In this paper the advances in gas chromatography devoted by chinese scientists in China, were described. This review is divided 3 parts. This is 3rd part which contains. 8. GC application of efficacious component analysis in foodstuff. 9. GC application of wines.analysis. 10. GC application of contaminant analysis. 11. GC application of petroleum and petrochemical analysis. 12. GC application of chemicals analysis.
Acid brown NR (ANR) could combine with albumin such as bovine serum albumin (BSA) or human serum albumin (HSA) in acidic Britton-Robinson solution and produce a undissolved precipitation. Based on the decrease of ANR absorbance, a new method for determination of albumin was developed by spectrophotometry. Under the optimum reaction conditions, the linear ranges for the determination of BSA and HSA were 28.0～112.0 and 24.4～122.0 mg/L with absorption coefficient e_(BSA)=1.4×10~6 L·mol~(-1) ·cm~(-1), e_(HSA)=1.3×10~6 L·mol~(-1)·cm~(-1), respectively. The relatively standard deviation and the recovery for the determination of total proteins in 7 human serum samples were 0.83%～3.02% and 90.90%～109.80%, respectively. The results of the determination were in agreement with that by Biuret method.
A new spectrophotometric method for the determination of trace amount of Vanadium was developed. It is based on the catalytic effect of trace vanadium on the discoloring oxidation of methyl green by KBrO_3 in the presence of Vc in the medium of H_3PO_4. The optimum conditions of the catalytic reation have been studied. The linear range of Ⅴ(V) is 0～1.00 ng/10 mL, and the detection limit is 5.20×10~(-12) g/mL. The method has been used for the determination of trace Vanadium in celery and wheat with satisfactory results.
A Spectrophotometric method for the determination of Flavone in the extract of ginkgo biloba leaves (FEGb) was established. In the solution of NaNO_2 and pH 13.20～13.60, FEGb reacts with Al(NO_3)_3 to form a stable and sensitive pink complex, its maximum absorption wavelength is λ_(max)=510 nm. The absorbance (A) was linear with the concentration of FEGb in the range of 4.606～55.27 μg/mL, the method could be opplied to indirect determination of FEGb.
The trace organic pollutants in industrial waste water were separated and enriched by solvent sublation, and were determined by GC-MS in this paper. The parameters of affecting solvent sublation were optimized by using typical compounds in the waste water. The method developed has been applied to measure 39 trace organic pollutants in waster water from a petrochemical factory. The results show that it is a fast, simple and feasible pretreatment method in water quality analysis.
Two types of background correction techniques of commercialized instruments marketed since 2004 are detailed discussed and analyzed in detail based on theory,development and formation,as well as the analytical performance.
In a NH_3-NH_4Cl buffer solution of pH 8.40, Yttrium(Ⅲ)reacts with 3-Thiazolylazo-5-Aminophenol to form a complex which produces a sensitive polarographic wave at the potential of -0.67 V (vs. SCE). The second-order derivative peak current is linear to the concentration of Yttrium(Ⅲ), in the range of 1×10~(-7)～8×10~(-4) mol/L, with the detection limit of 8×10~(-8) mol/L. Several electrochemical methods were used to study the properties of the wave. It was proved to be an adsorptive wave of the complex of yttrium. The electrode reaction is an irreversible reduction process, and the number of electron transfer is 2. The effects of many ions on the peak current were tested. The proposed method was used to determine the trace yttrium in tea with satisfactory results.
An electrophoretic method was established for the determination of mexiletine,lidovacaine and bupivacaine in plasma.The plasma was extracted by ether,and the extract was evaporated to dryness.The residue was reconstituted and injected for analysis.The electrophoresis conditions were as follows: running buffer 75 mmol/L NaH_2PO_4(pH 3.0),temperature 30 ℃,voltage 26 kV,UV detection at 200 nm,pressure injection for 5 s.The established method has good linearity and precision in the range of 0.1～4.0 μg/mL,which is suitable for routine monitoring.
L-cysteine-capped nano-ZnS particles (ZnS-Cys) as fluorescence probes have been successfully synthesized. The resonance light scattering (RLS) of ZnS-Cys in pH 5.12 NaAc-HAc solution is greatly enhanced by proteins with the scattering peak at 308.0 nm. The enhanced RLS intensity is in proportion to the concentrations of proteins. A sensitive RLS method for determining micro-level proteins has been developed. ZnS-Cys are non-toxic and stable, permitting highly resistant to photobleaching. The method has been applied to determine total protein in human serum samples with satisfactory results.
A method for the determination of trace arsenic in sulphur by HG-AAS after oxygen bomb combustion has been established. Sulphur was pretreated with oxygen bomb cornbustion, and arsenic in the crystals of sulpher was released and absorbed into the solution of NaOH. Arsenic was reduced to As(Ⅲ) by ascorbic acid, and then determined by HG-AAS under optimum conditions.
The capillary gas chromatographic method was introduced for the determination of organochlorine pesticide residues in medicinal plants of Epimdium biolba,Cassia nomame, Anthocyanidins, Rhodiola rosea, Safflower and Pueraria Root. The organochlorine pesticides were extracted from samples by micro-chemical technique. Then, the extracts were cleaned up by solid phase extaction, and separated by HP-5 capillary column with micro-electron capture detector. The average recovery was 92.16%～100.59% and RSD was 0.5%～4.2%. The limits of detection were 1.4×10~(-14)～1.2×10~(-12) g. This method is rapid, sensitive, accurate and suitable for analysis of pesticide residues.
AbstrcatThe HPLC Fingerprints of rhizoma anemarrhenae was established,based on chromatograms of 8 batches of samples ,which obtained from different sources. The Zorbax Eclipse XDB-C_(18) column(5 μm, 4.6×250 mm, Agilent)was used as an analytical column with the mobile phase A:acetonitrile and B: 25 mmol/L phosphate buffer with gradient elution in 60 min. The flow rate was 1.0 mL/min and the column temperature was controlled at 25 ℃, and the detection wavelength was set at 257 nm. 6 common peaks were found in the fingerprints of 8 batches of rhizoma anemarrhenae, and good similarities with correlation coefficients higher than 0.9 were found in fingerprints between the herbs from different sources and the standard chromatographic fingerprint, which can be utilized for the identification of rhizoma anemarrhenae. The method is accurate and reproducible, providing a new reference for quality control of rhizoma anemarrhenae.
By investigating the MS behaviors of sinomenine (basic model compound) and rhein (acidic model compound) at five concentrations in six different kinds of buffer, we have investigated matrix effect in positive and negative ion mode to study the LC buffer systems matching MS analysis from system adaptability and signal intensity improvement. These results show different buffer systems have different matrix effects on ionization efficiency, and we should select appropriate buffer according to the analytes.
The effects of the concentration and volume of ethanol, times and temperature of reflux, kind of extracting solvent on the extract of lactone components were studied. The extract mehtod was evaluated by the total content of four kinds of lactone as the index components. The optimum extract conditions were obtained: 10 fold of 75% ethanol was added to the Chuanxiong raw drug materials, reflux was carried out at 60 ℃ water bath for 2 times. The ethyl acetate was choosed as an extracting solvent to separate the lactones from the concentrated Chuanxiong ethanol extract, and the optimal volume of ethyl acetate was 11 mL to 1 g Chuanxiong raw drug materials. The content of total lactone components in the extracted samples were 24%～30%. A HPLC method was used to determine the content of lactone components in the experimental samples.
The product which formaldehyde reacts with Ethyl acetoacetate and ammonia is 2,6-Ddimethyl-3,5-bis(ethoxycarbonyl)-1,4-dihydropyridine in acidic acetate buffer. The product of the reaction has maximum absorption at 375 nm and the molar absorptivity e_(375) is 5.533×10~3 mol/cm/L. A new method for the determination of formaldehyde has been developed with this reaction and the linear range is 0.08～4.0 mg/L.
AbstrcatThe reduction wave of Hexamethylenetetramine-β-CD appeared at ca. (0.80 V (vs. SCE) in 0.05 mol/L KH_2PO_4-Na_2HPO_4 (pH 6.24) solution. In the presence of H_2O_2, the reduction wave is catalyzed to produce a parallel catalytic wave. Based on the catalytic wave, a novel method for the determination of hexamethylenetetramine is proposed. The peak current of the catalytic wave is rectilinear over Hexamethylenetetramine concentration in the range 4.0×10~(-6)～5.0×10~(-4) (mol/L). The peak current of the catalytic wave is ca. 10 times higher than that of the corresponding reduction wave. The detection limit is 2.0×10~(-6) mol/L. The proposed method can be applied to the direct determination of Hexamethylenetetramine in industrial products.
In the britton-robison medium with pH 2.0,light green SF(yellowish) can bind with protein at room temperature to form a complex,which has a maximum absorption wavelength at 665 nm.The optimum reaction conditions,binding constant and maximum binding number of light green SF to proteins were investigated by spectrophotometry,and a new method for the determination of proteins was developed based on this binding reaction.The linear range for the determination of bovine serum albumin(BSA),human serum albumin(HAS),and Human Immunoglobulin G(IgG) can reach more than 80 μg/mL with the apparent molar absorptivity of 7.25×10~5,7.22×10~5 and 1.84×10~6 L·mol~(-1)·cm~(-1),respectively.A lot of foreign substances do not interfere with the determination of proteins except for the anionic surfactants and cationic surfactants.The results of the determination for the total proteins in human serum samples obtained by this new proposed method,which is of good selectivity and high sensitivity,agree well with those obtained by the coomassie brillant blue G-250 method.
