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PurposeThe Gartland extension-type supracondylar humerus (SCH) fracture is the most common paediatric elbow fracture. Treatment options range from nonoperative treatment (taping or casting) to operative treatments (closed reduction and percutaneous pinning or open reduction). Classification variability between surgeons is a potential contributing factor to existing controversy over treatment options for type II SCH fractures. This study investigated levels of agreement in extension-type SCH fracture classification using the modified Gartland classification system.MethodsA retrospective review was conducted on 60 patients aged between two and 12 years who had sustained an extension-type SCH fracture and received operative or nonoperative treatment at a tertiary children's hospital. Baseline radiographs were provided, and surgeons were asked to classify the fractures as type I, IIA, IIB or III according to the modified Gartland classification. Respondents were then asked to complete a second round of classifications using reshuffled radiographs. Weighted kappa values were calculated to assess interobserver and intraobserver levels of agreement.ResultsIn all, 21 paediatric orthopaedic surgeons responded to the survey and 15 completed a second round of ratings. Interobserver agreement for classification based on the Gartland criteria between surgeons was substantial with a kappa of 0.679 (95% confidence interval (CI) 0.501 to 0.873). Intraobserver agreement was substantial with a kappa of 0.796, (95% CI 0.628 to 0.864).ConclusionRadiographic classification of extension-type SCH fractures demonstrated substantial agreement both between and within surgeon raters. Therefore, classification variability may not be a major contributing factor to the treatment controversy for type II SCH fractures and treatment variability may be due to differences in surgeon preferences.Level of evidenceIII.

The biuret method is currently recognized as a reference measurement procedure for serum/plasma total protein by the Joint Committee for Traceability in Laboratory Medicine (JCTLM). However, as the reaction involved in this method is highly time-dependent, to ensure identical measurement conditions for calibrator and samples for high accuracy, a fast and simple measurement procedure is critical to ensure the precision and trueness of this method. We measured serum/plasma total protein using a Cary 60 spectrophotometer coupled with a fiber optic probe, which was faster and simpler than the conventional cuvette method. The biuret method utilizing alkaline solutions of copper sulfate and potassium sodium tartrate was added to the sample and calibrator (NIST SRM 927e) incubated for 1 h before measurement. A panel of samples consisting of pooled human serum, single donor serum, and certified reference materials (CRMs) from three sources were measured for method validation. Sixteen native patient samples were measured using the newly developed biuret method and compared against clinical analyzers. Additionally, the results of three cycles of a local External Quality Assessment (EQA) Programme submitted by participating clinical laboratories were compared against the biuret method. Our biuret method using fiber optic probe demonstrated good precision with within-day relative standard deviation (RSD) of 0.04 to 0.23% and between-day RSD of 0.58%. The deviations between the obtained values and the certified values for all three CRMs ranged from -0.38 to 1.60%, indicating good method trueness. The routine methods using clinical analyzers were also found to agree well with the developed biuret method using fiber optic probe for EQA samples and native patient samples. The biuret method using a fiber optic probe represented a convenient and reliable way of measuring serum total protein. It also demonstrated excellent precision and trueness using CRMs and patient samples, which made the method a simpler candidate reference method for serum protein measurement., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)

Background: Urine albumin (UA) is an important biomarker of chronic kidney disease. Current in vitro diagnostic medical devices (IVD-MDs) for measuring UA are not standardized, and median results among IVD-MDs differ by approximately 45%. Since fixed decision values are used to interpret UA, higher-order reference measurement procedures (RMPs) are needed for metrological traceability. Three candidate liquid chromatography-tandem mass spectrometry RMPs have been developed for UA., Methods: Eight single-donation human urine samples were measured by 3 candidate RMPs. Results were compared using t-test and variance component analysis., Results: The mean results for each urine sample from each RMP laboratory were not statistically different from the overall mean value by t-test. The median total CV including contributions from bias and imprecision among the 3 RMP laboratories was 6.23% using variance component analysis for each sample. The allowable bias to the RMP for an end-user IVD-MD was ≦9.0% or ≦3.0% based on the desirable or optimal total allowable error of 30% or 24%, respectively. A maximum allowable standard uncertainty for an RMP result was determined to be 4.3% or 3.3% for desirable or optimal performance, respectively. The standard uncertainties for all of the RMP laboratories meet the desirable and optimal standard uncertainty specifications., Conclusion: The candidate RMPs for UA in these 3 laboratories have suitable agreement of results and uncertainties for use as higher-order RMPs in the metrological traceability of end-user IVD-MDs for measuring UA., (© Association for Diagnostics & Laboratory Medicine 2024. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Self-administered pre-participation screening for physical activity (PA) requires an instrument that should be easily used and identify individuals at high risk. The Physical Activity Readiness Questionnaire (PAR-Q+) has been used for many years. Its ease of use and ability to identify those not fit to undergo PA has not been assessed. This study was to determine the rates of the PAR-Q+ in identifying adults who may not be fit for moderate or intense PA and obtain feedback on the use of this tool. A randomized, cross-sectional study involving a wide spectrum of members of the public was carried out. Participants were asked to provide their bio-characteristics, complete the PARQ+, and provide feedback on the questionnaire. With 1019 participants, about 33.1% of the participants using the PARQ+ would have required further medical evaluation. Except for those patients with respiratory illness, there was no difference in levels of PA in those who answered yes or no to the seven PARQ+ questions. Only 4 of the 7 main PAR-Q+ questions were perceived by the public as easily understood. Difficulties were encountered with 21 of the 45 follow-up questions, especially amongst those with co-morbidities. The wordiness of the questions and the large number of technical terms were also sources of concern. Suggestions were provided by participants on areas where improvements may be made to the wording of the questions. The study suggests that the PAR-Q+ probably over-identified those who require further medical evaluation. In addition, the wordiness of the questions and frequent use of medical jargon made the PARQ+ challenging to understand and use. The suggestions provide opportunities to review areas for possible improvements.

Background: Cognitive frailty, defined as having both physical frailty and cognitive impairment that does not satisfy the criteria for Major Neurocognitive Disorder, represents an elevated risk for morbidity. Hence, it is crucial to mitigate such risks. Physical activity interventions have been found effective in protecting against physical frailty and cognitive deterioration. This pilot RCT examines if smartwatches and mobile phone applications can help to increase physical activity, thereby improving physical and cognitive outcomes., Methods: Older individuals (n = 60) aged 60 to 85 years old will have their physical activity tracked using a smartwatch. The subjects will be randomized into two arms: one group will receive daily notification prompts if they did not reach the recommended levels of PA; the control group will not receive prompts. Outcome variables of physical activity level, neurocognitive scores, and physical frailty scores will be measured at baseline, T1 (3 months), and T2 (6 months). Sleep quality, levels of motivation, anxiety, and depression will be controlled for in our analyses. We hypothesize that the intervention group will have higher levels of physical activity resulting in improved cognitive and physical outcomes at follow-up. This study was approved by the National University of Singapore's Institutional Review Board on 17 August 2020 (NUS-IRB Ref. No.: H-20-038)., Discussion: Wearable sensors technology could prove useful by facilitating self-management in physical activity interventions. The findings of this study can justify the use of technology in physical activity as a preventive measure against cognitive frailty in older adults. This intervention also complements the rapidly rising use of technology, such as smartphones and wearable health devices, in our lives today., Registration Details: This study has been retrospectively registered on clinicaltrials.gov on 5th January 2021 (NCT Identifier: NCT04692974), after the first participant was recruited., Competing Interests: The authors declare that they have no competing interests., (Copyright: © 2024 Kiah Hui Siew et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Objectives: Low-density lipoprotein cholesterol (LDLC) is the primary cholesterol target for the diagnosis and treatment of cardiovascular disease (CVD). Although beta-quantitation (BQ) is the gold standard to determine LDLC levels accurately, many clinical laboratories apply the Friedewald equation to calculate LDLC. As LDLC is an important risk factor for CVD, we evaluated the accuracy of Friedewald and alternative equations (Martin/Hopkins and Sampson) for LDLC., Methods: We calculated LDLC based on three equations (Friedewald, Martin/Hopkins and Sampson) using the total cholesterol (TC), triglycerides (TG), and high-density lipoprotein cholesterol (HDLC) in commutable serum samples measured by clinical laboratories participating in the Health Sciences Authority (HSA) external quality assessment (EQA) programme over a 5 years period (number of datasets, n=345). LDLC calculated from the equations were comparatively evaluated against the reference values, determined from BQ-isotope dilution mass spectrometry (IDMS) with traceability to the International System of Units (SI)., Results: Among the three equations, Martin/Hopkins equation derived LDLC had the best linearity against direct measured (y=1.141x - 14.403; R 2 =0.8626) and traceable LDLC (y=1.1692x - 22.137; R 2 =0.9638). Martin/Hopkins equation (R 2 =0.9638) had the strongest R 2 in association with traceable LDLC compared with the Friedewald (R 2 =0.9262) and Sampson (R 2 =0.9447) equation. The discordance with traceable LDLC was the lowest in Martin/Hopkins (median=-0.725%, IQR=6.914%) as compared to Friedewald (median=-4.094%, IQR=10.305%) and Sampson equation (median=-1.389%, IQR=9.972%). Martin/Hopkins was found to result in the lowest number of misclassifications, whereas Friedewald had the most numbers of misclassification. Samples with high TG, low HDLC and high LDLC had no misclassification by Martin/Hopkins equation, but Friedewald equation resulted in ∼50% misclassification in these samples., Conclusions: The Martin/Hopkins equation was found to achieve better agreement with the LDLC reference values as compared to Friedewald and Sampson equations, especially in samples with high TG and low HDLC. Martin/Hopkins derived LDLC also enabled a more accurate classification of LDLC levels., (© 2023 Walter de Gruyter GmbH, Berlin/Boston.)

Urine albumin concentration and albumin-creatinine ratio are important for the screening of early-stage kidney damage. Commutable urine certified reference materials (CRMs) for albumin and creatinine are necessary for standardization of urine albumin and accurate measurement of albumin-urine ratio. Two urine CRMs for albumin and creatinine with certified values determined using higher-order reference measurement procedures were evaluated for their commutability on five brands/models of clinical analyzers where different reagent kits were used, including Roche Cobas c702, Roche Cobas c311, Siemens Atellica CH, Beckman Coulter AU5800, and Abbott Architect c16000. The commutability study was conducted by measuring at least 26 authentic patient urine samples and the human urine CRMs using both reference measurement procedures and the routine methods. Both the linear regression model suggested by the Clinical and Laboratory Standard Institute (CLSI) guidelines and log-transformed model recommended by the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) Commutability Working Group were used to evaluate the commutability of the human urine CRMs. The commutability of the human urine CRMs was found to be generally satisfactory on all five clinical analyzers for both albumin and creatinine, suggesting that they are suitable to be used routinely by clinical laboratories as quality control or for method validation of urine albumin and creatinine measurements., (© 2022. Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: This study aimed to explore how deployed healthcare workers (HCWs) perceived personal preparedness for response and their main avenues for coping to maintain resilience during the prolonged COVID-19 (SARS-CoV-2) pandemic., Methods: Semi-structured interviews were conducted with 25 HCWs deployed to the frontline for an extended period to provide acute COVID-19 related care. Interviews were audio-recorded, transcribed verbatim and analyzed thematically., Results: HCWs demonstrated heightened self-confidence and readiness to deal with public health emergencies owing to the ramped-up efforts in infrastructure for outbreak management and pre-emptive infectious disease training. Despite overall confidence, deployed HCWs had to adopt various coping mechanisms to sustain resilience during the prolonged pandemic. Main themes on coping centred around the value of team leaders and support from family members as an effective buffer for work-induced stress while institution-based counseling services and welfare were viewed as important for fostering internal locus of control and wellbeing., Conclusion: Our findings suggest that strategies such as on-the-job training, continuous education and improved communication would be essential to maintain resilience of deployed HCWs. Considerations should be also given to the swift implementation of blended wellness support comprising digital and in-person counseling to sustain wellbeing and prepare for endemic COVID-19.

Background: A chloride test is an integral part of a basic metabolic panel that is essential for the assessment of a patient's acid-base and electrolyte status. While many methods are available commercially for the routine measurement of chloride, there is a need to address the accuracy and variability among the measurement results, especially with the prevalence of patients seeking treatment across different healthcare providers for alternative opinions., Method: A method based on sector field inductively coupled plasma isotope dilution mass spectrometry (SF-ICP-IDMS) was developed for the measurement of chloride in human serum. The SF-ICP-IDMS method was then used to assign the target values in the Health Sciences Authority (HSA) External Quality Assessment (EQA) Programme to evaluate the results of chloride test from participating clinical laboratories., Results: The accuracy of the measurements was evaluated by comparing the results with the certified values of Electrolytes in Frozen Human Serum Certified Reference Materials (SRM 956c and SRM 956d) from the National Institute of Standards and Technology (NIST) at different chloride concentration levels. Over a five-year period from 2014-2018, the number of clinical laboratories which participated in the EQA Programme increased from 23 to 33. Comparison of robust means from the laboratories' results with our assigned target values revealed a reduction in relative deviation over time. The relationship between the deviation of each brand of clinical analysers and the chloride levels was established, where a larger deviation was uncovered at low chloride concentration. The SF-ICP-IDMS method was further demonstrated to be comparable with methods used by other metrology institutes in an international comparison organised by HSA under the auspice of the Consultative Committee for Amount of Substance - Metrology in Chemistry and Biology (CCQM)., Conclusion: The use of metrologically traceable assigned target values enabled the study of method biasness from a small pool of dataset in each of the four brands of clinical analysers in HSA EQA Programme. This work underscores the need to improve the accuracy of chloride measurements by regular participation in an accuracy-based EQA Programme., (Copyright © 2021 Elsevier GmbH. All rights reserved.)

Background: Frontline health care workers are experiencing a myriad of physical and psychosocial challenges amid the COVID-19 pandemic. There is growing recognition that digital technologies have the potential to improve the well-being of frontline workers. However, there has been limited development of wellness interventions using mobile health (mHealth) technology. More importantly, little research has been conducted on how frontline workers perceive mHealth-based support to promote their well-being., Objective: This study aimed to explore frontline workers' experience of conventional psychological wellness programs and their perceptions of the usefulness of mHealth apps and features for promoting well-being. It also sought to identify factors that could potentially influence uptake and retention of an mHealth-based wellness program., Methods: We conducted semistructured interviews using purposive sampling with frontline workers involved in the COVID-19 response. Various visual materials, collated from existing mHealth app features, were presented to facilitate discussion. Interviews were audio-recorded and transcribed verbatim. Thematic analysis based on grounded theory was undertaken. Themes were subsequently mapped to key nudge strategies-those commonly used for mHealth development-to assess participants' preferences for particular features and their reasoning., Results: A total of 42 frontline workers participated in 12 one-on-one interviews or focus group discussions. Frontline workers generally had a limited ability to identify their own psychological problems and liked the reminders functionality of the app to track their mood over time. A personalized goal-setting feature (ie, tailoring) and in-app resources were generally valued, while frequent coaching and messages (ie, framing) were seen as a distraction. The majority of participants desired a built-in chat function with a counselor (ie, guidance) for reasons of accessibility and protection of privacy. Very few participants appreciated a gamification function. Frontline workers commonly reported the need for ongoing social support and desired access to an in-app peer support community (ie, social influence). There were, however, concerns regarding potential risks from virtual peer interactions. Intrinsic motivational factors, mHealth app technicality, and tangible rewards were identified as critical for uptake and retention., Conclusions: Our study highlights the potential of mHealth apps with relevant features to be used as wellness tools by frontline health care workers. Future work should focus on developing a nonintrusive and personalized mHealth app with in-app counseling, peer support to improve well-being, and tangible and extrinsic rewards to foster continued use., (©Sungwon Yoon, Hendra Goh, Gayathri Devi Nadarajan, Sharon Sung, Irene Teo, Jungup Lee, Marcus E H Ong, Nicholas Graves, Tess Lin Teo. Originally published in the Journal of Medical Internet Research (https://www.jmir.org), 31.05.2021.)

Purpose: This study examined levels of agreement between paediatric orthopaedic surgeons in the need for operative management of extension-type supracondylar humerus fractures., Methods: This was the second phase of a two-part study. De-identified baseline anteroposterior and lateral elbow radiographs from 60 paediatric patients with extension-type supracondylar humerus fractures were compiled. After classifying each fracture according to Gartland classification guidelines, radiographs were randomized, and surgeons indicated whether they would use operative or non-operative management to treat each fracture. Kappa statistics using pairwise comparisons were calculated to determine agreement levels., Results: In total, 11 international surgeons participated, and 10/11 completed both survey rounds. The overall weighted interobserver agreement was moderate (0.530, 95%CI [0.215,0.854]) while overall weighted intraobserver agreement was substantial (0.740, 95%CI [0.513,0.963]). The largest variability in preferred treatment methods between surgeons was observed for type IIA fractures, with 6/11 preferring non-operative and 5/11 preferring operative management. The largest individual surgeon variability was observed for type IIA fractures, with 8/11 showing variability (defined by not having made the same decision for at least 90% of the cases) in choosing whether to operate., Conclusions: Our findings suggest moderate interobserver, and substantial intraobserver agreement in treatment decision making. The largest disagreements between surgeons were observed for type IIA and IIB fractures and treatment decisions did not follow expected trends based on surgeons' preferred treatment methods for each fracture type. This suggests differences in treatment approaches between surgeons in the management of type IIA fractures and highlights the role of other variables that underlie differences between surgeons' treatment preferences., Level of Evidence: III., (Copyright © 2020, The author(s).)

A systematic procedure for the determination of purity values of amino acid reference materials was developed by use of mass balance method where four categories of impurities (related structure impurities (RSIs), water, organic solvent residue (OSR), and non-volatile residue (NVR)) were quantified separately. The amount of RSIs was determined using a combination of three quantification methods. To ensure metrological traceability in the determination of RSIs, at least one such impurity in each candidate amino acid reference material was quantified using liquid chromatography-isotope dilution tandem mass spectrometry (LC-IDMS/MS). Other RSIs were determined using external calibration liquid chromatography-tandem mass spectrometry (LC-MS/MS) or o-phthaldialdehyde (OPA) derivatization, followed by liquid chromatography-ultraviolet (LC-UV) measurement. As the UV absorption of most RSIs came basically from the same chromophore after OPA derivatization, a relative peak area approach was used in the LC-UV method to quantify the amount of RSIs by comparing their peak areas with that of a reference RSI. The reference RSI was pre-selected and the amount determined by LC-IDMS/MS separately. The absence of D-amino acids was confirmed using Marfey's reagent derivatization, followed by LC-UV analysis. The amounts of water, OSR, and NVR were measured using Karl Fischer coulometry, gas chromatography-mass spectrometry (GC-MS) and thermogravimetry, respectively. By using this procedure, four amino acid (L-valine, L-leucine, L-isoleucine, and L-phenylalanine) certified reference materials (CRMs) were developed from the candidate materials. The homogeneity and stability of the CRMs were demonstrated by use of LC-IDMS/MS or OPA-LC-UV method, following the principles in ISO 17034 and ISO Guide 35.Graphical abstract.

Objectives: Urine albumin is measured in clinical laboratories by immunoturbidimetry. However, large biases are observed among the different routine methods. To standardize the measurement of urine albumin, a reference measurement procedure (RMP) and urine albumin certified reference materials (CRMs) are needed., Methods: A candidate RMP for urine albumin based on liquid chromatography-isotope dilution tandem mass spectrometry (LC-IDMS/MS) using human serum albumin as calibration standard was developed. Isotope-labeled human albumin was used as internal standard. Urine samples were digested using trypsin and eight resulting "signature" peptides of albumin were quantified by LC-IDMS/MS. The candidate RMP was employed in value assignment of external quality assessment (EQA) samples and certification of urine albumin reference materials. The commutability of the developed CRMs was assessed against patient samples., Results: The candidate RMP (recovery 101.5-103.2% and CV 1.2-3.3% at about 7-40 mg/L) met optimal performance goal. The lower limit of quantification was 0.03 mg/L as determined by signal-to-noise method. The EQA results from clinical laboratories using different immunoturbidimetric methods were generally comparable with assigned target values determined by the candidate RMP, with albumin concentrations ranging from 5 to 226 mg/L. Urine albumin reference materials (two levels) certified using the candidate RMP showed good commutability in a preliminary study., Conclusions: With optimal method precision and trueness, as well as comparability with routine methods, the developed RMP may be used for value assignment of EQA samples or certification of reference materials, which are important pillars in urine albumin method standardization., (© 2020 Walter de Gruyter GmbH, Berlin/Boston.)

The coronavirus disease 2019 (COVID-19) pandemic has placed large stressors on emergency departments (EDs) worldwide. As the pandemic progressed, EDs faced changing patient epidemiology and numbers. Our ED needed to rapidly transform to deal with the risk of COVID-19. Having limited floor space, we opted for a phased, dynamic response that allowed us to adapt the ED multiple times as the epidemiology of the pandemic evolved. The principles behind our response include guiding ED operations with data, enhancing infection control practices, and being prepared to transform areas of the ED to care for different groups of patients. Our experience can serve to guide other EDs in planning their response to surge capacity and ED operations during such pandemics., Competing Interests: The authors declare no conflicts of interest, (© 2020 The Authors. JACEP Open published by Wiley Periodicals LLC on behalf of the American College of Emergency Physicians.)

Over two decades, the Organic Analysis Working Group (OAWG) of the Consultative Committee for Amount of Substance: Metrology in Chemistry and Biology (CCQM) has organized a number of comparisons for clinically relevant small molecule organic biomarkers. The aim of the OAWG community is to be part of the coordinated international movement towards accuracy and comparability of clinical measurements that will, in turn, minimize the wastage of repeat testing and unnecessary therapy to create a sustainable healthcare industry. International and regional directives/requirements on metrological traceability of calibrators and control materials are in place. Metrology institutes worldwide maintain infrastructure for the practical realization of metrological traceability and demonstrate the equivalence of their measurement capabilities through participation in key comparisons organized under the auspices of the CCQM. These institutes provide certified reference materials, as well as other dedicated value-assignment services benefiting the in-vitro diagnostic (IVD) industry, reference (calibration) laboratories and the clinical chemistry laboratories. The roles of these services in supporting national, regional, and international activities to ensure the metrological traceability of clinical chemistry measurements are described. Graphical abstract.

Testosterone in human serum is commonly tested in clinical laboratories using immunoassay methods as well as liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods. To standardize and ensure the accuracy of the measurement results, reference procedures with higher metrological order are required. A simple measurement procedure based on one-step liquid-liquid extraction (LLE) and liquid chromatography-isotope dilution tandem mass spectrometry (LC-IDMS/MS) was developed for total testosterone in human serum. The procedure involved serum spiked with 13 C 3 -testosterone, equilibration for 2 h, and extraction with an organic solvent. Testosterone certified reference material (CRM) was used as the calibration standard to ensure the traceability to the International System of Units (SI). Testosterone in serum CRMs from the National Institute for Standards and Technology (NIST) and LGC were used to validate the accuracy of the newly developed method. The deviations of the obtained values from the NIST and LGC certified values ranged from -0.55% to 0.45%. Similarly, the coefficient of variations (CVs) of the replicate measurements were in the range of 0.55% and 0.78%, respectively. The relative expanded uncertainties were comparable with those of the certified materials. The newly developed LC-IDMS/MS procedure demonstrated adequate trueness and precision, and was simple to perform. The method can be used for value assignment of testosterone in external quality assessment (EQA) materials as well as certification of CRMs in the future. Graphical abstract.

Background The measurement of hemoglobin A1c (HbA1c) is important for diagnosing diabetes mellitus as well as assessing glycemic control in diabetic patients. Commutable whole blood certified reference materials (CRMs) are needed in the measurement of HbA1c for method validation and/or as quality controls. Methods We developed three levels of hemolyzed whole blood CRMs for HbA1c. The certified values were determined using liquid chromatography-isotope dilution tandem mass spectrometry method (LC-IDMS/MS) where two "signature" hexapeptides of HbA1c and hemoglobin A0 (HbA0) were used as the calibration standards. The concentrations of the hexapeptide solutions were determined by amino acid analysis by the LC-IDMS/MS method using amino acid CRMs as the calibration standards. The commutability study was conducted by measuring 25 patient specimens and the whole blood CRMs by both LC-IDMS/MS method and various routine methods using six different clinical analyzers. Results The certified values were determined to be 35.1±2.0, 50.3±1.9 and 65.8±2.6 mmol/mol, respectively. These CRMs showed good commutability on five of the six clinical analyzers but showed poor commutability on one of the clinical analyzers that used similar method as two other analyzers where good commutability was observed. Conclusions With certified target values based on metrological traceability and good commutability on most of the clinical analyzers, the developed whole blood CRMs can be used for method validation or as quality control materials in the measurement of HbA1c. The commutability study results also underscored the need of commutability testing of clinical CRMs using various clinical analyzers.

A gas chromatography-isotope dilution mass spectrometry (GC-IDMS) technique was developed for the quantification of two heavy polyaromatic hydrocarbons (PAHs), benz[a]anthracene and benzo[a]pyrene, in yerba maté tea (maté). The optimisation of two extraction methods, namely liquid-liquid extraction and accelerated solvent extraction, was carried out. Both optimised methods were validated using a certified reference material of fine dust and the results were within the expanded uncertainties at 95% confidence level. Recoveries of 99.2-106.7% with RSD of measurements of 1.1-2.3% were achieved for benz[a]anthracene. Recoveries of 95.7-101.9% with RSD of measurements of 0.4-1.4% were achieved for benzo[a]pyrene. The validated methods were applied for the extraction of benz[a]anthracene and benzo[a]pyrene in maté powder from NIST. A metrological approach was undertaken to ensure the traceability of measurement results. The uncertainties associated with the results were rigorously evaluated and also reported herein. Graphical abstract Quantification of benz[a]anthracene and benzo[a]pyrene using IDMS.

The aim of this research was to investigate the presence and daily variability of pharmaceuticals and personal care products (PPCPs) in public swimming pools. Various types of public swimming pool water were analysed, taken from freshwater indoor swimming pools, outdoor swimming pools, spa pools and seawater swimming pools. Swimming pool water samples were analysed for 30 PPCPs using solid phase extraction (SPE) followed by isotope dilution liquid chromatography tandem mass spectrometry (LC-MS/MS). All PPCPs were below quantification limits in seawater pools. However, caffeine was detected in 12 chlorinated swimming pools at concentrations up to 1540 ng/L and ibuprofen was observed in 7 chlorinated pools at concentrations up to 83 ng/L. Caffeine and ibuprofen concentrations were below quantification limits in all fill water samples, eliminating this as their source in swimming pools. High variations in caffeine concentrations monitored throughout the day roughly reflect bather loads in swimming pools. Future monitoring of these compounds may assist in evaluating what portion of organic matter measured in swimming pools may come from human excretions.

To achieve fast and accurate analysis of carbamazepine in surface water, we developed a novel porous membrane-protected micro-solid-phase extraction (μ-SPE) method, followed by liquid chromatography-isotope dilution tandem mass spectrometry (LC-IDMS/MS) analysis. The μ-SPE device (∼0.8 × 1 cm) was fabricated by heat-sealing edges of a polypropylene membrane sheet to devise a bag enclosing the sorbent. The analytes (both carbamazepine and isotope-labelled carbamazepine) were first extracted by μ-SPE device in the sample (10 mL) via agitation, then desorbed in an organic solvent (1 mL) via ultrasonication. Several parameters such as organic solvent for pre-conditioning of μ-SPE device, amount of sorbent, adsorption time, and desorption solvent and time were investigated to optimize the μ-SPE efficiency. The optimized method has limits of detection and quantitation estimated to be 0.5 ng L(-1) and 1.6 ng L(-1), respectively. Surface water samples spiked with different amounts of carbamazepine (close to 20, 500, and 1600 ng L(-1), respectively) were analysed for the validation of method precision and accuracy. Good precision was obtained as demonstrated by relative standard deviations of 0.7% for the samples with concentrations of 500 and 1600 ng kg(-1), and 5.8% for the sample with concentration of 20 ng kg(-1). Good accuracy was also demonstrated by the relative recoveries in the range of 96.7%-103.5% for all samples with uncertainties of 1.1%-5.4%. Owing to the same chemical properties of carbamazepine and isotope-labelled carbamazepine, the isotope ratio in the μ-SPE procedure was accurately controlled. The use of μ-SPE coupled with IDMS analysis significantly facilitated the fast and accurate measurement of carbamazepine in surface water., (Copyright © 2016 Elsevier B.V. All rights reserved.)

A range of trace chemical contaminants have been reported to occur in swimming pools. Current disinfection practices and monitoring of swimming pool water quality are aimed at preventing the spread of microbial infections and diseases. However, disinfection by-products (DBPs) are formed when the disinfectants used react with organic and inorganic matter in the pool. Additional chemicals may be present in swimming pools originating from anthropogenic sources (bodily excretions, lotions, cosmetics, etc.) or from the source water used where trace chemicals may already be present. DBPs have been the most widely investigated trace chemical contaminants, including trihalomethanes (THMs), haloacetic acids (HAAs), halobenzoquinones (HBQs), haloacetonitriles (HANs), halonitromethanes (HNMs), N-nitrosamines, nitrite, nitrates and chloramines. The presence and concentrations of these chemical contaminants are dependent upon several factors including the types of pools, types of disinfectants used, disinfectant dosages, bather loads, temperature and pH of swimming pool waters. Chemical constituents of personal care products (PCPs) such as parabens and ultraviolet (UV) filters from sunscreens have also been reported. By-products from reactions of these chemicals with disinfectants and UV irradiation have been reported and some may be more toxic than their parent compounds. There is evidence to suggest that exposure to some of these chemicals may lead to health risks. This paper provides a detailed review of various chemical contaminants reported in swimming pools. The concentrations of chemicals present in swimming pools may also provide an alternative indicator to swimming pool water quality, providing insights to contamination sources. Alternative treatment methods such as activated carbon filtration and advanced oxidation processes may be beneficial in improving swimming pool water quality., (Copyright © 2014. Published by Elsevier Ltd.)

A high-accuracy double isotope dilution mass spectrometric method using an exact matching approach with GC coupled to a mass spectrometer for the analysis of cyanuric acid in fortified milk powder was developed. Various parameters for sample clean-up such as the type of SPE cartridge, GC column and type of derivatizing agent used were investigated. The method was found to be linear in the concentration range of 0.03 to 2 mg/kg of cyanuric acid in milk powder. LOD and LOQ were found to be 0.9 and 3 μg/kg, respectively. Recoveries in the range of 95.7 to 102.2% were obtained for the in-house fortified milk powder samples, with RSD of measurements in the range of 0.2 to 3.0%. A metrological approach was undertaken to examine all possible biases that contributed to the combined measurement uncertainty of the method. This high-accuracy method can serve as a reference method for techniques commonly applied in routine testing laboratories., (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A GC-high-resolution isotope dilution MS (IDMS) method for the quantification of melamine in milk powder is described. The developed technique is compared to the LC-IDMS/MS technique, typically used for the determination of melamine in various matrices. The accuracy of the GC-high-resolution IDMS method was demonstrated when a small degree of equivalence was obtained in a regional comparative study involving the determination of melamine in milk powder., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Triphenylamine derivatives bridged by methylene units afford a near planar molecular platform in a series of one dimer and two oligomers exhibiting increased structural rigidity compared to that of their parent triphenylamines. This series of dendrimers show significantly enhanced two-photon absorptions that are up to 3-fold that of triphenylamines with similar molecular size and structure.

[structure: see text]. An X-ray crystallographic study of zinc(II) 5,15-di-(2-methoxymethylphenyl)-porphyrin indicates that it forms a coordination polymer through ligation of the ether oxygen atoms on the porphyrin peripheries to the metal centers of two identical adjacent porphyrins. This gives a novel extensively linked, three-dimensional polymeric structure in which the zinc(II) metal forms a six-coordination center. The uniquely structured network has cavities between 4.81 and 9.27 angstroms, which makes it resemble molecular sieve materials.