MD Abul Azad

Research Associate

azad@uta.edu






Single Column Trapping/Separation and Chemiluminescence Detection for On-Site Measurement of Methyl Mercaptan and Dimethyl Sulfide.

 

Simple and automated method for measurement of methyl mercatan and dimethylsulfide has been investigated. These two are the most odorous among the sulfur gases. The collection and subsequently separation are performed with a single short column packed with silica gel adsorbent without any additional separation column. CH3SH and DMS are separated according to their desorption temperatures and introduced into a chemiluminescence cell in the same order. These two gases are detected based on the strong chemiluminescence reaction with ozone. Linearity of calibration curves with this system is advantageous compared to flame photometric detector. The total system, including a small cylinder for the carrier nitrogen, can be set in a carriable box. The instrument is applicable to breath odor analysis. Also, automated and continuous measurement of room air could be performed with this instrument. During continuous three days toilet air analysis, it was observed that the sulfur gases level increased after becoming dark. The sulfur gases in ppbv level are successfully measured without any big interference and complicated experimental procedure.

 

 

 

 


 

Figure:  Flow diagram of the chemiluminescence measurement system. ND: Nafion dryer, 3SV: three way solenoid valve, FM: flow meter, DC1,2: dummy columns, MFC: mass flow controller, PC: air purification column packed with sodalime and activated carbon, P: airpump, CL cell: chemiluminescence cell, ORC: ozone removing column.

 

 

 


Measurement of nitrophenols in the atmosphere and rain water.

Nitrophenols are hazardous chemicals. Sources of nitrophenols in the atmosphere are mainly from anthropogenic activity. Nitrophenols in the atmosphere and rain water has been measured. Collected sample was preconcentrated and separated with a reverse phase separation column. Using their lipophilic nature separated them on a high efficiency small particle size (2 µm) reverse-phase column. Since their concentration in the atmosphere is very low, highly sensitive detector was required. A simple liquid core waveguide based absorption detector was developed for measurement of nitrophenols. Teflon AF tube was used as flow cell. The acid base (indicators –colorless) properties of nitrophenolic compound turned itself to yellowish solution and enhanced the sensivity of detection. By using the gas permeable properties of Teflon AF tube ammonia gas was introduced through the Teflon tube and controlled the flowing solution. Sub ppb level of sensitivity was achieved by this detector.


 

Figure A: Separation of standard nitrophenols and extracted air sample solutions. B: The effect of ammonia introduction to signal response. The concentrations of 2,4-DNP, 4-NP, 2-NP, 3-Me-4-NP and  2-Me-4-NP are 4 , 8, 4, 8 and  4 µg/L, respectively. Chromatogram obtained with ammonia introduction (Red line) and without ammonia introduction (blue line). 



 

Charge detector: A new device for measurement of ionic liquid.


We have developed a three-channel “charge detector” (ChD) devices, fabricated either with ion-exchanger beads or larger area membranes, with varied design and experimental parameters. We studied the effects of varying Vapp, the central channel flow rate (CCFR), electrode placement, outer

channel solution composition, and outer channel flow rates on the current signal (hereinafter we call the integrated value the measured charge signal, Qm) elicited upon injecting an electrolyte into the central channel. We found that, although Qm may not always precisely equal the injected charge (Qi), Qm always monotonically varies with Qi.
The device thus behaves as a pseudocoulometer and allows detection of injected charge regardless of the ability to undergo redox transformation in aqueous solution. The ChD responds to weak electrolytes in a unique manner because the undissociated analyte continues to dissociate as the ions are removed.

                &nbs p;                 &nbs p;                 &nbs p;            

Figure: A: Configuration of a charge detector, B: Response of charge detector for anions connected with ion chromatography.


Education: 

PhD (Environmental Science), Kumamoto University, Japan, 2006.

M.Sc. (Chemistry) Dhaka University, Dhaka, Bangladesh, 1997.

B.Sc. Hons. (Chemistry) Dhaka University, Dhaka, Bangladesh, 1995.

 

Fellowships and Funding


 2003 – 2006 Japan Govt. scholarship for PhD study.

 

 

Presentations


On-site measurement of hydrogen sulfide and sulfur dioxide emission from tidal flat sediment of Ariake Sea, Japan.

42nd annual conference of all chemical society of Kyushu island, Kitakyushu, Japan, July, 2005.

54th annual conference of Japan Society for Analytical Chemistry, Nagoya, Japan, September, 2005.

 

Publications

Md. Abul Kalam Azad, Shin-Ichi Ohira, and Kei Toda

Single Column Trapping/Separation and Chemiluminescence Detection for On-Site Measurement of Methyl Mercaptan and Dimethyl Sulfide

Analytical Chemistry Vol.78 No. 17, pp.6252-6259, September, 2006.

 

Kei Toda, Shin-Ichi Ohira, Md Abul Kalam Azad, “Portable Instrument for On-site Measurement of

Odorous Sulfur Gases”, Proceeding of 2nd International Conference on Environmental Science and Technology, 2006(1), pp. 485 – 489 (2006).

 

Shin-Ichi Ohira, Md. Abul Kalam Azad, Rika Kuraoka, Takayoshi Tanaka, Kotaro Mori and Kei Toda;

Long-term and mobile monitoring of atmospheric sulfur dioxide and hydrogen sulfide at Mt. Aso and Kumamoto city,

Bunseki Kagaku, Vol. 55, No. 2, pp. 109-115, February, 2006.

 

Md. Abul Kalam Azad, Shin-Ichi Ohira, Mitsutoma Oda, Kei Toda;

On-site measurement of hydrogen sulfide and sulfur dioxide emissions from tidal flat sediments of Ariake sea, Japan,

Atmospheric Environment, Vol. 39, No. 33, pp. 6077-6087, October,2005.

 

Md. Abul Kalam Azad, Gobinda N. Paul, Pradip K. Bakshi, Amir H. Khan and Abul Khair; Chemical principles of arsenic removal from drinking water using indigenous materials, Dhaka Univ. Journal of Science, Vol. 51, No. 1, pp. 47-50, January, 2003.

 

Gobinda N. Paul, Md. Abul Kalam Azad, Pradip K. Bakshi, Amir H. Khan and Abul Khair;On possible causes of arsenic in groundwater: a case study in Bangladesh perspective, Dhaka Univ. Journal of Science, Vol. 49, No. 2, pp. 123-130, July, 2001.

Research Profile


Single Column Trapping/Separation and Chemiluminescence Detection for On-Site Measurement of Methyl Mercaptan and Dimethyl Sulfide.

 

Simple and automated method for measurement of methyl mercatan and dimethylsulfide has been investigated. These two are the most odorous among the sulfur gases. The collection and subsequently separation are performed with a single short column packed with silica gel adsorbent without any additional separation column. CH3SH and DMS are separated according to their desorption temperatures and introduced into a chemiluminescence cell in the same order. These two gases are detected based on the strong chemiluminescence reaction with ozone. Linearity of calibration curves with this system is advantageous compared to flame photometric detector. The total system, including a small cylinder for the carrier nitrogen, can be set in a carriable box. The instrument is applicable to breath odor analysis. Also, automated and continuous measurement of room air could be performed with this instrument. During continuous three days toilet air analysis, it was observed that the sulfur gases level increased after becoming dark. The sulfur gases in ppbv level are successfully measured without any big interference and complicated experimental procedure.

 

 

 

 


 

Figure:  Flow diagram of the chemiluminescence measurement system. ND: Nafion dryer, 3SV: three way solenoid valve, FM: flow meter, DC1,2: dummy columns, MFC: mass flow controller, PC: air purification column packed with sodalime and activated carbon, P: airpump, CL cell: chemiluminescence cell, ORC: ozone removing column.

 

 

 


Measurement of nitrophenols in the atmosphere and rain water.

Nitrophenols are hazardous chemicals. Sources of nitrophenols in the atmosphere are mainly from anthropogenic activity. Nitrophenols in the atmosphere and rain water has been measured. Collected sample was preconcentrated and separated with a reverse phase separation column. Using their lipophilic nature separated them on a high efficiency small particle size (2 µm) reverse-phase column. Since their concentration in the atmosphere is very low, highly sensitive detector was required. A simple liquid core waveguide based absorption detector was developed for measurement of nitrophenols. Teflon AF tube was used as flow cell. The acid base (indicators –colorless) properties of nitrophenolic compound turned itself to yellowish solution and enhanced the sensivity of detection. By using the gas permeable properties of Teflon AF tube ammonia gas was introduced through the Teflon tube and controlled the flowing solution. Sub ppb level of sensitivity was achieved by this detector.


 

Figure A: Separation of standard nitrophenols and extracted air sample solutions. B: The effect of ammonia introduction to signal response. The concentrations of 2,4-DNP, 4-NP, 2-NP, 3-Me-4-NP and  2-Me-4-NP are 4 , 8, 4, 8 and  4 µg/L, respectively. Chromatogram obtained with ammonia introduction (Red line) and without ammonia introduction (blue line). 



 

Charge detector: A new device for measurement of ionic liquid.


We have developed a three-channel “charge detector” (ChD) devices, fabricated either with ion-exchanger beads or larger area membranes, with varied design and experimental parameters. We studied the effects of varying Vapp, the central channel flow rate (CCFR), electrode placement, outer

channel solution composition, and outer channel flow rates on the current signal (hereinafter we call the integrated value the measured charge signal, Qm) elicited upon injecting an electrolyte into the central channel. We found that, although Qm may not always precisely equal the injected charge (Qi), Qm always monotonically varies with Qi.
The device thus behaves as a pseudocoulometer and allows detection of injected charge regardless of the ability to undergo redox transformation in aqueous solution. The ChD responds to weak electrolytes in a unique manner because the undissociated analyte continues to dissociate as the ions are removed.

                                                                 

Figure: A: Configuration of a charge detector, B: Response of charge detector for anions connected with ion chromatography.


Education: 

PhD (Environmental Science), Kumamoto University, Japan, 2006.

M.Sc. (Chemistry) Dhaka University, Dhaka, Bangladesh, 1997.

B.Sc. Hons. (Chemistry) Dhaka University, Dhaka, Bangladesh, 1995.

 

Fellowships and Funding


 2003 – 2006 Japan Govt. scholarship for PhD study.

 

 

Presentations


On-site measurement of hydrogen sulfide and sulfur dioxide emission from tidal flat sediment of Ariake Sea, Japan.

42nd annual conference of all chemical society of Kyushu island, Kitakyushu, Japan, July, 2005.

54th annual conference of Japan Society for Analytical Chemistry, Nagoya, Japan, September, 2005.

 

Publications

Md. Abul Kalam Azad, Shin-Ichi Ohira, and Kei Toda

Single Column Trapping/Separation and Chemiluminescence Detection for On-Site Measurement of Methyl Mercaptan and Dimethyl Sulfide

Analytical Chemistry Vol.78 No. 17, pp.6252-6259, September, 2006.

 

Kei Toda, Shin-Ichi Ohira, Md Abul Kalam Azad, “Portable Instrument for On-site Measurement of

Odorous Sulfur Gases”, Proceeding of 2nd International Conference on Environmental Science and Technology, 2006(1), pp. 485 – 489 (2006).

 

Shin-Ichi Ohira, Md. Abul Kalam Azad, Rika Kuraoka, Takayoshi Tanaka, Kotaro Mori and Kei Toda;

Long-term and mobile monitoring of atmospheric sulfur dioxide and hydrogen sulfide at Mt. Aso and Kumamoto city,

Bunseki Kagaku, Vol. 55, No. 2, pp. 109-115, February, 2006.

 

Md. Abul Kalam Azad, Shin-Ichi Ohira, Mitsutoma Oda, Kei Toda;

On-site measurement of hydrogen sulfide and sulfur dioxide emissions from tidal flat sediments of Ariake sea, Japan,

Atmospheric Environment, Vol. 39, No. 33, pp. 6077-6087, October,2005.

 

Md. Abul Kalam Azad, Gobinda N. Paul, Pradip K. Bakshi, Amir H. Khan and Abul Khair; Chemical principles of arsenic removal from drinking water using indigenous materials, Dhaka Univ. Journal of Science, Vol. 51, No. 1, pp. 47-50, January, 2003.

 

Gobinda N. Paul, Md. Abul Kalam Azad, Pradip K. Bakshi, Amir H. Khan and Abul Khair;On possible causes of arsenic in groundwater: a case study in Bangladesh perspective, Dhaka Univ. Journal of Science, Vol. 49, No. 2, pp. 123-130, July, 2001.

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