6%and 4%,respectively.SC built using Cr with multiple characteristic lines yielded better calculation results.The relative contents of ten elements in the test sample were calculated using CF-LIBS.Subsequently,the SC-assisted CF-LIBS was executed,with the majority of the calculation relative errors falling within the range of 2%-5%.Finally,the Al and Na contents of the Al alloy were predicted.The results demonstrate that it effectively enables the rapid and accurate quantitative analysis of multiple elements after a single-element SC analysis of the tested samples.Furthermore,this quantitative analysis method was successfully applied to soil and Astragalus samples,realizing an accurate calculation of the contents of multiple elements.Thus,it is important to advance the LIBS quantitative analysis and its related applications.

Simplified quantitative analysis method and its application in the insitu synthesized copper-based azide chips

Copper-based azide(Cu(N_(3))2 or CuN_(3),CA)chips synthesized by in-situ azide reaction and utilized in miniaturized explosive systems has become a hot research topic in recent years.However,the advantages of in-situ synthesis method,including small size and low dosage,bring about difficulties in quantitative analysis and differences in ignition capabilities of CA chips.The aim of present work is to develop a simplified quantitative analysis method for accurate and safe analysis of components in CA chips to evaluate and investigate the corresponding ignition ability.In this work,Cu(N_(3))2 and CuN_(3)components in CA chips were separated through dissolution and distillation by utilizing the difference in solubility and corresponding content was obtained by measuring N_(3)-concentration through spectrophotometry.The spectrophotometry method was optimized by studying influencing factors and the recovery rate of different separation methods was studied,ensuring the accuracy and reproducibility of test results.The optimized method is linear in range from 1.0-25.0 mg/L,with a correlation coefficient R^(2)=0.9998,which meets the requirements of CA chips with a milligram-level content test.Compared with the existing ICP method,component analysis results of CA chips obtained by spectrophotometry are closer to real component content in samples and have satisfactory accuracy.Moreover,as its application in miniaturized explosive systems,the ignition ability of CA chips with different component contents for direct ink writing CL-20 and the corresponding mechanism was studied.This study provided a basis and idea for the design and performance evaluation of CA chips in miniaturized explosive systems.