Simultaneous Screening of Major Flame Retardants and Plasticizers in Polymer Materials Using Pyrolyzer/Thermal Desorption Gas Chromatography Mass Spectrometry (Py/TD-GC-MS).

This study was conducted with the aim of achieving the simultaneous screening of various additives in polymer materials by utilizing a solvent-free pyrolyzer/thermal desorption gas chromatography mass spectrometry (Py/TD-GC-MS) method. As a first step to achieve this goal, simultaneous screening has been examined by selecting major substances representing plasticizers and flame retardants, such as short chain chlorinated paraffins (SCCPs), decabromodiphenyl ether (DecaBDE), hexabromocyclododecane (HBCDD), and di(2-ethylhexyl) phthalate (DEHP). A quantitative MS analysis was performed to check for the peak areas and sensitivities. Since Py/TD-GC-MS is fraught with the risk of thermal degradation of the sample, temperatures during the analytical process were finely tuned for securing reliable results. The instrumental sensitivity was confirmed by the S/N ratio on each component. The detection limits of all components were less than 50 mg/kg, which are sufficiently lower than the regulatory criteria. With regard to reproducibility, a relative standard deviation (RSD) of about 5% was confirmed by employing a spike recovery test on a polystyrene polymer solution containing mixed standard solution (ca. 1000 mg/kg). In conclusion, the results obtained in this study indicate that Py/TD-GC-MS is applicable for the screening of major flame retardants and plasticizers in real samples with sufficient reproducibility at regulatory levels.

Thermal desorption gas chromatography-mass spectrometric analysis of polycyclic aromatic hydrocarbons in atmospheric fine particulate matter.

Thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) is used to analyze polycyclic aromatic hydrocarbons (PAHs) in atmospheric fine particulate matter. However, despite the high sensitivity of TD-GC-MS, the recovery rate of PAHs is greatly influenced by active sites in the equipment. PAHs are decomposed or adsorbed at active sites, decreasing quantitative accuracy. Also, the thermal extraction of PAHs is easily affected by the matrix in PM2.5 samples, decreasing the thermal extraction efficiency. Herein, the analytical sensitivities of PAHs were improved by adding analyte protectant (AP) and thermal desorption aid (TDA) as an auxiliary agent. The combination of 2 µL of 0.5 w/v% D-sorbitol (as AP) and 2 µL of 10 w/v% Tween®20 (as TDA) was found to be most effective in improving the analytical sensitivity of PAHs. The sensitivities of 5-6-ring PAHs with high boiling points increased most when analyzing blank filter papers added with PAHs standard sample or real samples of PM2.5 compared with the samples without the auxiliary agent. When analyzing real samples of PM2.5, the peak areas of 5-ring and 6-ring PAHs in the PM2.5 sample added with the optimized auxiliary agent were 1.40 and 1.96 times that without the auxiliary agent. It is considered that AP in the auxiliary agent covered active sites and protected PAHs undergoing decomposition or adsorption. TDA improved the thermal extraction rate of high boiling point PAHs. When using alternative heat sampling equipment to analyze low concentrations of high boiling point components, the auxiliary agent proposed herein can increase the analytical sensitivity toward the target compounds.

Development of a screening method for phthalate esters in polymers using a quantitative database in combination with pyrolyzer/thermal desorption gas chromatography mass spectrometry.

Seven phthalate esters (di-isobutyl phthalate (DIBP), di-n-butyl phthalate (DBP), benzylbutyl phthalate (BBP), di-(2-ethylhexyl) phthalate (DEHP), di-n-octyl phthalate (DNOP), di-isononyl phthalate (DINP) and di-isodecyl phthalate (DIDP)) were analyzed by pyrolyzer/thermal desorption-gas chromatography/mass spectrometry (Py/TD-GC/MS), the retention index and relative response factor (RRF) relative to DEHP was calculated for each compound and used to construct a quantitative database (qDB). This qDB enables normalization of the retention time and response factor of each phthalate ester between any laboratory simply by analyzing an n-alkane solution and DEHP standard material. This allows for easy calculation of the phthalate ester content of samples without preparation of calibration curves. The efficacy of this qDB method was verified by performing a quantitative analysis of phthalate esters at 4 different laboratories that showed actual retention times were within ±0.012 min of the estimated retention times for all compounds at all laboratories. Similarly, the mean recovery rate (n = 6) at each laboratory was within 79-113%. Quantitative analysis was also performed on 30 real samples using both the qDB method and the Py/TD-GC/MS method set forth in IEC62321-8, which involves the preparation of 1-point calibrations to perform quantitative analysis. The difference in quantitative results between the methods was approximately within ±200 mg/kg for compounds in the concentration region of <2000 mg/kg.

Simultaneous anomalous reflection and quartz-crystal microbalance measurements of protein bindings on a gold surface.

Protein bindings onto a gold surface were detected simultaneously by QCM (delta F(water)) and anomalous reflection (deltaR) of gold on the same surface in aqueous solutions; the obtained delta F(water)/deltaR values correlated with surface areas and viscosity of proteins.

Screening of phthalates in polymer materials by pyrolysis GC/MS.

A study on the rapid identification of phthalates in polymer materials has been conducted by employing gas chromatography-mass spectrometry coupled with a pyrolyzer (Py-GC/MS). Since Py-GC/MS does not require any complex solvent-extraction process, a rapid screening of phthalates should be possible. In this study, polymer samples were directly introduced into the pyrolyzer in order to thermally extract phthalates from the polymer under specific heating conditions. By optimizing the Py-GC/MS parameters, a sequential testing cycle of 35 min per sample was feasible without causing any major decomposition of the base materials. Thus, a rapid screening of over 20 samples per day was achieved without any time constraints by effectively utilizing specifically prepared reference polymer sheets for quality control. Py-GC/MS was found to be suitable and effective for identifying phthalates in polymer materials.

[Total knee arthroplasty for osteoarthritis of the knee].

The indication, preoperative condition, surgical technique and postoperative rehabilitation of total knee arthroplasty for osteoarthritis are summarized. I think the point of contributing to the success of total knee arthroplasty are to discuss the preoperative condition, to know well the instrument, to do the accurate osteotomy and to obtain the correct soft tissue balancing.