Determination of 27 volatile organic compounds in exhaled breath by thermal desorption-gas chromatography-mass spectrometry / 环境与职业医学

Background Volatile organic compounds (VOCs) in exhaled breath are closely associated with respiratory diseases and are linked to various metabolic reactions in the human body. A quantitative analytical method can provide technical support for studying VOCs related to various diseases. Objective To establish a thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) method for the determination of 27 VOCs in exhaled breath. Methods VOCs in exhaled breath were collected using a Bio-VOC sampler and enriched with Tenax TA thermal desorption tubes before TD-GC-MS analysis. Standards were collected using thermal desorption tubes and optimized for thermal desorption conditions as well as chromatographic and mass spectrometric conditions: The separation of the 27 VOCs was achieved by an optimized temperature program, the improvement of sensitivity by optimizing quantitative ions, and the increase of VOCs desorption efficiency by optimizing thermal desorption time and temperature. Limit of detection, limit of quantification, accuracy, precision, and stability of the proposed method were investigated by spiking with a blank gas bag, and exhaled breath samples from 20 healthy individuals were collected for an application study of the proposed method. Results The thermal desorption temperature was 280 ℃, and desorption time was 6 min. A VF-624ms chromatographic column was selected for the separation of target substances. The initial temperature of heating program was 35 ℃, maintained for 1 min, and then increased to 100 ℃ at a heating rate of 3 ℃·min−1 for 1 min, followed by increasing to 210 ℃ at a heating rate of 28 ℃·min−1 for 5 min. A quantitative analysis was conducted with a single ion monitoring (SIM) mode. Under these conditions, the 27 VOCs showed good linear relationships in their respective concentration ranges and the correlation coefficients were higher than 0.9990. The limits of detection of the method were in the range of 0.01-0.13 nmol·mol−1, the limits of quantification were in the range of 0.02-0.44 nmol·mol−1, and the spiked recoveries were in the range of 80.1%-120.5%, with intra-batch and inter-batch precision ≤ 18.8% and 17.9% respectively. All substances can be stored at room temperature (23-28 °C) for 7 d and at 4 °C for 14 d. The proposed method was applied to exhaled breath samples from 20 subjects with detection rates≥ 80% (except for trans-2-pentene and decane) and a concentration range of 0.00-465.50 nmol·mol−1. Conclusion The established TD-GC-MS method for quantification of VOCs in exhaled breath is characterized by high sensitivity and good accuracy, and is suitable for quantitative determination of VOCs in exhaled breath, which can provide technical support for the study of exhaled breath VOCs.

Fusariosis en pacientes con cáncer: serie de 13 casos y revisión de la literatura / Fusariosis in cancer patients: 13 case series report and literature review

La fusariosis es una micosis oportunista producida por Fusarium spp. Su presentación clínica depende del estado inmunológico del huésped, especialmente, el de aquellos con enfermedades hematooncológicas, cuyas manifestaciones varían desde formas localizadas hasta infección fúngica invasora. El cultivo de piel o de sangre permite orientar el tratamiento antifúngico combinado con anfotericina B y voriconazol. Se presentan 13 casos de pacientes con cáncer en un periodo de once años que desarrollaron fusariosis diseminada; asimismo, se hizo con una revisión extensa de la literatura. En esta serie de casos, la mortalidad fue del 61,5 % (8/13), a pesar del uso del antifúngico. De los 13 pacientes, 11 tenían neoplasia hematológica y 2 neoplasia sólida. El factor de riesgo más importante fue la neutropenia profunda. El compromiso de la piel y los hemocultivos positivos facilitaron la prescripción del tratamiento combinado en la mayoría de los casos. La neutropenia febril persistente asociada a lesiones cutáneas, la onicomicosis, los nódulos o las masas pulmonares permitieron sospechar una infección fúngica invasora por Fusarium spp. El objetivo de la presentación de esta serie de casos es recordar el diagnóstico de fusariosis a la comunidad médica en contacto con pacientes oncológicos, con neutropenia febril profunda y persistentes.

The fusariosis is an opportunistic mycosis caused by Fusarium spp. Its clinical presentation depends on the immunological status of the host, especially in patients with hemato-oncological diseases, whose manifestations vary from localized to invasive fungal infections. Skin or blood culture helps to guide combined antifungal treatment with amphotericin B and voriconazole. Here, we present 13 cases in a period of eleven years of patients with cancer who developed disseminated fusariosis and their outcomes, together with a review of the related literature. In this series of cases, mortality was 61.5 % (8/13), despite the use of the antifungal. Out of the 13 cases, 11 had hematological neoplasia and 2 solid neoplasia. The most determinant risk factor was profound neutropenia. Skin involvement and positive blood cultures in most cases allowed combined treatment prescription. Persistent febrile neutropenia associated with skin lesions, onychomycosis, nodules, or lung masses lead to suspicion of Fusarium spp. fungal invasive infection. The aim of this series of cases is to remind healthcare professionals that oncological patients with deep and persistent febrile neutropenia can develop fusariosis.

Geotricosis: fungemia en paciente con leucemia linfoblástica aguda / Geotrichosis: fungemia in a patient with acute lymphoblastic leukemia

La fungemia por Geotrichum spp. es poco frecuente y altamente letal. En el Instituto Nacional de Cancerología de Bogotá solo se han reportado dos casos: uno entre el 2001 y el 2007, y el otro entre el 2012 y el 2018. Este tipo de infección es más común en pacientes con algún grado de compromiso del sistema inmunitario, por lo que puede presentarse en pacientes con neoplasias hematológicas malignas. Se presenta el caso de un hombre de 27 años con recaída de leucemia linfoblástica aguda, que ingresó con poliartralgias de cinco días de duración. También cursaba con neutropenia febril, celulitis sin abscesos y bacteriemia por Staphylococcus aureus resistente a la meticilina para lo cual recibió terapia con oxacilina y cefepime. Sin embargo, persistía la neutropenia febril por lo que se sospechó una infección fúngica invasora. Se tomó un nuevo set de hemocultivos y se inició tratamiento antifúngico. En los hemocultivos se identificaron artroconidias y mediante espectrometría de masas por láser de matriz asistida de ionización-desorción se confirmó la presencia de Geotrichum spp. Se ajustó el tratamiento antifúngico con deoxicolato de anfotericina B por 14 días y voriconazol por cuatro semanas. Luego de una estancia prolongada se le dio de alta. Aunque la incidencia de la fungemia por Geotrichum spp. es baja, en pacientes con neoplasias hematológicas malignas debe considerarse en el contexto de una neutropenia febril que es persistente a pesar del tratamiento antimicrobiano de amplio espectro. La identificación de los agentes causantes de fungemias con herramientas de proteómica, como la espectrometría de masas mencionada, permite ajustar el tratamiento dirigido y reducir las complicaciones, la estancia hospitalaria y la mortalidad.

Fungemia caused by Geotrichum spp. is rare and highly lethal. The Instituto Nacional de Cancerología in Bogotá reported just two cases: one in the period 2001-2007 and the other in 2012-2018. This type of infection is more common in any kind of immunocompromised patients, so it can occur in those with hematological malignancies. Here we present the case of a 27-year-old man, diagnosed with acute lymphoblastic leukemia in relapse and admitted with polyarthralgia for five days, febrile neutropenia, non- abscessed cellulitis, and bacteremia due to methicillin-sensitive Staphylococcus aureus. The patient received therapy with oxacillin and cefepime, but the febrile neutropenia persisted. A new set of blood cultures was taken, and antifungal treatment was started because of the suspicion of invasive fungal infection. Arthroconidia were identified in blood cultures and Geotrichum spp. was confirmed using matrix-assisted laser desorption-ionization mass spectrometry. The antifungal treatment was adjusted with amphotericin B deoxycholate for 14 days and voriconazole for four weeks, and after a prolonged stay, the patient was discharged. Although the incidence of fungemia caused by Geotrichum spp. is low, it must be considered in patients with hematological malignancies and persistent febrile neutropenia despite the broadspectrum antimicrobial treatment. The confirmation of fungemia causing agents, with proteomic tools such as the mentioned mass spectrometry, allows treatment adjustment and decreases complications, hospital stay, and mortality.

Determination of iodine in workplace air by inductively coupled plasma mass spectrometry / 中国职业医学

Objective To establish a solvent desorption inductively coupled plasma-mass spectrometry (ICP-MS) method for determination of iodine in workplace air. Methods Iodine in workplace air was collected with alkaline activated carbon tube and desorbed with 10.0 mL pure water or 20 mmol/L sodium bicarbonate solution. Rhenium-185 was used as an internal standard for quantification. The sample was determined in standard mode and kinetic energy discrimination collision (KED) mode by ICP-MS. Results In standard mode, iodine showed a good linear range in the concentration of 9.0 to 1 100.0 μg/L, with a correlation coefficient of 0.999 3 and a detection limit of 2.7 μg/L. In KED mode, iodine showed a good linear range in the concentration of 24.3 to 800.0 μg/L, with a correlation coefficient of 0.999 1 and a detection limit of 7.3 μg/L. The average desorption efficiency using pure water ranged from 99.1% to 106.7%, with within-run relative standard deviation (RSD) of 3.1% to 8.0% and between-run RSD of 4.9% to 9.3%. The average desorption efficiency using sodium bicarbonate solution ranged from 96.5% to 105.3%, with within-run RSD of 4.9% to 8.6% and between-run RSD of 2.5% to 9.9%. There were no statistical significant differences in the main effects of desorption solution, ICP-MS detection mode, their interaction on average desorption efficiency and within-run RSD (all P>0.05). Samples could be stored at room temperature for at least 7 days. Conclusion This method is highly sensitive, accurate, and suitable for the determination of iodine in workplace air. The sample pretreatment is simple and rapid.

Determination of two isomers of tetrachloroethane by solvent desorption-gas chromatography in workplace air / 中国职业医学

Objective: To establish a solvent desorption-gas chromatography method for the determination of 1,1,2,2-tetrachloroethane and 1,1,1,2-tetrachloroethane in workplace air. Methods: The 1,1,2,2-tetrachloroethane and 1,1,1,2-tetrachloroethane in workplace air were collected using activated carbon tubes, desorbed with carbon disulfide, and separated and detected by gas chromatography. The quantifications were based on standard curves. Results: The linear ranges of 1,1,2,2-tetrachloroethane and 1,1,1,2-tetrachloroethane were 0.98-395.50 and 0.87-395.50 mg/L, respectively, with the correlation coefficient of 0.999 95. The detection limits were 0.29 and 0.26 mg/L, respectively. The average of desorption efficiency was 92.04%-104.67%. The within- and between-run relative standard deviations were 1.42%-2.09% and 1.63%-6.09%, respectively. The sampling efficiency was more than 98.00%. The samples could be stored at room temperature for at least 14 days. Conclusion: This method can be used in detection of 1,1,2,2-tetrachloroethane and 1,1,1,2-tetrachloroethane in workplace air.

Determination of dimethyl carbonate in workplace air by solvent desorption-gas chromatography / 中国职业医学

Objective: To establish a solvent desorption-gas chromatography method for determination of dimethyl carbonate (DMC) in workplace air. Methods: The air samples were collected using activated carbon tubes, desorbed by carbon disulfide, separated by dimethylpolysiloxane capillary columns, and detected by a flame ionization detector. Results: The linear range of DMC was 2.14 to 1.07×104 mg/L, and the correlation coefficient was greater than 0.999. The detection limit was 0.14 mg/L, the lower limit of quantification was 0.47 mg/L, the minimum detection concentration was 0.10 mg/m3, and the minimum quantification concentration was 0.32 mg/m3 (based on 1.5 L workplace air). The average desorption efficiency of the method was 96.2% to 102.0%. Both the within-run and between-run relative standard deviations were 0.9% to 2.3%. The samples could be stored for at least seven days at four celsius degree. Conclusion: This method shows high desorption efficiency, high sensitivity, good precision and is simple in using. It can be used for the determination of DMC in workplace air.

Detection of common candidemia pathogens based on PCR combined with MALDI-TOF MS / 中华检验医学杂志

Objective:A high-throughput assay for the detection of five common clinical Candidaemia pathogens was established by combining polymerase chain reaction (PCR) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS).Method:Establishment of methodology. We selected Candida albicans, Candida parapsilosis, Candida glabrata, Candida krusei, Candida tropicalis to be the target pathogens and the internal transcribed spacer (ITS) region as the target gene. Specific single base extension primers were designed to perform single base extension reaction in the same reaction system. MALDI-TOF MS was used to detect the characteristic peaks of each target pathogen. The sensitivity and specificity of the detection system were verified by using spiked blood samples. Totally 108 blood samples from proven or suspected candidaemia patients were collected from October 2021 to September 2022 in a hospital in Beijing. The results of nucleic acid mass spectrometry were compared with those of clinical blood culture. Results:The established nucleic acid mass spectrometry detection system can simultaneously detect five common clinical Candida species. Each strain can produce specific product peaks and there is no mutual interference between the strains. The detection limit of Candida albicans was 100 CFU/ml. The detection limit of Candida parapsilosis, Candida glabrata, Candida krusei and Candida tropicalis was 10 CFU/ml. For the 108 blood samples, the sensitivity, specificity, positive predictive value and negative predictive value of nucleic acid mass spectrometry were 94.74% (36/38), 97.14% (68/70), 92.31% (36/39) and 98.55% (68/69), respectively. The McNemar χ 2 test showed no significant difference between the two methods ( P>0.05), and the Kappa consistency test showed good consistency between the two methods ( Kappa=0.9, P<0.05). Conclusion:A nucleic acid mass spectrometry detection system suitable for clinical candida detection was successfully constructed, and the method validation results were consistent with the clinical blood culture.

Diagnosis of periprosthetic joint infection based on semi-quantitative detection of synovial fluid calprotectin by MALDI-TOF MS / 中华检验医学杂志

Objective:To explore the clinical value of synovial fluid calprotectin for the diagnosis of periprosthetic joint infection (PJI).Methods:Based on prospective cohort study design, a total of 82 patients suspected of PJI after hip and knee arthroplasty in the First Medical Center of the PLA General Hospital from July 2021 to June 2022 were selected. Patients were divided into infection group (PJI, n=39) and non-infection group (non-PJI, n=43) according to the diagnostic criteria proposed by the Second International Consensus Conference in 2018. The matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was used for double-blind detection of calprotectin and internal reference standard (IRS) in synovial fluid of patients. The peaks of target protein and IRS were recorded for further analysis. Mann-Whitney U test was used to compare the concentrations of S100A8 and S100A9 between the two groups, and receiver operating characteristic curve (ROC) was used to analyze the diagnostic efficacy of S100A8 and S100A9 for PJI. Results:Calprotectin was detected as monomers S100A8 and S100A9. Synovial fluid S100A8 was significantly higher in the PJI group than that in the non-PJI group [1.57 (0.48, 4.17) vs 0.00 (0.00, 0.05), Z=?7.221, P<0.05]. Synovial fluid S100A9 was also significantly higher in the PJI group than that in the non-PJI group [0.74 (0.29, 1.70) vs 0.06 (0.00, 0.10), Z=?6.255, P<0.05]. When using S100A8 and S100A9 to diagnose PJI, the sensitivity were 97.4% and 87.2%, the specificity were 86.0% and 88.4%, and the area under the ROC were 0.964 (95% CI 0.929-0.998) and 0.902 (95% CI 0.924-0.996), respectively. Conclusion:The detection of synovial fluid S100A8 and S100A9 by MALDI-TOF MS can make a satisfactory diagnosis for PJI.

Exploration and advance of key techniques in MALDI mass spectrometry imaging / 药学学报

Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) is a new imaging technique with label-free, rapid, and high throughput features. It has bloomed in the analysis on the spatial distribution of biomolecules such as drugs, metabolites, peptides and proteins on the tissue surface in virtue of providing high data throughput from non-targeted full analysis and high accuracy from targeted analysis. The acquisition of MSI signal response with high sensitivity, high spatial resolution, and good stability is directly depended on the appropriate sample preparation approaches, and flexible and various data processing tools will help the non-target data mining to meet the demands of visualization, spatial distribution and multiple index applications so as to reveal the scientific rules beneath the data. This review briefly summarizes the key advances in MALDI-MSI from aspects of sample preparation procedures, data processing and visualization. It also illustrates the characteristics, difficulties and probable solutions derived from these key techniques.

A case of Aspergillus salwaensis-induced spinal infection / 中国热带医学

@#Abstract: To report a case of Aspergillus salwaensis-induced spinal infection and its laboratory detection. The inflammatory granulation and necrotic tissue samples of a patient with spinal infection were collected from, the Affiliated Hospital of Chengde Medical College on June 17, 2020 for direct smear microscopy and culture, and the isolated strain was identified by microscopy by smear staining, matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF-MS), molecular identification and in vitro antifungal susceptibility test. The patient was 62 years old female and presented with recurrent chest and back pain with no obvious cause. The initial diagnosis was spinal infection, after 7 days of treatment with levofloxacin, the effect was not good. Surgery was then performed remove the lesion via posterior thoracic debridement, and fungal hypha was observed under microscope in tissue specimens. The isolated strains had no typical structure, MALDI-TOF-MS was used for identification for many times, but there was no identification result. After 7 days of fluconazole treatment, the patient's condition improved, and her chest and back pain were alleviated compared to before surgery. The patient was discharged and followed up in the outpatient department, the fungus was later identified as Aspergillus salwaensis by sequence analysis of the internal transcribed spacer (ITS) gene sequencing, and the patient's antifungal medication was changed to voriconazole after with the attending physician. The patient consciously recovered well with no pain in the operative area and normal spinal activity at 1 year follow-up. The possibility of spinal fungal infection should be considered in patients with back pain without a clear cause and poor response to routine antibiotic treatment. Direct smear report of microscopic results are very important for guiding clinical antibiotic selection for rare filament fungi with atypical colony and microscopic morphology and unsuccessful MALDI-TOF-MS identification, molecular biological methods such as ITS sequence analysis can be helpful for early identification of the fungal species, improving identification speed.

A peculiar case of onychomycosis caused by Cladosporium halotolerans

ABSTRACT A 49-year-old patient with changes in the nails of the hallux for 10 years was diagnosed with onychomycosis. The identity of the causative agent was confirmed as Cladosporium halotolerans from the Cladosporium sphaerospermum species complex using molecular techniques. MALDI-TOF identified the agent as C. sphaerospermum complex species. Overall, species such as onychomycosis agents should attract special attention to avoid mistakes in the identification process while considering a probable contaminant as responsible for the disease. These species deserve attention since there are rare descriptions of them as causes of onychomycosis. It is important to recognize them as causes of disease and not just as a probable contaminant.

Significance of Aspergillus spp. isolation in defining cases of COVID-19 Associated Pulmonary Aspergillosis - CAPA

ABSTRACT COVID-19-Associated Pulmonary Aspergillosis (CAPA) is a relatively common complication in patients with severe forms of the disease caused by the SARS-CoV-2 virus. Diagnosing and confirming CAPA is challenging. In this study, Aspergillus spp. isolation in respiratory specimens from patients with COVID-19 was evaluated for identifying cases of CAPA. In 2020-2021, 17 Aspergillus spp. were isolated from 15 COVID-19 patients admitted to a university hospital in Brazil. Patient records were retrospectively reviewed to obtain clinical-epidemiological data and other markers of Aspergillus spp. infection and then compared with the ECMM/ISHAM criteria for defining CAPA. Probable CAPA was defined in 5/10 patients, who had Aspergillus spp. isolated from Bronchoalveolar Lavage (BAL) or a positive galactomannan blood test. Additionally, anti-Aspergillus antibodies were detected in two of these patients, during active or follow-up phases of CAPA. In another seven patients with Aspergillus spp. isolated from tracheobronchial aspirate or sputum, CAPA was presumed, mainly due to deterioration of clinical conditions and new lung imaging suggestive of fungal infection. Antifungal agents to control CAPA, particularly voriconazole, were used in 9/15 cases. In cases of probable CAPA and remaining patients, clinical conditions and comorbidities were similar, with lethality being high, at 60% and 71%, respectively. The number of CAPA cases defined by scientific criteria was lower than that assumed in the clinical context. This was largely due to the lack of BAL collection for fungal culture and the non-intensive use of other markers of invasive aspergillosis. The isolation of Aspergillus spp. in different respiratory specimens should alert clinicians to the diagnosis of CAPA.

Detection of Microorganisms in Clinical Sonicated Orthopedic Devices Using Conventional Culture and qPCR / Detecção de microrganismos em dispositivos ortopédicos sonicados clínicos usando cultura convencional e qPCR

Abstract Objective To evaluate the sensitivity and specificity of the quantitative real-time polymerase chain reaction (qPCR) for 16S rDNA gene screening using sonicated fluid from orthopedic implants. Methods A retrospective study was conducted on 73 sonicated fluids obtained from patients with infection associated with orthopedic implants. The samples were subjected to conventional culture and molecular testing using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and qPCR for 16S rDNA. The cycle threshold values were used to define a cut-off of the qPCR of the 16S rDNA for negative and positive cultures. Results No statistical differences were observed between the positive and negative culture groups based on the time from the first surgery to infection (p= 0.958), age (p =0.269), or general comorbidities. Nevertheless, a statistical difference was found between the mean duration of antibiotic use before device removal (3.41 versus 0.94; p =0.016). Bacterial DNA was identified in every sample from the sonicated fluids. The median cycle thresholds of the positive and negative cultures were of 25.6 and 27.3 respectively (p< 0.001). As a diagnostic tool, a cycle threshold cut-off of 26.89 demonstrated an area under the curve of the receiver operating characteristic of 0.877 (p≤ 0.001). Conclusion The presence of antimicrobial agents for more than 72 hours decreased culture positivity, but did not influence the qPCR results. Despite this, amplification of the 16S rDNA may overestimate infection diagnosis.

Resumo Objetivo Avaliar a sensibilidade e a especificidade da reação em cadeia de polimerase em tempo real quantitativa (quantitative real-time polymerase chain reaction, qPCR, em inglês) para a triagem do gene rDNA 16S, com a utilização do fluido sonicado de implantes ortopédicos. Métodos Um estudo retrospectivo foi realizado em 73 fluidos sonicados obtidos de pacientes com infecção associada aos implantes ortopédicos. As amostras foram submetidas a cultura convencional e a teste molecular utilizando ionização e dessorção a laser assistida por matriz com espectrometria de massa por tempo de voo (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, MALDI-TOF MS, em inglês) e qPCR para o gene rDNA 16S. Os valores limiares do ciclo foram usados para definir um ponto de corte para a qPCR do gene rDNA 16S para culturas negativas e positivas. Resultados Não foram observadas diferenças estatísticas entre os grupos de cultura positiva e negativa com base no tempo desde a primeira cirurgia até a infecção (p= 0,958), na idade (p= 0,269), ou nas comorbidades em geral. No entanto, uma diferença estatística foi encontrada entre a duração média do uso de antibióticos antes da remoção do dispositivo (3,41 versus 0,94; p= 0,016). O DNA bacteriano foi identificado em todas as amostras dos fluidos sonicados. Os limiares do ciclo médio de culturas positivas e negativas foram de 25,6 e 27,3, respectivamente (p< 0,001). Como uma ferramenta de diagnóstico, um corte do limite do ciclo de 26,89 demonstrou uma área sob a curva da característica de operação do receptor de 0,877 (p ≤ 0,001). Conclusão A presença de agentes antimicrobianos por mais de 72 horas diminuiu a positividade da cultura, mas não influenciou os resultados da qPCR. Apesar disso, a amplificação do rDNA 16S pode sobrestimar o diagnóstico de infecção.

Application and evaluation of matrix-assisted laser desorption ionization time-of-flight mass spectrometry in environmental pollution investigation of blood collection and supply institutions / 中国输血杂志

【Objective】 To investigate the environmental pollution of blood collection and supply institutions by using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and evaluate its application value. 【Methods】 Colonies of air from blood donation sites, skin puncture sites of blood donors, platelet storage boxes, platelet collection equipment, object surfaces of related experimental consumables and cuff surfaces of staff after disinfection were collected, and typical colonies after cultivation were selected for microbial identification by microbial mass spectrometry and then compared with bacteria results detected in blood components from May 2017 to May 2021. 【Results】 Aseptic growth, the number of colonies ≤4.0 CFU/ dish, and the number of colonies > 4.0 CFU/dish accounted for 21.20%, 62.20% and 16.60%, respectively. The qualified rate from high to low was platelet storage box, bacteria settling in the air of blood donation room after disinfection, platelet collection equipment, skin puncture site of blood donors after disinfection, the surface of platelet consumables and the surface of medical staff's overalls. After disinfection, the blood donors' skin puncture sites were compared with other collection sites, and the t values were 2.0371, 1.508, 2.109, 1.961 and 1.778, respectively, with no significant difference (P>0.05). Thirty cases of bacterial contamination of blood components were detected from May 2017 to May 2021, among which the detection rate of apheresis platelets was the highest, and the t values were 1.731 and 2.272, relative to the contamination frequency of erythrocytes and plasma bacteria (P>0.05), while the t value was 2.875, relative to concentrated platelets, with significant difference (P<0.05). 【Conclusion】 Bacterial contamination of blood components mostly come from air bacteria settling, blood donors' arms and skin after disinfection, and surfaces of related equipment and materials. Therefore, it is of clinical significance to conduct strict disinfection of working sites, establish disinfection monitoring methods and formulate disinfection hygiene standards in blood stations.

Application of MALDI-TOF MS in clinical difficult blood group typing / 中国输血杂志

【Objective】 To explore the application of matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) in the genotyping of difficult blood typing samples, and to provide evidence for clinical blood transfusion. 【Methods】 Three ambiguous blood group samples, submitted to Shanghai Blood Center by Shanghai regional hospitals, were studied, of which Sample1 included the proband and his parents. Serological methods were used to perform blood group typing, direct antibody test, unexpected antibody screening and identification test. Blood group genotyping was performed by using the MALDI-TOF MS detection systeme stablished in our laboratory. Sanger sequencing was used to confirm gene mutation sites, and serological or flow methods were used to verify specific samples′ phenotype. 【Results】 Serological results indicated the existence of antibodies against high frequency antigens in sample 1 (including proband and her mother), 2 and 3. The genotyping results of MALDI-TOF MS showed that the proband of sample 1 was Di(a+ b+ ), her father was Di(a-b+ ), her mother was Di(a+ b-), sample 2 was p, and sample 3 was Jr(a-). Sequencing results of three samples were consistent with mass spectrometry typing results. Serological results showed that sample 2 had a p phenotype. The flow cytometry results suggested that sample 3 had a Jr(a-) phenotype. 【Conclusion】 For the first time, we applied MALDI-TOF MS technology to blood type genotyping of ambiguous clinical samples in China. Compared with other genotyping methods such as PCR-SSP, MALDI-TOF MS has the advantages of rapid detection, high throughput and high specificity, which would contribute to identification of difficult blood typing samples in the future, as well as rare blood group screening.

Application of Matrix-assisted Laser Desorption Ionization Mass Spectrometry in Analysis of Traditional Chinese Medicine：A Comprehensive Review / 中国实验方剂学杂志

Traditional Chinese medicine （TCM）， which owns abundant chemical components and complex action pathways， has been widely recognized in the prevention and treatment of diseases. Some analysis methods have been emerged in order to ensure the quality of TCM and to develop new TCM drugs. Matrix-assisted laser desorption ionization mass spectrometry （MALDI-MS） is a soft ionization mass spectrometric technique with the advantages of high throughput， high sensitivity， low cost and so on. It provides technical support for the molecular level study on TCM. At present， this technique has been used in the field of composition analysis and metabonomics research of TCM， and plays an important role in the identification of Chinese herbal medicines， real-time molecular screening and the construction of metabolic network pathway of active ingredients. Among them， the selection of appropriate matrix and sample preparation technology is the key to ensure the detection effect of MALDI-MS. With the development and optimization of new matrix， the continuous improvement of sample preparation technology and the combination of MALDI-MS with various analytical methods will greatly improve the detection effect. Based on this， this paper discusses the application of MALDI-MS in TCM， including high-throughput detection of active ingredients in TCM， monitoring of the original medicines and their metabolites in vivo， and in situ visualization and characterization of tissue distribution information of active ingredients in TCM. It also discusses the application prospect and existing problems of MALDI-MS in TCM， so as to provide technical support for the identification of active ingredients in TCM， drug utilization and metabolism.

Establishment of a direct detection method for serum M-proteins without antibody enrichment based on MALDI-TOF MS technology / 中华检验医学杂志

Objective:To establish a matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) method for the direct detection of serum M protein without antibody enrichment, and to assess its detection performance.Methods:Method establishment. A total of 712 waste serum samples were collected from patients who applied for the M protein identification test in Beijing Chaoyang Hospital affiliated to Capital Medical University. The immunoglobulin light chain was obtained by reduction of IgG and IgA by TCEP, and the detection method was preliminarily determined. The waste serum samples from 20 healthy people were collected to determine the range of mass-to-charge ratios of κ and λ light chain ions. 8 parallel tubes and 8 batches were set up for intra-and inter-batch reproducibility evaluation. 10-fold, 100-fold and 200-fold diluted M protein from 23 positive samples were detected by established MALDI-TOF MS method, and its sensitivity was evaluated. 3 methods of IFE, SPE and MALDI-TOF MS were used to detect M protein simultaneously, and the coincidence rate between MALDI-TOF MS and IFE and SPE was calculated.Results:The repeatability within and between batches was 100%, respectively. The original, 10-, 100-and 200-fold dilutions of 23 M protein-positive samples were determined, and the detection limit of MALDI-TOF MS for M protein was 0.06-0.18 g/L. IFE as the gold standard, the overall coincidence rates of SPE and MALDI-TOF MS were 85.9% and 92.3%, respectively, and the positive coincidence rates of SPE and MALDI-TOF MS were 72.8% and 99.7%, respectively, of the 712 samples. Among the different types of M-proteins, MALDI-TOF-MS agreed 100% with IFE M-protein results for IgA, IgD, IgM, free light chain type and biclonal group, while the agreements of SPE for IgM, IgA and free light chain samples were only 66.7%, 58% and 19.5%, respectively. One positive sample in the IgG group was not detected by MALDI-TOF MS. 23 M-proteins positive samples were diluted by original, 10, 100 and 200 times to access the sensitivity of MALDI-TOF MS method. The coincidence rate of MALDI-TOF MS was 100% and IFE was 96% at 10-fold dilution. The coincidence rate of IFE was 28% and 23% of MALDI-TOF MS at 100-fold and 200-fold dilution, respectively.Conclusions:A MALDI-TOF MS method for the detection of serum M-proteins was successfully established. This method has the advantages of high detection throughput, fast speed, good sensitivity, specificity and coincidence rate.

Determination of eight volatile halogenated hydrocarbons in drinking water by headspace thermal desorption⁃gas mass spectrometry / 上海预防医学

ObjectiveTo establish a method for the determination of 8 volatile halogenated hydrocarbons in drinking water， including vinyl chloride， trichloroethylene， tetrachloroethylene， tetrachloromethane， chloroform， dichlorobromomethane， dichlorodibromomethane， and tribromomethane by headspace thermal desorption-gas mass spectrometry. MethodsThe water sample was kept in the headspace bottle at 60 ℃ for 40 min， and the volatile matter was transferred to the cold trap，subjected to thermal desorption， then analyzed by gas chromatography-mass spectrometry. ResultsThe linear ranges were 0.2‒20.0 μg·L-1 for vinyl chloride， 0.1‒20.0 μg·L-1 for chloroform， 0.02‒20.00 μg·L-1 for tetrachloromethane， 0.2‒20.0 μg·L-1 for trichloroethylene， 0.3‒20.0 μg·L-1 for dichlorobromomethane， 0.1‒20.0 μg·L-1 for tetrachloroethylene， 0.4‒20.0 μg·L-1 for dichlorodibromomethane， and 1.0‒20.0 μg·L-1 for tribromomethane. All the correlation coefficients were more than 0.997. The respective quantitative limits were 0.162， 0.073， 0.016， 0.184， 0.270， 0.071， 0.356 and 0.813 μg·L-1， and the respective recoveries were 98.0%‒101.0%， 102.0%‒110.0%， 99.2%‒101.0%， 95.5%‒96.2%， 96.0%‒102.0%， 100.0%‒102.0%， 99.0%‒105.0%， and 94.0%‒103.0%. ConclusionThe method is simple， sensitive， rapid， accurate and reliable， so it is applicable for the determination of 8 kinds of volatile halogenated hydrocarbons in drinking water.

The method of determination for butyronitrile and isobutyronitrile in the air of workplace by dissolved desorption-gas chromatography / 中华劳动卫生职业病杂志

Objective: To establish a method for the determination of butyronitrile and isobutyronitrile in the air of workplace by gas chromatography. Methods: In March 2020, butyronitrile and isobutyronitrile in the air of workplace was collected by silica gel, eluted with methanol, separated and determined by gas chromatogram with flame ionization detector, the characteristics of determination of nitrile and isobutyronitrile by gas chromatography were analyzed. Results: The limit of detection for butyronitrile and isobutyronitrile was 0.33 μg/ml. The linear range of butyronitrile determined by this method was 1.60-1600.00 μg/ml, y=2.295x-3.480, and the coefficient correlation was 0.99998, and the minimum detection concentration was 0.22 mg/m(3) (collected sample volume was 1.50 L) . The within-run precisions were 2.43%-4.12%, the between-run precisions were 1.72%-3.70%, and the desorption rates were 93.26%-98.41%. The linear range of isobutyronitrile determined by this method was 1.52-1520.00 μg/ml, y=2.208x-0.102, and the coefficient correlation was 0.99998, and the minimum detection concentration was 0.22 mg/m(3) (collected sample volume was 1.50 L) . The within-run precisions were 2.52%-3.22%, the between-run precisions were 1.20%-3.82%, and the desorption rates were 96.85%-102.50%. The sealed samples could be stored at least 10 days at room temperature without significant loss. Conclusion: The method has the advantages of good precision, high sensitivity and simple operation. It is suitable for the simultaneous determination of butyronitrile and isobutyronitrile in the air of workplace.

Spatial distribution characteristics of metabolities in rhizome of Paris polyphylla var. yunnanensis: based on MALDI-MSI / 中国中药杂志

In this study, a method was established for in-situ visualization of metabolite distribution in the rhizome of Paris polyphylla var. yunnanensis. To be specific, through matrix-assisted laser desorption/ionization-mass spectrometry imaging(MALDI-MSI), the spatial locations of steroidal saponins, amino acids, organic acids, phytosterols, phytoecdysones, nucleosides, and esters in rhizome of the medicinal plant were directly analyzed, and six unknown compounds with differential distribution in rhizome tissues were identified. The specific procedure is as follows: preparation of rhizome tissue section, matrix screening and optimization, and MALDI-MSI analysis. The results showed that the steroidal saponins were mainly distributed in the central, amino acids in epidermis and cortex, low-molecular-weight organic acids in central epidermis, phytosterols in the epidermis and lateral cortex, the phytoecdysones in epidermis and cortex, nucleosides(uneven distribution) in epidermis and cortex, growth hormones around the epidermis and cortex, particularly outside the cortex, and esters in cortex with unobvious difference among different tissues. In this study, the spatial distribution of meta-bolites in the rhizome of P. polyphylla var. yunnanensis was characterized for the first time. The result can serve as a reference for identifying and extracting endogenous metabolites of P. polyphylla var. yunnanensis, exploring the synthesis and metabolism mechanisms of the metabolites, and evaluating the quality of medicinal materials.