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Precision device for automatic TLC-sample application
Clmrca Chvnrca Acta, 125 (1982) 355-358 Elsevier Biomedical Press
355
CCA 2293
Brief technical
note
Precision device for automatic application
TLC-sample
N. EngstrBm ‘, L. Hellgren ‘,* and J. Vincent ’ yDepartment
of Dermatology, Sahlgren’.~ Hmprtal, Gtehorg (Sweden) and h Department Facult.y of Medicine, Universrty of Trondhernt, Trondheim (Nonvyy) (Received
of Dermatolo~,:
March 2nd; revision June 30th. 1982)
Introduction
For preparative TLC purposes, in most cases, bandwise sample application is preferred. However, manual application of large samples by the aid of a syringe is a tedious procedure. The device here presented allows automatic, narrow band application of samples dissolved in large solvent volumes. General
description
The apparatus (Figs. l-3) consists of a mechanical and an electronic control unit. The mechanical unit comprises the following vital parts: motor with gear-box; threaded spindle; adjustable sloping guide rod; specially profiled horizontal gliding bar; horizontal and vertical carriage with application reservoir syringes and valve regulator; turning point switches. The electronic control unit consists mainly of a speed control for movements in both directions and switch for automatic or manual mode. The carriage with application and reservoir syringe is driven horizontally along the gliding bar in both directions by rotation of the threaded spindle. By left-hand movement the vertical carriage is elevated simultaneously lifting the plunger of the application syringe (filling mode). Then the valve is in a filling position giving a free flow of the solvent between the reservoir and application syringe. By right-hand movement the vertical carriage is lowered, thus pushing the plunger of the application syringe downwards (application mode). The valve is then repositioned for application through the needle. The vertical movements are controlled by the adjustable sloping guide rod working as a rail for a special fitting connected to the rear side of the vertical carriage. The gradient of the guide rod determines the amount of solvent applied to the plate relative to the band length. The horizontal carriage may be manually operated by simple push buttons (manual mode). In the automatic mode, the carriage is moving back and forth according to the desired band length. The * To whom correspondence
0009-898
I /82/0000~0000/$02.75
should
be addressed
0 1982 Elsevier Biomedical
Press
Fig. I. Front we\\, of the wmplete dewce. MU. mechanical unit: KC. electronic control waith gear box: 2. horizontal carriage with application reservoir syringe. valve regulator. switches.
Fig. 2. Rear wew of the mechanical unit. 3. threaded spmdle; 4. adjustable profiled horizontal gliding bar; 6. vertical carriage with a syringe plunger
&pmg bar.
unit: I. nlot<,r turning point
guide rod: 5. especially
357
\ /
\/
Fig. 3. A schematic view of the mechanical unit. 1, plunger head fitting: 2, vertical carriage; 3, application syringe; 4, adjustment screw for needle level; 5, switching lever; 6, turning-point post, left hand; 7, adjustment screw for turning-point post; 8, adjustment screw for levelling of the TLC plate; 9, reservoir syringe plunger; 10, reservoir syringe; 11, flexible silicon tube (for removing air bubbles): 12, addition adjustment of the TLC plate; 13, right hand turning-point post; 14, application syringe plunger; 15, application needle; 16, string-holder for the TLC plate; 17, button stop screw; 18, plate for the horizontal carriage assembly; 19, TLC plate holder: 20, motor with gear box; 21, threaded spindle; 22, adjustable sloping guide rod; 23, especially profiled horizontal gliding bar; 24. free-way valve: 25, cog wheel regulating the valve; 26, cog rod; 27, string device; 28, turning-point switch.
end-points depend on the positions of the two turning-point posts up to full plate length (200 mm). When the carriage reaches the turning point posts, the switching lever is pushed in, releasing a spring device that quickly alters the position of the valve and simultaneously depresses a change-over switch reversing the rotation of the motor. Operating principle Our device permits simple operation. The TLC plate is placed on the adjustable plate holder. The level of the needle tip is adjusted by a precision screw on the vertical carriage to a minimum slit. The turning-point posts are set according to a preselected length of the band. The apparatus is put into a filling mode with the
358
carriage in the starting position. Then the reservoir syringe is filled with sample solution (up to 1 ml). The plunger of the application syringe is removed and the solvent is transferred to the top by carefully pushing the plunger of the reservoir syringe. Thus no air bubbles remain in the system. This is aided by a flexible silicon tube connecting the two syringes. Afterwards the plunger is placed on the application syringe and fitted in the holder connected to the vertical carriage. Switching the device into the automatic mode. the system is ready for application. When the starting switch is activated the application of sample solution commences. Now, the carriage moves automatically back and forth leaving a narrow band with a high degree of accuracy of the sample volumes/length (down to 1 pi/cm). The speed controls are set so that one band is permitted to dry before the next one is superimposed. The procedure is stopped when the gel is sufficiently saturated. By simple replacement of the TLC plate with a new one, the application can be repeated without interruption until all the sample is used. In special cases (sensitive samples), the whole device can be operated under nitrogen in a transparent hood. This device was developed by us to meet the combined requirements of great accuracy and reproducibility with the application of large sample volumes for preparative TLC with a minimum of manual handling.
355
CCA 2293
Brief technical
note
Precision device for automatic application
TLC-sample
N. EngstrBm ‘, L. Hellgren ‘,* and J. Vincent ’ yDepartment
of Dermatology, Sahlgren’.~ Hmprtal, Gtehorg (Sweden) and h Department Facult.y of Medicine, Universrty of Trondhernt, Trondheim (Nonvyy) (Received
of Dermatolo~,:
March 2nd; revision June 30th. 1982)
Introduction
For preparative TLC purposes, in most cases, bandwise sample application is preferred. However, manual application of large samples by the aid of a syringe is a tedious procedure. The device here presented allows automatic, narrow band application of samples dissolved in large solvent volumes. General
description
The apparatus (Figs. l-3) consists of a mechanical and an electronic control unit. The mechanical unit comprises the following vital parts: motor with gear-box; threaded spindle; adjustable sloping guide rod; specially profiled horizontal gliding bar; horizontal and vertical carriage with application reservoir syringes and valve regulator; turning point switches. The electronic control unit consists mainly of a speed control for movements in both directions and switch for automatic or manual mode. The carriage with application and reservoir syringe is driven horizontally along the gliding bar in both directions by rotation of the threaded spindle. By left-hand movement the vertical carriage is elevated simultaneously lifting the plunger of the application syringe (filling mode). Then the valve is in a filling position giving a free flow of the solvent between the reservoir and application syringe. By right-hand movement the vertical carriage is lowered, thus pushing the plunger of the application syringe downwards (application mode). The valve is then repositioned for application through the needle. The vertical movements are controlled by the adjustable sloping guide rod working as a rail for a special fitting connected to the rear side of the vertical carriage. The gradient of the guide rod determines the amount of solvent applied to the plate relative to the band length. The horizontal carriage may be manually operated by simple push buttons (manual mode). In the automatic mode, the carriage is moving back and forth according to the desired band length. The * To whom correspondence
0009-898
I /82/0000~0000/$02.75
should
be addressed
0 1982 Elsevier Biomedical
Press
Fig. I. Front we\\, of the wmplete dewce. MU. mechanical unit: KC. electronic control waith gear box: 2. horizontal carriage with application reservoir syringe. valve regulator. switches.
Fig. 2. Rear wew of the mechanical unit. 3. threaded spmdle; 4. adjustable profiled horizontal gliding bar; 6. vertical carriage with a syringe plunger
&pmg bar.
unit: I. nlot<,r turning point
guide rod: 5. especially
357
\ /
\/
Fig. 3. A schematic view of the mechanical unit. 1, plunger head fitting: 2, vertical carriage; 3, application syringe; 4, adjustment screw for needle level; 5, switching lever; 6, turning-point post, left hand; 7, adjustment screw for turning-point post; 8, adjustment screw for levelling of the TLC plate; 9, reservoir syringe plunger; 10, reservoir syringe; 11, flexible silicon tube (for removing air bubbles): 12, addition adjustment of the TLC plate; 13, right hand turning-point post; 14, application syringe plunger; 15, application needle; 16, string-holder for the TLC plate; 17, button stop screw; 18, plate for the horizontal carriage assembly; 19, TLC plate holder: 20, motor with gear box; 21, threaded spindle; 22, adjustable sloping guide rod; 23, especially profiled horizontal gliding bar; 24. free-way valve: 25, cog wheel regulating the valve; 26, cog rod; 27, string device; 28, turning-point switch.
end-points depend on the positions of the two turning-point posts up to full plate length (200 mm). When the carriage reaches the turning point posts, the switching lever is pushed in, releasing a spring device that quickly alters the position of the valve and simultaneously depresses a change-over switch reversing the rotation of the motor. Operating principle Our device permits simple operation. The TLC plate is placed on the adjustable plate holder. The level of the needle tip is adjusted by a precision screw on the vertical carriage to a minimum slit. The turning-point posts are set according to a preselected length of the band. The apparatus is put into a filling mode with the
358
carriage in the starting position. Then the reservoir syringe is filled with sample solution (up to 1 ml). The plunger of the application syringe is removed and the solvent is transferred to the top by carefully pushing the plunger of the reservoir syringe. Thus no air bubbles remain in the system. This is aided by a flexible silicon tube connecting the two syringes. Afterwards the plunger is placed on the application syringe and fitted in the holder connected to the vertical carriage. Switching the device into the automatic mode. the system is ready for application. When the starting switch is activated the application of sample solution commences. Now, the carriage moves automatically back and forth leaving a narrow band with a high degree of accuracy of the sample volumes/length (down to 1 pi/cm). The speed controls are set so that one band is permitted to dry before the next one is superimposed. The procedure is stopped when the gel is sufficiently saturated. By simple replacement of the TLC plate with a new one, the application can be repeated without interruption until all the sample is used. In special cases (sensitive samples), the whole device can be operated under nitrogen in a transparent hood. This device was developed by us to meet the combined requirements of great accuracy and reproducibility with the application of large sample volumes for preparative TLC with a minimum of manual handling.