摘要:

Human mitochondrial DNA (mtDNA) becomes extremely important for identity testing when genomic DNA is in insufficient quantity or compromised due to decomposition, fire, environmental insults, or aging. The hypervariable (HV) regions of the mitochondrial genome are the most polymorphic and therefore the most informative when identity testing is necessary. A preliminary study was conducted in order to determine if restriction enzyme digestion of these HV regions could generate sufficient information for screening mitochondrial DNA samples prior to more sophisticated analysis. DNA was extracted from blood stains obtained from 80 non-related individuals using the ChelexRmethod. The 1.3 kilobase (kb) control region was amplified, using the polymerase chain reaction (PCR) method, and the 2 HV regions were subsequently amplified using nested PCR. These two regions were then tested with 22 different restriction enzymes and the resulting products were visualized on agarose gels. Results show that a battery of 5 restriction enzymes (Hinfl, KpnI, MboI, TaqI, RsaI) demonstrated significant variation in HV region 1. Almost half, 44%, of samples could be screened into specific groups by digestion in HV1. HV region 2 did not show significant polymorphism with any of the 22 restriction enzymes tested. The results and applications are discussed.

ISSN:0003-2719    

DOI:10.1080/00032719908542888

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

An electrochemical method using linear sweep voltammetry techniques was developed to determine nitrite ion in aqueous solution in the presence of nitrate. Nitrite solutions exhibited a well-defined oxidation wave at +1.0V vs SCE at vitreous carbon, while no oxidation process was observed for nitrate solutions. The pH of the nitrite solutions varied from 2.37 to 5.60 and no change was observed in the Ep values, except for the pH 5.60 solution, where little change was verified. The potential also did not vary with change in the nitrite concentration in the 5.0 x 10−5to 7.0 x 10−4mol L−1range. Very good straight lines for plots of current versus nitrite concentration in the 7.0 x 10−5to 7.0 x 10−4mol L−1range were obtained; the correlation coefficient was never worse than 0.990. The nitrite determination was also performed in the presence of 1.0 x 10−3mol L−1of NO3−ions. The addition of NO3−did not change significantly the current values even when it was added in one hundred times molar excess.

ISSN:0003-2719    

DOI:10.1080/00032719908542889

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A novel chemiluminescence (CL) flow system for sulfite with flow-injection analysis is presented in this paper. It is based on the weak chemiluminescence produced by auto-oxidation of sulfite in the presence of Rh6G, immobilized electrostatically on a cation exchange column. Tween 80 surfactant micelles showed a strong enhancement effect on this weak chemiluminescence. The system responds linearly to sulfite concentration in the range of 0.01-5 mg 1−1(r2=0.996) with a detection limit (3σ) of 0.01 mg 1−1. Interfering metal ions coexisting in sample solutions could be effectively eliminated on-line by an upstream cation exchanger. A complete analysis could be performed in 1 min with a relative standard deviation of less than 5% (n=11). The system is stable for over 500 determinations and has been successfully applied to the determination of sulfite in VK3injections and sulfur dioxide in air.

ISSN:0003-2719    

DOI:10.1080/00032719908542890

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A simple method for the direct determination of trace molybdenum in low alloy steel and pure iron with selectivity and sensitivity is reported. In the presence of TritonX-100 and sulphuric-phosphoric acid medium, a new chromogenic reagent dimethoxyhydroxyphenyl-flurone (DMHPF) forms a red complex with molybdenum(VI). The molar absorptivity is obeyed from the range of 0˜ 8 μg/25 ml for molybdenum(VI). Most of metal ions and 35000-fold amounts of iron do not interfere with the determination of molybdenum. The proposed method has been successfully used for the determination of trace amounts of molybdenum in steel and pure iron specimens.

ISSN:0003-2719    

DOI:10.1080/00032719908542891

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Seven aliphatic alcohols were derivatized to dithiocarbonates under phase transfer catalysis by tetrabutylammonium hydrogen sulphate and directly determinated by capillary zone electrophoresis. A satisfactory separation was achieved within 6 min. Theoretical plates ranging from 500,000 to 136,000 were achieved. The analysis was carried on a bare fused-silica capillary with an electrolyte of 10 mM borate buffer (pH 9.2) and detection at 300 nm. Calibration graphs were linear. The reproducibility in terms of the migration times was less than 0.3% R.S.D. and in terms of corrected peak area was better than 5% R.S.D. The detection limits ranged from 1.470 μg/ml to 7.906 μg/mL for alcohols of different chain length.

ISSN:0003-2719    

DOI:10.1080/00032719908542892

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Racemic 4-aryl-1,2,3,4,5,6,7,8-octahydroquinazoline-2-thiones were resolved into their enantiomers by HPLC on cellulose tris(4-methylbenzoate) coated on silica gel using ethanol:n-hexane (70:30) as a mobile phase. A convenient method for preparation of cellulose tris(4-methylbenzoate) chiral stationary phase was described and the enantiomers were characterized by some chromatographic data.

ISSN:0003-2719    

DOI:10.1080/00032719908542893

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

A mixed SDS micelle and BSA buffer system was used in the micellar electrokinetic chromatography (MEKC) separation of hematoporphyrin derivatives (HPD) at pH 8.0 with untreated capillaries. The effects of altering the composition of sodium dodecyl sulfate (SDS) electrolyte solution on the separation efficiency of the hematoporphyrin derivatives were presented. The results show that separation efficiencies were enhanced by using a mixture of SDS and BSA. The results demonstrated that CE methodology can compete with well-established techniques such as HPLC for the separation of biomedical and pharmaceutical samples with regard to time and expense of analysis.

ISSN:0003-2719    

DOI:10.1080/00032719908542894

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor