DE1648946B2 - Method and device for determining the total small amounts of organic constituents contained in aqueous liquids - Google Patents

Description

entering gas flow added before this is surrounded in contact tric heating coil, which is able to

comes with the catalyst. the catalyst inside the tube to a temperature

The flame ionization detector, through which the peramr can be heated in the range from 300 to 350 ° C,

Methane formed during the reduction step The flame ionization detector is designed in such a way that

is measured, a commercially available De-5 as described in the aforementioned publication of

be telctor, as described for example generally in the Cropper and K a m i η s k y Ht. Of the

Bri: ischen patent 838 189 is described, wherein the outlet port from the reduction unit is at one

the associated electrical, per se known exhibition point near its connection with the flame

Armor for recording the methane in the ionization detector with an inlet for the

Detector generated signal in visual form application io burner gas, which supplies the detector flame, provided,

can find application. However, a Detek is preferred. The burner gas used consists of a mixture

tor, as stated in the publication by Cropper of 1: 1 volume percent of hydrogen and nitrogen

and K a m i η s k y is described in Analytical stoff.

Chemistry, Vol. 35 (1963), on pages 735 to 743 It has already been pointed out that it would be desirable

is described. 15 is worth seeing, detector and associated recorder

The carrier gas emerging from the reduction stage, to be calibrated from an inert device with known methane volumes. In order to carry out this process, an auxiliary gas flow can, if desired, be arranged directly to the opening, which is led between the outlet of the flame ionization detector. However, it is preferred to lead the exiting gas stream 20 inlet from the oxidation unit and the hydrogen water in a position as close as possible to the outlet opening through a suitable device for absorbing. The auxiliary opening bc of the major part of the existing water vapor, consists of a short, on the outlet channel from which before it is brought to the detector, because the oxidation unit attached side pipe, which is due to the response of the detector to the flexible membrane in the gas flow, through the methane samples einhaltsne methane disadvantageously can be passed through the presence 25 is closed.
excess water vapor is affected. As mentioned above, it is usually desired that in the satisfactory manner one absorbs water vapor in a column of silica gel through which the mass of water vapor is removed from the gas emanating from the reduction stage. For this purpose, the escaping gas let enter. the device is therefore a suitable means of

So that the flame ionization detector removes this water vapor, the signal drawn in the outlet is inserted directly as an indication of the carbon channel from the reduction unit. The content of the samples exposed to the test can expediently be pretiert from, it is necessary, the detector consist of a silica gel column, at least one device using known methane part of this column preferably from silica gel to calibrate the volume. The procedure for the self-35 self-indicating type consists of
This calibration is carried out in more detail below. The method and device according to the invention are described. particularly suitable for determining organic

The device for carrying out the components of the invention in aqueous liquids in the ultra-micro-compliant manner Method is characterized by a scale; for liquids that are an equivalent of Oxidation devices, which contain an in aqueous 40 500 to 5000 ppm carbon, it is possible Liquid samples of insoluble solid oxidation can work with a sample of only two 2μ1 (which is the filled with an injection port for the equivalent of 1 to 10 μg carbon). Prodie Liquid samples, an inlet for an inert substance with a higher carbon content than 5000 ppm Carrier gas and an outlet channel is provided, which are boiled with water before the experiment diluted with a Reduk-45 via an inlet pipe for hydrogen. The time required for this test is up tion unit is connected, in which the carbon on this basis at about 2 minutes, whereby the time Dioxide in the presence of hydrogen to methane starting from the moment the sample is introduced reducing catalyst is located, and the one in the combustion tube until the tip occurs Flame ionization detector is in communication. on the flame ionization detector recorder, in

The oxidation unit can be considered from a vertical 50. The reproducibility of this

Silica or siliceous earth pipes are made, which with the Kup process is reduced to about ± 5 ° / _{0 of} the carbon

fer (II) oxide which is valued for determination by combustion f "'"" ¹ *"" .

of the carbon in organic compounds being ^^ The method according to the invention gives a measure of used quality filled or packed, with a for the total carbon content of the sample, ie the electric furnace is provided, which the temperature 55 amount of organic constituents + · Any of the copper oxide packing to a temperature in the carbon dioxide that may be present. It is true that it increases from 850 to 900 ° C. The upper end of the apparently that the amount of free carbon dioxide is considerable through a suitable flexible silica tube, so this can be closed separately by a reduction membrane, which serves as an inlet opening for methane and measurement through a flame of the liquid sample. The upper end of the Roh- 60 ionization detector in the Vorres described above also carries a side connecting pipe that can be fixed with direction; for this purpose a source of an inert gas, preferably stick sample of the aqueous liquid in the device is connected. through the same auxiliary opening as the one through which the

The reduction unit consists of a vertical metan sample to be introduced for calibration purposes,

tube of heat-resistant glass that is fitted with a 65. To ensure adequate evaporation of the

specially prepared catalyst, consisting of to ensure introduced sample, so that the herein

Fireclay brick stored nickel, is packed (white-contained carbon dioxide through to the reduction unit

For more details see below) and is conveyed by an electrical carrier gas stream, part of the

ß 6th

Outlet channel ays the-y ^ rbrenrMingseinheit-. On which the placed capillary flow meter is measured. $ e, ke "djfr Öiifs_einfüiiröffnuug ,,. die, from the unit The lower end of the combustion tube A is located in a remote location, '^," preferably equipped with an auxiliary connection to an outlet pipe F of about 6 mm heating unit Filling glass outer diameter, which in turn is added to an auxiliary) aigeln ,, and by an electrical 5 device G leads, which is arranged around a length of a heat-sensitive tube, which is able to use a durable glass tube of about 8 mm outside diameter Glaskugeln.iiut a temperature of about 150 ⁰ C knife and with a Chrora-Nickel-Widerz ^ i ^ ringea. , _r,,. .- 'stand wire of 102 cm length and a through _e ^ The Verfäiiren according to the invention is generally from 7.6 μ diameter is wrapped, whose resistance corresponds to anwepdbar aqueous organic compounds is io about 14 ohms and in a spiral from about Holding liquids in which, in addition to the Koh- 9 ^ 9 cm length, and connected to a 12-volt-chip material any or all of the elements water source. In the lower end of the matter, oxygen, nitrogen and chlorine are present; The tube of the auxiliary device G is a side tube./ In φη liquids an excess of volatile liquids can be led to a source of a 1: 1 volumetric ^, norganisctien compounds such as ammonia or is mixture of hydrogen and nitrogen connected ^ hlorwasseEstoiIäure or non-volatile inorganic sen is. The part of the pipe of the auxiliary heating device G, nTsctje components may be present. which is surrounded by the electrical winding is ß ^ Pas method according to the invention can be applied to the filled with glass spheres 2 mm in diameter, the determination of non-volatile at much lower concentrations of silica wool kept in place via stoppers Components (in the range ao. An outlet pipe J leads the auxiliary heating device accordingly from 0.1 to 1.5 ppm) in deminerali- direction G and the hydrogen inlet / leaving fourth water, which in the chemical gas leads to a pipe formed as a pipe Reduktionsßahienstec, hnik and as feed water for high pressure unit K, which is to be used from a heat-resistant glass .d ^ mpfkessei. For this purpose there is a tube of 13 cm length and 6 mm bore, the samples can first be evaporated, both around which an electrical heating device, which is similarly concentrated for example by 100 times, and which is used on the auxiliary punching device G, the amount of concentrated, but necessary for the test, has a resistance of 26 ohms and jProbe can be increased to 10 μΐ. It's also hooked up to a variable, 25-volt supply. The tube K is packed with a recorder device connected to a nickel-firebrick-detector with a catalyst which is operated in situ to a substantially higher degree of sensitivity than the method produced as it is in the dungeon. The case is with samples with a relatively high content of porter and V ο 1 ma η bejOQ organic constituents; in addition, it has been written (published in Analytical Chegewisse minor modifications to the device mistry, Vol. 34 [1962], p. 748). The upper end of the water reduction pipe K , which is desirable by the proportionally larger size, is held by a dryer pipe L , which is 13 cm long and a bore of 6 mm, for the samples provided for the test. These modifications are further extended, which will be discussed in more detail with self-indicating silica gel gejüntea. The method is filled loading, which sits in place with plugs of silica wool ar> a Reproduzibilität of about ± 0-1 ppm coal are held, said turn having a _ienstofi; 40 further dryer column M is connected, which consists of _; Εψ £ example embodiment of the invention a 46 cm long U-tube with a bore of .soll is now explained in more detail with reference to the drawings 5 mm, which are clear with silica gel, .in which mesh size of 0.42 to 0.29 mm is packed. On the F Ljg. 1 shows schematically a device which, for this purpose, is eir exit from this column M. T-piece TV is used to examine aqueous liquids with organic 45, whose side leg P with a source of constituents, with an equivalent of more than a 1: 1 volumetric hydrogen and nitrogen 50Q-ppm carbon; mixture is connected, which is used as burner gas for a _3i F i S- 2 is a schematic representation of the Modi flame ionization detector R The detector R jfikatiqnen, which is based on the in F i g. The device shown in Fig. 1 is tapered with an air inlet S and outlet conduits Γ which are desirable to see, which are provided with suitable amplifying and recording devices when analyzing aqueous liquids; the recorder of the organic components at significantly lower rates has a recording speed of 76 cm /

jCoacentraiions included. ^ _n _ hrs- (30 "/ hrs.). The different units, from

5 In Fig. 1, A is a silica combustion tube which the device consists of can have sleeves

Jje draws a length of about 30 cm and a length of a silicone rubber tube to be connected.

Jnoeal diameter of 7 mm and that is worked with the device as follows:
^ 9 cm long column B made of copper (II) oxide of the micro-

analytical reagent quality is filled in its w structure
Position is held by a Süika wool plug. The device is constructed in such a way that nitrogen is introduced through the jtohr Λ is into a 230 volt electric furnace C with a 60 inlet at a rate of 10 ml / min, bore 20 cm in length and 10 mm in diameter, the hydrogen Stick used so that the copper oxide filling B is completely mixed with substances through the side tube / as Redukinnerhaib of the furnace. The upper end of the tion gas at 20 ml / min and the same mixture combustion tube ^ is stranded with a silicone rubber plug through the side tube P as burner gas at 30 ml / min D , which serves as an inlet opening, as well as 65, air is fed through the inlet S is hot with a side arm E supplied at a nitrogen rate of 400 ml / min; Combustion tube A, auxiliary heating supply is connected, the direction of flow G and reduction tube K having a speed of nitrogen through a temperature of 850 to 900, ISO and 300 to, respectively, which is not shown

7 8

350 ° C. The sensitivity controls on the Flam total carbon content of the original sample from the

Menionization detector recorders are calculated as follows: total carbon content, that represents a top of about two thirds of the full

The deflection after injecting about 20 μΐ methane weight percent / volume = - ⁰ ^ A. 2l = C ₁ ,

through the auxiliary opening H using a 5 FV ₁ Hamilton syringe.

. here A is the net tip area, K _{1 is} the

(b) Calibration of the original sample, which has been converted to volume V ₁

Using a 25 ^ 1 Hamilton syringe, and F is the net tip area factor /

amounts of 5, 10, 15 and 20 μΐ pure Me- io μg carbon, derived from the methane calibration

thans one after the other into the device at the auxiliary diagram.

Opening H introduced. The resulting peaks are carbon dioxide freely present in the sample

The about 45 seconds after each injection is set up by adding 2 μΐ of the diluted sample

drawn. The areas of the tip are injected measured at the injection port H and as above with

(Shown as the product of the height of the apex and the width of the 15 in relation to the total carbon determination.

Peak at half height), the diagram will then The total free carbon dioxide present will be

recorded, consisting of tip area over Koh- calculated from the following equation:

len weight in \ l%, where a μΐ methane is assumed as the equivalent of free CO, (calculated as carbon), to 0.5 μg carbon. As a result

The application should be straight through the ao _{weight percent /} volume = £ * * ■. X ± ₌ C ₂

coordinated zero point result in a line going. FV ₁

(C) Monitoring of oxidation and reduction _{- here B d is the net peak area for the thinned} ,

^sun sample injected at port H.

Using a ΙΟ-μΙ Hamilton syringe 25 Total present in the original sample are different parts of 2.0 μΐ a particularly organic components are then obtained as l prepared ° / _o aqueous solution of glycerol demand C ₁ - C. ₂
inject each other into the device through the injection port D , allowing about 3 minutes to elapse between each injection e) regeneration of the filling of the combustion injection; the needle 30 of the _{tube A and} drying tube L of the syringe is inserted so that it is about 0.63 cm

in the Kupferoxydfüllung B of Verbrennungsroh- It isi required the filling of the combustion B

res A penetrates. Each part of glycerol solution is supposed to regenerate to a tube A as soon as it is found that

Peak of about two thirds of the full scale test attempts on glycerine lead to results,

Blow. The aqueous glycerol used 35 more than 5 ° / ₀ below the calibration level for methane

solution is made by carefully weighing lying areas. This is achieved by using the combustion

1 g of glycerine, which dissolves tube A from the rest of the device to a total volume of 100 ml, and air

is prepared with boiled water; 1 μ! this at a rate of 50 to 100 ml / min

Solution is equivalent to the long-held 3.9fachen the weight l hour through the at 850 to 900 ⁰ C.

in grams de «; used glycerine, expressed 40 content flows. After this treatment will

in μ | Carbon. A blank test is then run through tube A with a nitrogen flow for 5 minutes

Inject through opening D of 2 μΐ of the ab- long cleaned before returning to the device

boiled water, which is combined to produce the.

Glycerin solution was used. The surfaces of the The silica gel dryer tube L is

Methane peaks are measured and the area is separated in each 45 direction as soon as the indicator color changes.

Tip for the water drained from each empty and put in an oven at 130 ° C for regeneration

measurement recorded; the mean net area of the heated content.

Peak is then determined and the carbon content is essentially the same as that described above

in ag of 2μ1 parts of the glycerine solution used device can be used to determine amounts (0.1 to

calculated. The corresponding point on the above 50 1.5 ppm) non-volatile organic matter in

For the calibration diagram described under (b), solid demineralized water will be used, to a certain extent

placed; is the point is within 5 ° _'o of the calibration line, so small changes as schematically ir

it can be assumed that oxidation and Re- F i g. 2, however, are desirable. Ii

production stages work satisfactorily. F i g. 2 represents A the lower end of the combustion *

....,,,. ". , _,.,. , 55 tube, which in its entirety in F i g. 1 shown

(d) is an experiment on the aqueous liquid samples _{; this is by means of a} silicone rubber sleeve mi

Samples of aqueous liquid are used for the test in a T-piece U with a bore of 4 to 5 mn

adjusted by adding boiled water, so connected, the lower leg of which by a

that results in solutions in which 2 al is sealed between silicone rubber plug V. On off

Contains 5 and 10 μg of carbon. ⁶ ° outlet pipe F ' from the T-piece is about 46 cm (18 ")! Ans

The total carbon content of the sample is then d. H. noticeably longer than the corresponding in FIG.

determined by the illustrated pipe F at the opening D 2.0 μΐ. The pipe can expediently

thin solution of the sample in the way for the glycerine to be folded to make the device compact τ

keep the solution injected as described under (c). The other end of the tube F 'is with the

will; an empty test is also carried out on 2μ1 of the 65 lateral leg tube of the auxiliary device G wi

Boiled water carried out as it was connected to the pre- viously. Another in Fig. 2 not dai

position of the sample solution was used. The net peak change of the device can be tx

area for the sample solution is then determined; stand that the silica gel column M in length ai

is elongated about 137 cm (and can also be folded if desired). It is also necessary to increase the sensitivity of the flame ionization detector R by adjusting the attenuation of the amplifier; a five fold increase has been found to be satisfactory, so that 2 micrograms of carbon to 80 ° / ₀ lead of the full scale deflection. This method of making the determinations on demineralized water is also similar to that previously described, the main modifications being (a) the preparation of a starting concentrate by evaporation of a sample

of demineralized water to about -rx ^ - of the original volume, (b) using the test sample (concentrate) of 10 μΐ instead of the sample of 2 μΐ, with the larger sample being injected slowly (over about 5 seconds) into combustion tube A. in order to minimize the disturbance of the flow of the carrier gas due to the evaporation of the water present. The extended outlet pipe F ' acts as a delay pipe and ensures that the methane peak is not recorded until the disturbance has subsided. The water that condenses under these circumstances when it exits the combustion tube A is allowed to collect in the lower limb of the T-piece U and is removed from time to time by inserting the needle of a hypodermic syringe up through the silicone rubber plug V.

A modified calibration is used in which the common methane quantities are one tenth of that given in the above description; instead of using a single glycerine solution before checking whether the device is working satisfactorily, a series of solutions with concentrates of 1, 2, 3, 4 and 5 ° / ₀ each of the concentrations of the individual solution described above are used, 10 μΐ solutions are used in each Case injected. In practice it has been found that the calibration line for these glycerol solutions, if they are plotted in the diagram of tip area over carbon content, does not coincide with the methane line, but lies parallel to the latter with an overlap on the carbon axis between 0 and -0.2 μg . This overlap represents a

ίο represents an "empty" device and, provided that the two lines are parallel and the intersection is not greater than 0.2 μg, the device can be assumed to be working satisfactorily. If the size of the overlap exceeds -0.2 μg, the filling B of the combustion tube A should be regenerated. In all cases, when working according to this modified procedure, the glycerol line and not the methane line should be used as a reference for determining the carbon content of the test samples.

Due to the considerable influence on the accuracy of the results of any organic contamination of the needle of the syringe used to inject the sample concentrates or glycerine calibration solutions that may occur when the needle is inserted through the silicone rubber septum of the injection port D , a modified one is used Injection technique used in which the Hamilton syringe is first filled with about 12 μΐ of the sample or solution and after the needle has been inserted up to about 0.63 (V ₄ ") into the copper oxide filling B of the combustion tube A , the piston is lowered until 10 μΐ remain The syringe is then left in place until the methane spike produced by the initial injection is recorded; the remaining 10 μl of solution are then slowly injected as described above.

1 sheet of drawings

Claims (11)

The Ernndung relates to a method for the patent claims: Determination of the total small amounts of organic components contained in aqueous liquids. 1. The method for determining the total in you also has a device that allows the implementation of small amounts of aqueous liquids 5 of this method, the subject,
Organic constituents, characterized by the fact that a liquid sample is characterized by a liquid sample with certain organic constituents contained in the liquid and insoluble in oxidation, are of great economic as well as social means, which makes them important. In the chemical industry it is so often necessary to carbonize organic constituents of the liquid, the organic content of the water to be oxidized to dioxide, which is then determined to methane, which is chemically reduced during the process by adding hydrogen and using or in processes the mixture is recirculated with a suitable catalyst in order to contact the carbon balance for the process and that the methane formed is increased by calculation. In industry all quantitatively in a flame ionization detector 15, it is desirable to measure the proportion that is organically measured. niche components contained in the water 2. The method according to claim 1, characterized by setting or controlling when the water draws in steam, that the carbon content is used in that of the renewable energy producers. A significant application Aqueous liquids subject to mood find these methods also in the control of is not greater than 5000 ppm. ao industrial and other wastewater that is transported away 3. The method according to claim 1 and 2, thereby. characterized in that previously known methods for determining the or- Copper oxide is used, which on a temporary basis proportions in aqueous solutions are extremely rature in the range of 850 to 900 ⁰ C is kept. time consuming; they usually work with wet oxy- 4. The method according to claim 1 to 3, characterized in that the organic constituents are dated by chemical means characterized in that the oxidation in the presence of agents, for example bichromate, for the production of a stream of an inert carrier gas vorgenom- carbon dioxide, which usually distilled off and in men will. Alkali solution is absorbed, what is classic 5. The method according to claim 4, characterized in that the method for determining carbonate is connected.
shows that nitrogen is used as the carrier gas. The task is to use a method for determining. organic substances contained in aqueous liquids 6. The method according to any one of claims 1 to 5, propose components in which quickly on hand characterized in that as a catalyst for a very small liquid sample erdie a result Reduction level one on firebricks will keep eb-. sorbed nickel layer is used, the avf 35. This object is thereby achieved according to the invention Temperature is kept above 275 ° C. solves that a liquid sample with a fe: ten, in 7. The method according to claim 6, characterized in the liquid-insoluble oxidizing agent that the catalyst is brought to a temperature stirring, whereby the organic When Range of 300 to 350 ° C is maintained. components of the liquid are oxidized to carbon dioxide 8. The method according to any one of claims 1 to 7, 40, which is then reduced to methane, indi m characterized in that the hydrogen is admixed from the Reduk and the mixture is contacted with an ion step exiting gas by means of suitable catalyst and that The methane formed to absorb most of the forehands is quantitatively fed into a flame of water vapor before it is measured in the ionization detector.
Flame ionization detector is initiated. 45 The solid oxidizing agent that is 9. The apparatus preferably used for carrying out the procedure inventive method is proceedings according to claims 1 to 8, characterized oxide of copper, maintained at a temperature in the range of by an oxidation means (A), which is held with 850 to 900 ⁰ C. The conditions under an insoluble in aqueous liquid samples where the liquid sample is filled by the hot copper solid oxidizer (B), which is oxidized with 50 oxyd, may suitably be those of an injection port (D) for the liquid, which is based on the Combustion or solid samples, an inlet (£) for an inert carrier gas position of the carbon in organic compounds and an outlet channel {F) is provided, which has penetrated over itself. The oxidation is carried out in an inlet pipe (/) for hydrogen with a 1 e-essence of a stream of an inert carrier gas, preduction unit (K) , in which e η 55, preferably nitrogen, is carried out, whereby the while the carbon dioxide rend in the presence of water The carbon dioxide formed by the oxidation quatitatively substance to methane-reducing catalyst befir - is transferred to the reducing catalyst. det, and those with a flame ionization - the reducing catalyst can be detector (R) is in communication. act any catalyst that is suitable 10. The device according to claim 9, marked 60 the reduction of carbon dioxide in the presence of records through an auxiliary injection port (//) to perform m hydrogen to methane. A pre-exhaust port (F). the catalytic converter consists of a 11. The device according to claim 10, characterized in that solid stone or the firebrick adsorbed, characterized in that part of the outlet channel (F) nickel layer, which is at a temperature above on the side of the auxiliary injection opening (//) with 6 ₅ 275 ° C, preferably a temperature in the area of an auxiliary heating device (G) is provided. is kept from 300 to 350 ° C. About the reduction of the carbon dioxide, a suitable proportion of hydrogen is added to that from the oxidation stage.