GB823359A - Colorimetric analysis and recording apparatus and method - Google Patents

Abstract

A method of colorimetrically analysing liquid which flows through a chromatographic column and which is pumped to a colorimeter through which the liquid flows and is automatically discharged after analysis, characterized in that a series of measured quantities of the liquid from said column are collected separately in a receptacle and delivered therefrom one after another for flow through the colorimeter for analysis of each quantity of liquid in series in the same order in which they are collected in the said receptacle. A chromatography column 10 supplied at its top with liquid pumped under pressure into said column by a liquid pump 12 connected to the top of said column by a pipe 14. Said column is disposed vertically above a receiver 16 here shown as a vertically positioned glass tube, into which the drops or small quantities of liquid from the outlet 18 of the chromatography column are received. A siphon 20 in the form of a U-tube made of glass or other suitable material is connected to the lower or outlet end <PICT:0823359/III/1> <PICT:0823359/III/2> 22 of receiver 16. The outlet 24 of the siphon is arranged to discharge the liquid, upon operation of the siphon, into a second receiver 26. It will be understood that when the level of the liquid in receiver 16 rises to the level of the top bend 28 of the siphon, the siphon will immediately discharge the contents of receiver 16 into receiver 26. Thus, it will be observed that receiver 16 provides means for collecting the drops or other small volumes of liquid from the chromatographic column to form a predetermined larger volume according to the cross-sectional area of the receiver 16 and the vertical position of the bend 28 of the siphon so that an accurately predetermined volume of liquid considerably larger than the constituent drops or small volumes collected in receiver 16 between successive operations of the siphon is transmitted to the receiver 26, and this operation is repeated at intervals depending upon the length of time required for the rise of the liquid in receiver 16 to the discharge level of the siphon. Provision is made for transmitting each volume of liquid which is discharged into receiver 26 by siphon 20 to a colorimeter indicated diagrammatically at 30 which is arranged to operate an electrically actuated recorder indicated diagrammatically at 34. A multi-compartment turntable or fraction collector rack 36 may be disposed below the outlet 38 of the flow cell of the colorimeter so that the fractions together with the liquid reagent added thereto, as will presently be described, may be received and collected for storage or reference. For this purpose, the fraction collector shown in the prior Specification 679,992, [Group XXX], may be employed, the chromatographic column and its support illustrated in said Specification being omitted. The siphon 20 is preferably adjustable, so that the quantity of liquid which may be collected in the receiver 16 before being emptied into the receiver 26 can be varied and accurately predetermined. Other suitable means may be provided for collecting the drops or other small quantities of liquid to a predetermined volume before the latter is discharged to the receiver 26 for transmission to the colorimeter. As shown in Fig. 5, the receiver 161 is provided with an outlet 221 controlled by a valve 98 which may be opened by solenoid 100. The inlet for receiver 161 which is in communication with the outlet 18 of the chromatography column is indicated at 102 and as here shown a valve 104 may be provided for said inlet. It will be understood that normally, that is, during the collection of the liquid drops in receiver 161 valve 98 is closed and valve 104 is open, as illustrated, and that when solenoid 100 is energized the outlet valve 98 is opened and the inlet valve 104 is closed. Control terminals 106 and 108 suitably electrically insulated from each other are arranged in vertically spaced relation so that when the liquid in receiver 161 reaches a predetermined level solenoid 100 is energized to discharge the collected volume of liquid to the receiver 16. If desired the tube 42 which leads to the pump 40 of Fig. 1 could be connected directly to the outlet 221 so that in such case the liquid would be pumped directly from the receiver 161 to the colorimeter as soon as the contacts 106 and 108 are bridged by the rise of the liquid in receiver 161. Thus, as is obvious without further illustration, contacts 106, 108 could be connected to the trigger circuit such as that shown in Fig. 1 with the inclusion of the winding of solenoid 100 in parallel with the terminals of motor M of the pump.