Column in gas chromatography

This presentation will help to know about various columns in gas chromatography

1. Presented by – Komal S hambharkar M.Pharm (Q.A.) Guided by- Dr. Pratima T atke Column In Gas Chromatography

2. Column introduction Column Selection Parameters Column classification Packed column Open column Images of column Difference between capillary column and packed column Conclusion References Contents:

3. The column is the most important component of GC. Made up of glass or stainless steel Glass column- inert , highly fragile Here is where the separations take place . All the various equations dependent on properties of the column. Columns

4. The critical parameters for GC column Dimension :internal diameter , column length , film thickness Condition :temperature ,flow rate given a sample, we will need to first choose the stationary phase which works best First pick the type of column, then dimension of column Choice of stationary phase is very important It determines what kind of sample we can run Critical for packed columns, but less so for open column because of high efficiency Column Selection Parameters:

5. The main chemical attribute regarded when choosing a column is the polarity of the mixture, but functional groups can play a large part in column selection. The polarity of the sample must closely match the polarity of the column stationary phase to increase resolution and separation while reducing run time. The separation and run time also depends on the film thickness (of the stationary phase), the column diameter and the column length. Contd..

6. COLUMNS can be classified: COLUMN PACKED COLUMN OPEN/CAPILLARY COLUMN WCOT SCOT PLOT

7. 1.Packed column : Column are made up of glass or tubes of stainless steel , copper or aluminium columns are available in a packed manner Packed columns contain a finely divided, inert, solid support material (commonly based on diatomaceous earth ) which absorbs liquid used as stationary phase Most packed columns are 2 - 20m in length and have an internal diameter of 1- 8mm The ratio of the volume of the stationary phase to the mobile phase ( Vs / Vm ) for the column ranges from 10-20 The no. of theoretical plates per foot length of the column is 100-1000

8. Advantages : Larger sample capacity Disadvantages: Less applicable :fixed gas analysis Lower column efficiency than that of capillary column

9. 2.Open tubular or Capillary column or Golay column Long capillary tubing 10-100 M or more in length Internal diameter 0.3-0.5 Uniform & narrow d.m of 0.025 - 0.075 cm Inner layer of capillary is coated with a very thin film (about 1 the liquid ,which acts as stationary phase The ratio of the volume of the stationary phase to the mobile phase ( Vs / Vm ) for the column ranges from 100-300 which is the main reason behind its high effeciency The loading capacity <0.01 µl Made up of stainless steel & form of a coil Disadvantage: more sample cannot loaded  

10. Capillary column are of Three Types Wall-coated Open Tubular (WCOT) Support-coated Open Tubular (SCOT) Porous layer Open Tubular (PLOT) Wall-coated columns consist of a capillary tube whose walls are coated with liquid stationary phase. In support-coated columns , the inner wall of the capillary is lined with a thin layer of support material such as diatomaceous earth, onto which the stationary phase has been adsorbed SCOT columns are generally less efficient than WCOT columns. Both types of capillary column are more efficient than packed columns .

11. PLOT columns contains a porous layer of a slid adsorbent such alumina , molecular sieves. They are well suited for the analysis of light, fixed gases and other volatile compound.

12. In 1979, a new type of WCOT column was devised - the Fused Silica Open Tubular (FSOT) column FSOT column : They have much thinner walls than glass capillary column The strength is given by polyimide coating They are flexible and wound into coils Advantages are more physical strength, flexibility and low reactivity

13. Parameter Capillary column Packed column Internal diameter 0.3- 0.5mm 1-8 mm length 10-100m 2-20 m Vs / Vm 100-300 10-20 No. of theoretical plates Several hundred thousand Around 20,000 Sample loading capacity lower higher Efficiency of separation Higher Comparatively lower DIFFRENCE BETWEEN CAPILLARY COLUMN AND PACKED COLUMN

14. Parameter Capillary column Packed column Efficiency (plates/m) 2000-400 500-1000 Sample size (mg) 10-75 10-100000 Relative pressure Low High Relative speed Fast Slow Chemical inertness Best Poorest Flexible column yes No Contd..

15. parameters FSWC WCOT SCOT Packed Length 10-1000 m 10-1000m 10-100m 1-6 m Inner diameter 0.1-0.3 mm 0.25-0.75mm 0.5mm 2-4mm Efficiency 2000-4000 1000-4000 600-1200 500-1000 Sample size 10-75ng 10-1000ng 10-1000ng 10-1000000ng Pressure Low Low Low High Speed Fast Fast Fast Slow inertness Best Good Fair Poor Types of columns

16. In Gas Chromatography , the COLUMN is the most important component as it is interaction of analyte with the column’s stationary phase that permits separation of the analyte in the sample. And therefore Column play its vital role in Gas Chromatography being its heart . CONCLUSION

17. Instrumental Methods of Analysis , by Supriya S. Mahajan, page no.287-290 Instrumental Methods Of Chemicaal Analysis by Gurdeep R.Chatwal & Sham K. Anand , 5 th edition , page no. 2.673-2.700 Basic overview on Gas chromatography columns by Md. Musfiqur Rahman , A.M. Abd El- Aty , Jeong - Heui Choi, Ho- Chul Shin, Sung Chul Shin ,and Jae-Han Shim “Principles Of Instrumental Analysis, 5 th ed. by Skoog , Holler, Nieman ” Chapter 27 . https://teaching.shu.ac.uk REFERENCES