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Objective To perform a methodological evaluation study of 4 HPLC based systems and a capillary electrophoresis based system , with the International Federation of Clinical Chemistry and Laboratory Medicine ( IFCC) glycated hemoglobin reference method as a comparative method .Methods 40 hemolysis samples of variety concentrations were prepared .The samples were measured by IFCC reference method and 5 glycated hemoglobin testing systems , respectively and trueness verification was performed according to the Clinical &Laboratory Standards Institute (CLSI) guideline EP9-A3.Whole blood samples were used to test the systems'precision, linearity and analytical interferences .Results The average CV of IFCC reference method results of 40 hemolysis samples was 1.4％( range from 0.2％to 2.5％).No outlier was found in the results of the 5 testing system.The slopes ranged from 0.9902 to 1.0267, and intercepts from -0.1526 mmol/mol to +0.1512 mmol/mol, squared correlation coefficient from 0.9962-0.9971, biases at two medical decision level were less than 0.3％HbA1c.Within-laboratory precisions were less than 2％ (NGSP unit).Bias between all test results and predicted results were less than 5％.High concentration of glucose showed certain interference to glycated Hemoglobin tests but had little influence in clinical practice.Conclusions The results of the 5 testing system are comparable to the IFCC reference method , the results of precision and linearity evaluation meet the requirements of related guidelines .
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Objective Improving the existed HPLC methods in order to detect the levels of global DNA methylation rapidly, stably and conveniently. Methods The HP1100 high performance liquid chrom-atographic (HPLC) system was used in this study. The analytic column was Macherey-Nagel (MN) EC 250/4.6 Nucleosil 100-5SA (250mm x 4. 6mm, 5u,m) cation exchange chromatographic column. We used 60mM acetic acid + 15% acetonitrile as mobile phase (adjust to pH =4. 6 by NaOH). The flow rate was 1. 0 ml/min, detective UV wavelength was set to 276 nm and column temperature was set to 28℃. The injection volume was 50μl. The global DNA methylation was expressed as 5mdC/(dC +5mdC) x 100%. Results Under these conditions, we can isolate dC and 5mdC completely in ten minutes. The level of leukocyte global DNA methylation in healthy people is (4. 389 ±0. 0159) %. Conclusions This method can determine the levels of global DNA methylation rapidly, and it can be widely applied in some laboratories.
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Objective To develop an anion-exchange chromatographic method for the determination of trace thiocyanate and iodide. Methods A sample containing thiocyanate and iodide was pumped through a continuous rod anion-exchange column and the two anions were eluted subsequently with potassium bromide and were determined by a UV detector simultaneously. Results It was proved that the chromatographic column could separate thiocyanate and iodide effectively in the optimum conditions. The linear equation of iodide was y=3 272 860x+51 929.537 57, r=0.999 03, the final detection range was 0.30-3.0 mmol/L, the detection limit was 1.27 ?g/L, the recovery rate was 87% and RSD was 2.75%, the linear equation of thiocyanate was y=3 163 690 x+1 057 080, r=0.999 49, the final detection range was 5.0-80 mmol/L, the detection limit was 30 ?g/L, the recovery rate was 85% and RSD was 3.22%. Conclusion This method is simple, reliable, better anti-interference and is applicable to the determination of trace thiocyanate and iodide.
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Objective To develop an ion chromatography (IC) for simultaneous determination of chlorite,chlorate and bromate in drinking water. Methods The IC separation was carried out with the IonPAC AS23 column by using 4.5 mmol/L Na2CO3-0.8 mmol/L NaHCO3 at the flow rate of 1.0 ml/min. The injection volume was 250 ?l,the temperature of conductivity detector cell and column were 30 ℃ and 35 ℃,respectively. The pressure upon the bottle of mobile phase was 40 kPa. The current of auto-regenerating suppressor was 25 mA. Results The results showed that in the range of 0 to 1 000 mg/L, the calibration equation for chlorite was y=0.009 6+1.600 0 x (r=0.999 3),for bromate was y=0.003 2+3.184 7 x (r=0.999 9),for chlorate was y= 0.001 8+1.788 9 x(r=0.999 9).The detection limit of chlorite,chlorate and bromate were all 5 ?g/ L,the recovery rates were 89.0% -108.0% and the relative standard deviations (RSD) were 0.21%-2.70%. Conclusion The method is simple,fast,accurate, sensitive,little interference and is applicable to the simultaneous determination of chlorite,chlorate and bromate in drinking water.
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Objective To determine multiple inorganic anions in drinking water with ion chromatography,such as F~-,Cl~-, NO_2~-,Br~-,HPO_4~(2-),NO_3~-,SO_4~(2-).Methods The ion chromatography was used.The optimized conditions were explored.Results Under the selected flow rate(1.5 ml/min),the optimal concentration of eluent NaHCO_3 and Na_2CO_3 was 2.0?10~(-3)and 3.0?10~(-3) mmol/L,under the concentration of eluent,the optimum pump flow rate was 1.5 ml/min,the recovery rate was 94.69%-102.20%. Conclusion This method is applicable to the determination of multiple inorganic anions in drinking water.
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Objective To observe the concentration change of 0.5% peracetic acid used as disinfectant in the indoor air. Methods KC-6D gas-sampler and ion chromatograph were employed and sampling interval time was 10-15 min, 7 samples were collected each time in both of the condition of closed and ventilated, the same experiment was repeated for 3 times. Results As the time went on, the concentration change of 0.5% peracetic acid in the indoor air increased from 6.24 mg/m3 to 20.72 mg/m3 in the condition of closed and decreased in the condition of ventilated from 6.92 mg/m3 to 3.36 mg/m3. Conclusion In a closed room of 20 m3, using 500 ml 0.5% peracetic acid, after 30 minutes of disinfection followed by 60 minutes of ventilation, the concentration of peracetic acid will be about 3.36 mg/m3 in the air of the room.
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Objective To develop a conductance-ion chromatography for simultaneous determination of 5 anions in drinking water. Methods The orthogonal experiment method L9(34) was used to select the optimum working conditions of IC-2000 ion chromatography. Under the founded chromatography condition, 5 anions in water samples were determined simultaneously after filtered with 0.45 ?m filter membrane. Results Both of the precision and accuracy of this method were desirable, all the relative standard deviation was less than 5.0%, the rates of recovery were 90%-106.7%, the correlation coefficient was more than 0.999 except NO2-(0.990 5). Conclusion This method is simple, accurate, quick and suitable for simultaneous determination of 5 anions in drinking water with no need of sample pretreatment.
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0.999).The relative standard derivations (RSDs) were 0.2%-5.0%, the rates of recovery were 91.1%-108.5%. The detection limits for analysis ranged from 1.3 mg/kg to10 mg/kg. Conclusion The method presented in the paper is sensitive, accurate and suitable for the determination of organic acids cosmetic samples.
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Objective To develop a sensitive, safe and quick method for determination of ammonia in the air. Methods The air samples collected with multi-hole absorbing tubes were determined by ion chromatography after sampling. Results The recovery rates, precision (relative standard deviation) and detection limit were 97.6%-99.8%, 1.08%-2.93% and 0.05 ?g/ml,respectively. There was no significant difference between this method and chemical method. Conclusion The method is simple, quick, sensitive and suitable for determination of ammonia in the air.
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Objective The present paper compared the ion residues including cations residues and anions residues in autosampler plastic vials from 4 different ion chromatography companies and discussed the relationship between soaking duration time and ion releasing. Methods The separation and determination were carried out by IonPac CS12A cation exchange column, MSA isocratic eluent together with suppressed conductivity detector; and IonPac AS15 anion exchange column, NaOH isocratic eluent together with suppressed conductivity detector. 4 plastic vials from 4 companies were soaked in DI water with a particular volume followed by injecting the liquid samples to IC system in order to measure residue ions with low level(?g/L). Results The detection limits were 0.79-5.28 ?g/L.The linear range were 1-20 000 ?g/L for Cl-, NO2-, NO3-, SO42-, Na+, K+, Mg2+, Ca2+. The linear coefficients were 0.998 3-0.999 9. RSDs were below 3%.The recovery rates were 83.3%-112%. Conclusion This method satisfies the requirement of practical examination, and the suitable methods for repairing the plastic vials of autosampler is proposed.