Abdul Jabbar Laghari

Capillary gas chromatographic determination of methylglyoxal from serum of diabetic patients by precolumn derivatization with 1,2-diamonopropane.

Capillary gas chromatographic (GC) determination of methylglyoxal (MGo) was developed on the basis of precolumn derivatization with 1,2-diaminopropane (DAP) at pH 3. The elution was carried out on an HP-5 (30 m x 0.32 mm i.d.) connected with FID. The linear calibration curve was obtained for MGo within 0.09-1.04 microg/ml with detection limit of 40 ng/ml. Dimethylglyoxal (DMGo) also formed derivative with DAP and eluted and separated from MGo at column temperature 100 degrees C for 1 min with heating rate 30 degrees C/min up to 200 degrees C with run time 4.6 min. The nitrogen flow rate was 1.5 ml/min with split ratio of 10:1, v/v. MGo was determined from serum and urine of diabetics and healthy volunteers. The amounts of MGo from serum and urine of diabetic patients were 0.180-0.260 microg/ml and 0.170-0.250 microg/ml with relative standard deviation (R.S.D.) within 1-4% and 1-3%, respectively. The amounts of MGo from serum of healthy volunteers were 0.032-0.054 microg/ml with an R.S.D. of 1.5-3%. DMGo was not detected from the biological fluids and was used as an internal standard.

New Stationary Phase Material for GC Separation of Organic Compounds

In the past few decades, shape selectivity has drawn a great deal of attention from chromatographers. The chemistry and characteristics of bonded stationary phases such as phase type, length of bonded phase, surface coverage, and silica surface material have an effect on the shape selectivity of the columns. The new packing procedure provided columns with reasonable efficiencies, with high stability. It has several advantages and is constructed of inexpensive, commercially available materials. This new material allows GC analysis to be conducted in any laboratory environment capable of supporting conventional packed column GC and imposes no additional consumable costs. The column has been successfully tested and compared for qualitative as well as quantitative analysis with different correlation of thermodynamic quantities (ΔH°, ΔS°, and ΔG°) versus bonded phase densities and shelf life and robustness of the prepared packed column. The effects of temperature and residual silanol groups are sources of difficulty in elucidation of the mobile phase role in selectivity and retention for GC measurements. The separation occurs by the partitioning of the sample components between two phases. The gas chromatography of volatile organic compounds is superior with regard to the precision and accuracy. Gas chromatography is extensively used for the separation of complex organic mixtures using both packed and capillary columns. Continuous research work is being carried out in order to improve the separation capabilities of the columns for complex mixtures. The literature survey shows that attempts have been made to modify the stationary phase in gas chromatographic columns with addition of inorganic electrolytes or with coordinatively unsaturated metal chelates. As tetradentate Schiff bases are excellent complexing reagents, they form highly stable metal chelates. Therefore, it is considered to examine copper(II) chelate of substituted tetradentate Schiff base as mixed stationary phases together with OV-1 (3%). The proposed stationary phase has not been reported earlier. The obtained results are compared with the well-known GC stationary phase OV-1 (3%). An increase in capacity factor, theoretical plates, and resolution between alcohols, aromatics, and ketones has been observed on mixed stationary phases and compared to OV-1 stationary phase, using same analytical conditions.