[Study on Proficiency Testing of Determination Potassium in Serum].

OBJECTIVE: To evaluate the capacity of laboratories participated in the proficiency testing (PT) of determination potassium in serum and improve the quality of testing, and put forward technical suggestions for unsatisfied laboratories. METHODS: According to the requirements of CNAS related documents, the homogeneity and stability of the real PT sample were evaluated by one-way ANOVA and t test, respectively. The values of real PT samples were assigned by reference method which was used in PT results assay. It is required that the deviation of value of real PT samples (code:2, 3, 5) between the measured value and the assigned value shall be within ±15.0%. The precision of values for all samples should not be greater than 3.0%. RESULTS: All the laboratories submitted valid data according to the requirements. Only one laboratory did not meet the requirements, and the satisfaction rate was 90.9%. CONCLUSIONS: The ability of most of laboratories are accurate and reliable.

[Responses of soil moisture and photosynthetic characteristics to mulching materials and ridge-to-furrow ratios in rapeseed fields in southwest dryland of China]. / è¥¿å—æ—±åœ°æ²¹èœç”°åœŸå£¤æ°´åˆ†å’Œä½œç‰©å ‰åˆç‰¹å¾å¯¹è¦†ç›–ææ–™å’Œåž„æ²Ÿæ¯”çš„å“åº”.

In order to deal with the frequent seasonal drought and improve water use efficiency and crop photosynthetic efficiency in drylands of southwest China, a field experiment was conducted to investigate the effects of different mulching materials (common white film, common black film, biodegradable film and no film) and ridge-to-furrow ratios (40 cm:40 cm and 40 cm:80 cm) on soil water storage, as well as photosynthetic characteristics, fluorescence parameters and chlorophyll relative content (SPAD) of rapeseed, with the flat planting as the control. The results showed that the average soil water storage under different mulching materials followed the order: ridge with common black film (BR) ≈ ridge with common white film (WR) ≈ ridge with biodegradable film (BDR) ＞ ridge with no film (NR) ＞ flat planting (FP). Meanwhile, ridge-to-furrow ratios did not affect soil water storage. The net photosynthetic rate, stomatal conductance and fluorescence para-meters (Fm, Fv, Fv/Fm, Fv/Fo, qP and qN) of rapeseed under ridge-furrow with film mulching was higher than those under flat planting. Compared with control, SPAD value was improved by 6.1%, 8.6%, 8.5% and 3.6% under WR, BR, BDR and NR, while instantaneous water use efficiency (IWUE) was increased by 18.3%, 11.4%, 16.3% and 10.4% under those treatments, respectively. Rapeseed yield under BR, WR and BDR was significantly higher than that in control, while NR did not increase yield. The treatment of ridge with common black film + 40 cm:40 cm as ridge-to-furrow ratio could gain the highest economic benefit. Ridge-furrow planting of rainfall harvesting could improve soil moisture, increase crop photosynthetic capacity, and raise yield and economic income in rapeseed fields in drylands of southwest China.

Isolation and characterisation of N-benzyl tadalafil as a novel adulterant in a coffee-based dietary supplement.

A new tadalafil analogue was detected via high-performance liquid chromatography (HPLC)-diode array detection (DAD) during routine screening of health foods suspected of adulteration with erectile dysfunction drugs. The UV absorption spectrum of the unknown was almost identical to that of tadalafil. The analogue was purified by preparative HPLC and structural elucidation carried out by mass spectrometric and NMR spectroscopic experiments. The spectral data revealed that this tadalafil analogue bears a benzyl group instead of the methyl group. The isolated compound was identified as N-benzyl tadalafil. Considering the risk it poses to public health, this new PDE-5 analogues for ED should be included on the inspection list for illegal products.

[Discussion on evaluation mode of proficiency testing for heavy metal and harmful element detection in medicines].

This study aims to explore the evaluation model for the proficiency testing of heavy metal and harmful element residues in pharmaceuticals,and to provide reference for the proficiency testing program and proficiency testing result in the field of residue analysis. The proficiency test result of cadmium determination in honeysuckle as an example. The algorithm A,NIQR,and Horwitz function are used to calculate the assigned value and the standard deviation. Z was obtained at the same time. If | Z | ≤2,the result is satisfactory. If 2< | Z | <3,the result is questionable. If | Z | ≥3,the result is unsatisfactory. In addition,the median value is the assigned value,and deviation(D%) is used. If D% is not more than 16%,the result is satisfactory; if D% is more than 16%,the result is unsatisfactory. After analysis,in the results of questionable or dissatisfied laboratories calculated by algorithm A and NIQR,the deviation error of some data is within the scope of the standard. In the results of the satisfactory laboratory evaluated by the Horwitz function,some data deviation errors far exceed the standard range. The evaluation result of the D% meets the requirements. According to heavy metal and harmful element trace analysis methods,this study is the first to apply D% to the evaluation of the detection ability of heavy metals and harmful elements in pharmaceuticals. This method makes the evaluation result more reasonable,and has important reference significance for the evaluation of other proficiency test results.

[Analysis of the results and methods on proficiency testing of determination of Fe, Mn in drinking water].

OBJECTIVE: To analyse the results and methods on proficiency testing(PT) for determination of Fe, Mn in drinking water and to discuss the influencing factors. With a view to the laboratory for accurate determination of drinking water iron and manganese to provide technical support. METHODS: 180 labs from 30 provinces (cities), autonomous regions took part in the PT. Based on methods of PT, statistical analysis of the results, to find the causes of dissatisfactory results. RESULTS: According to the results of the report for the first time, the PT showed that 85.56% labs presented satisfactory results of determination of Fe and 87.71% labs presented satisfactory results of determination of Mn. In addition to ICP/MS, it showed that 76.00%, 88.89%, 93.75% respectively presented satisfactory results of the methods of AAS, ICP-AES and chemical of determination of Fe. It showed that 79.23%, 94.29%, 72.73% respectively presented satisfactory results of the methods of chemical, AAS and ICP-AES of determination of Mn. The initial results of 37 labs had dissatisfactory. Results of statistics showed that iron, manganese at the same time [ZB] > or = 3 for the 11 labs. CONCLUSION: Most of the labs that took part in the PT have good competence in analyzing Fe, Mn. The main reasons of the dissatisfactory results were larger systematic errors, experimental blank, matrix interference and feeble control ability of the key point of the experiment.

Determination of nitroimidazoles and their metabolites in swine tissues by liquid chromatography.

A liquid chromatographic method was developed for determination of metronidazole (MNZ), ronidazole (RNZ), dimetridazole (DMZ), and 2-hydroxymethyl-1-methyl-5-nitroimidazole (DMZOH) in swine tissue. After extraction with ethyl acetate and evaporation, the nitroimidazoles were redissolved in hydrochloric acid. Hexane was used in the liquid-liquid extraction to remove fat. An Oasis HLB solid-phase extraction was performed after neutralization of the acidic extract. The limits of detection were 1.0-2.0 microg/kg for DMZOH, MNZ, RNZ, and DMZ in muscle and liver. Average recoveries ranged from 80.1 to 83.9% in muscle fortified at 10, 20, and 50 microg/kg; average recoveries in liver ranged from 78.9 to 82.3%. The procedure provides a simple and sensitive method for monitoring DMZOH, MNZ, RNZ, and DMZ residues in swine tissues.