Analysis of volatile organic compounds and potential odour compounds in food contact paperboard using headspace two-dimensional GC-QTOF-MS

The objective was to establish a robust and reliable approach for the characterisation of volatile organic compounds (VOCs) present in food contact paperboard. This was achieved through the utilisation of headspace solid-phase microextraction in tandem with comprehensive two-dimensional (2D) gas chromatography (GC) and quadrupole time-of-flight mass spectrometry (HS-SPME-GC × GC-QTOF-MS). The experimental parameters were optimised, involving the use of a DVB/C-WR/PDMS fibre at a temperature of 80 °C for a duration of 30 min. A total of 344 VOCs comprising aldehydes, ketones, alcohols, ethers, esters, alkanes and aromatic compounds, were tentatively identified in the samples. Twelve compounds believed to be from biogenic sources had a high odour impact making them major contributors to potential taint from the paperboard samples. Significant attention should be devoted to five compounds namely, 2-methylnaphthalene, 2-pentyl-furan, furfural, 1-octen-3-one and 1-octen-3-ol due to their potential adverse impact on the organoleptic qualities of packaged food items and their potential toxicity.Abbreviations: C-WR: carbon wide range; DVB: divinylbenzene; GC-MS: gas chromatography - mass spectrometry; GCxGC-QTOF-MS: comprehensive two-dimensional gas chromatography coupled to quadrupole-time-of-flight - mass spectrometry; HS-SPME: headspace - solid phase microextraction; LOD: limit of detection; LOQ: limit of quantification; OAV: odor activity values; PDMS: polydimethylsiloxane; RI: retention index; TTC: threshold of toxicological concern; VOC: volatile organic compound.

Authentication of recycled and virgin polyethylene terephthalate based on UPLC-Q-TOF-MS using non-volatile organic compounds and chemometrics

Plastic packaging waste, such as polyethylene terephthalate (PET) has increased significantly in recent decades, arousing a considerable and serious public concern regarding the environment, economy, and policy. Plastic recycling is a useful tool to mitigate this issue. Here, a feasible study was performed to investigate the potential of a novel method for identifying virgin and recycled PET. Ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was combined with various chemometrics, as a simple and reliable method that achieved a high discrimination rate for 105 batches of virgin PET (v-PET) and recycled PET (r-PET) based on 202 non-volatile organic compounds (NVOCs). Making use of orthogonal partial least-squares discrimination analysis (OPLS-DA) together with non-parametric tests, 26 marker compounds (i.e. 12 intentionally added substances (IAS) and 14 non-intentionally added substances (NIAS) as well as 31 marker compounds (i.e. 11 IAS and 20 NIAS) obtained from positive and combination of positive and negative ionization modes of UPLC-Q-TOF-MS, respectively, were successfully identified. Moreover, 100% accuracy was obtained using a decision tree (DT). Cross-discrimination based on misclassified samples using various chemometrics allowed the prediction accuracy to be improved and to identify a large sample set, thus greatly enhancing the application scope of this method. The possible origins of these detected compounds can be the plastic itself, as well as contamination from food, medicine, pesticides, industry-related substances, and degradation and polymerization products. As many of these compounds are toxic, especially those pesticide related, this indicates an urgent requirement for closed loop recycling. Overall, this analytical method provides a quick, accurate, and robust way to distinguish virgin from recycled PET and thus addresses the issue of potential virgin PET adulteration thereby detecting fraud in the area of PET recycling.

Heparin-induced thrombocytopenia: A critical appraisal of clinical practice guidelines with the AGREE II instrument

BACKGROUND

Despite the availability of clinical practice guidelines (CPGs), the risk of death or thromboembolic complication associated with heparin-induced thrombocytopenia (HIT) remains high. Our aim was to systematically review the quality of CPGs for HIT and summarize the recommendations.

METHODS

CPGs for HIT were systematically searched on PubMed, Embase, guidelines' websites, and Google up to August 6, 2017. Independently, three appraisers assessed the quality of CPGs using the Appraisal of Guidelines for Research & Evaluation II (AGREE II) instrument and extracted the data. Recommendations were summarized, and a comparative study was conducted to analyze the consistency among guidelines.

RESULTS

A total of 11 CPGs were evaluated. The quality assessed by AGREE II varied widely, not only between domains within guidelines, but also between guidelines across domains. The domain of scope and purpose and clarity of presentation obtained the highest median scores, while the domain of rigor of development and editorial independence obtained the lowest median scores. The ACCP guideline and BSH guideline were recommended for use in dealing with HIT, achieving a score of at least 50% in all six AGREE II domains. Recommendations across guidelines were inconsistent, especially in the choice of non-heparin anticoagulant for HIT.

CONCLUSIONS

Future HIT guidelines should place more emphasis on methodological quality and improve efforts to include cost and local availability of drugs when providing recommendations.

Therapeutic drug monitoring of vancomycin: a guideline of the Division of Therapeutic Drug Monitoring, Chinese Pharmacological Society

BACKGROUND

Guideline development should be based on the quality of evidence, balance of benefits and harms, economic evaluation and patients' views and preferences. Therefore, these factors were considered in the development of a new guideline for therapeutic drug monitoring (TDM) of vancomycin.

OBJECTIVES

To develop an evidence-based guideline for vancomycin TDM and to promote standardized vancomycin TDM in clinical practice in China.

METHODS

We referred to the WHO Handbook for Guideline Development and used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system to rate the quality of evidence and grade the strength of recommendations, according to economic evaluation and patients' views and preferences. We used the GRADE Grid method to formulate the recommendations.

RESULTS

The guideline presents recommendations about who should receive vancomycin TDM, how to monitor vancomycin efficacy and renal safety, therapeutic trough concentrations, time to start initial vancomycin TDM, loading dose and how to administer and adjust the vancomycin dose.

CONCLUSIONS

We developed an evidence-based guideline for vancomycin TDM, which provides recommendations for clinicians and pharmacists to conduct vancomycin TDM in China.

Critical Appraisal of the Quality of Clinical Practice Guidelines for Stress Ulcer Prophylaxis

Background and Objective

Inappropriate use of stress ulcer prophylaxis (SUP) is common in many hospitals. High-quality clinical practice guidelines (CPGs) produce better patient outcomes and promote cost-effective clinical care. Thus, the objective of this study was to evaluate the quality of CPGs for SUP.

Methods

A search was conducted for SUP CPGs using PubMed, Embase, China National Knowledge Infrastructure (CNKI), Chinese Biomedical Literature database (CBM), guideline websites and Google (until March 1, 2015). The quality of CPGs was independently assessed by two assessors using the Appraisal of Guidelines for Research & Evaluation II (AGREE II) instrument, and the specific recommendations in the CPGs were summarized and evaluated.

Results

A total of 7 CPGs for SUP were included. The highest median scores were in the clarity of presentation domain (89%), and the lowest median scores were in the editorial independence domain (0%). The rigor of development, stakeholder involvement, and applicability domains all scored below 40%. The specific recommendations for SUP varied, and the recommendations were inconsistent with the supporting evidence.

Conclusions

The overall quality of CPGs for SUP was relatively low, and no specific SUP CPG can be recommended. Not only should the AGREE II instrument be used to determine the quality of CPGs, but also the recommendations should be appraised based on supporting evidence, which would contribute to the development of high-quality CPGs.

Guidelines for therapeutic drug monitoring of vancomycin: a systematic review

BACKGROUND AND OBJECTIVE

Despite the availability of clinical practice guidelines (CPGs) for therapeutic drug monitoring (TDM) of vancomycin, vancomycin serum concentrations still do not reach therapeutic concentrations in many patients. Thus, we sought to systematically review the quality and consistency of recommendations for an international cohort of CPGs regarding vancomycin TDM.

METHODS

PubMed, Embase, guidelines' websites and Google were searched for CPGs for vancomycin TDM. Two independent assessors rated the quality of each CPG using the Appraisal of Guidelines for Research & Evaluation II (AGREEII) instrument and data were independently extracted.

RESULTS

Twelve guidelines were evaluated and the overall quality of guidelines for vancomycin TDM was moderate. The highest score was recorded in the domain of clarity of presentation, and the lowest score was recorded in the domain of rigor of development and stakeholder involvement. The specific recommendations for vancomycin TDM were moderately consistent and guidelines varied in trough concentration monitoring, frequency of TDM, and serum concentration targets.

CONCLUSION

The overall guideline quality for vancomycin TDM was not optimal and effort is needed to improve guideline quality, especially in the domain of rigor of development and stakeholder involvement.

Benefits of therapeutic drug monitoring of vancomycin: a systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

The necessity of therapeutic drug monitoring (TDM) for vancomycin is controversial. The objective of the current review was to evaluate the available evidence for the necessity of TDM in patients given vancomycin to treat Gram-positive infections.

METHODS

Medline, Embase, Web of Sciences, the Cochrane Library and two Chinese literature databases (CNKI, CBM) were searched. Randomized controlled studies and observational studies that compared the clinical outcomes of TDM groups vs. non-TDM groups were included. Two reviewers independently extracted the data. The primary outcome was clinical efficacy of therapy. Secondary outcomes included vancomycin associated nephrotoxicity, duration of vancomycin therapy, length of hospital stay, and mortality. Meta-analysis was performed using the Mantel-Haenszel fixed effect method (FEM). Odds ratios (ORs) or weighted mean differences (WMD) with 95% confidence intervals (95%CIs) were calculated for categorical and continuous outcomes, respectively.

RESULTS

One randomized controlled trial (RCT) and five cohort studies were included in the meta-analysis. Compared with non-TDM groups, TDM groups had significantly higher rates of clinical efficacy (OR = 2.62, 95%CI 1.34-5.11 P = 0.005) and decreased rates of nephrotoxicity (OR = 0.25, 95%CI 0.13-0.48 P<0.0001). Subgroup analyses showed that TDM group had significantly higher rates of clinical efficacy in both cohort studies subgroup (OR = 3.04, 95%CI 1.34-6.90) and in Asian population subgroup (OR = 3.04, 95%CI 1.34-6.90). TDM group had significantly decreased rates of nephrotoxicity in all subgroup. There was no significant difference in duration of vancomycin therapy (WMD = -0.40, 95%CI -2.83-2.02 P = 0.74) or length of stay (WMD = -1.01, 95%CI -7.51-5.49 P = 0.76) between TDM and non-TDM groups. Subgroup analyses showed there were no differences in duration of vancomycin therapy. Only one study reported mortality rates.

CONCLUSIONS

Studies to date show that TDM significantly increases the rate of clinical efficacy and decreases the rate of nephrotoxicity in patients treated with vancomycin.