TO 7280 – Headspace Oven and TW 7650 – Sample Changer

Headspace Oven and Sample Changer for coulometric KF Titration.

The headspace oven technique of the TO 7280 allows the separation of the water to be titrated from liquid, solid and semi-solid (paste-like) samples.

The sample is weighed in a small glass vessel with lid and septum (vial) and heated in the oven to a defined temperature. A dry air or nitrogen stream flows over a needle through the sample and takes the water with it in a gaseous state. The air or nitrogen together with the water vapor is passed into the titration vessel and the water is immediately titrated coulometrically with the TitroLine® 7500 KF trace.

Headspace Oven and Sample Changer for coulometric KF Titration.

The headspace oven technique of the TO 7280 allows the separation of the water to be titrated from liquid, solid and semi-solid (paste-like) samples.

The advantage of this method is the avoidance of direct contact of the sample with the solvent/anolyte. The anolyte is not contaminated and therefore more samples can be analysed than with direct analysis. As a rule, side reactions do not occur.

The complete system consists of the TO 7280 headspace oven, the coulometric titrator TitroLine® 7500 KF trace and the TW 7650 sample changer. The headspace oven can also be operated without the sample changer with the TitroLine® 7500 KF trace (with or without TitriSoft software).

In combination with the TW 7650 sample changer, up to 49 samples can be analysed.

Titrator TitroLine KF Trace M6 required, sold separately.

General features of the headspace oven and the sample changer

General features :

Semi-automatic or fully automatic water determination
No contamination of the anolyte, generator and indicator electrodes
Application ranges from 35°C – 280°C

The headspace oven technique is suitable for the following samples :

Pharmaceutical products
Natural products
Plastics
Hygroscopic substances
Freeze-dried products, e.g., lyophilisates
Oils and lubricants, creams, pastes
Viscous materials (bitumen, tar, sewage sludge)
Powder and pellets
Food
Petrochemicals

The TO 7280 headspace oven for semi-automatic measuring

If you only have a few samples to measure per day, the semi-automatic headspace oven TO 7280 is the right choice.

Why semi-automatic? The user places the sample in the oven with the crimper and starts the method on the titrator or (optionally) on the TitriSoft software. Apart from entering the sample name and, if necessary, the initial weight, this is all that needs to be done in the next few minutes.

The needle head lowers automatically and the addition of air or nitrogen starts automatically as well.
The desired bake-out temperature is stored in the method and is quickly reached.

Once the final criteria of the method are achieved, the result is displayed and documented and the next sample can be measured.

Special features of the Headspace Oven (TO 7280)

Automatic lowering and raising of the needle head
Automatic switching on and off of the air/gas supply
Can be upgraded to a fully automatic system by connecting the Sample Changer (TW7650)

The TW 7650 sampler for fully automatic measuring

If the number of samples exceeds 15–20/day, it is recommended to use the sample changer TW 7650.

The assembly of the sample changer and oven is within a minute done and immediately ready for use. There is no additional power supply unit or cable required.

Power is supplied via the TO 7280.

The user places the sample vials in the changer and starts the method/work list with the TitriSoft software. The software TitriSoft is required when using the sample changer.

The sample plate rotates to the correct position; the changer head lowers onto the sample vial and sucks the lid tight with a pump. The changer arm moves to the headspace oven and places the sample vial in the corresponding opening.

The needle head lowers and the measurement begins as described on page 4. When the measurement is finished, the needle head lifts and the measured sample is transported back into the sample rack. Then the measurement continues with the next sample.

Special features of the Sample Changer (TW 7650)

Can be upgraded to the TO 7280 oven at any time
Up to 49 samples* can be measured. One position is reserved for the zero-vial to determine the start drift
The start drift can be determined before each sample
Each sample can be measured at a different temperature

Specifications TO 7280 Headspace Oven

Specifications
Sample dosing:	Headspace vials (5 ml…)
Measuring range:	1 μg…100 mg absolute
Resolution:	0,1 μg
Reproducibility:	± 3 μg bei 10 … 1000 μg, 0,3 % bei > 1 mg
Temperature range:	35 °C … 280 °C (isotherm)
Resolution:	0,1 °K
Power supply:	115 … 230 V, 50/60 Hz
Power input:	250 W
Dimensions:	300 x 450 x 240 mm (W x H x D)
Weight:	7 kg
Ambient conditions:	Ambient temperature + 10 … + 40 °C for operation and storage

Specification TW 7650 Auto Sampler

Specification
Number of positions:	49 samples + 1 zero vial
Power supply:	Supply via TO 7280
Power input:	Supply via TO 7280
Dimensions:	420 x 450 x 460 mm (W x H x D) incl. TO 7280
Weight:	10 kg without/17 kg with TO 7280
Ambient conditions:	Ambient temperature + 10 … + 40 °C for operation and storage

Ordering Information TO 7280 and TW 7650

Type No.	Order No.	Description
TO 7280	285227820	For water determination according to Karl Fischer method. Maximum temperature 280 °C. Including power supply for 100 - 240 V
TW 7650	285227830	For the use with headspace oven TO 7280. Up to 50 vials (1 zero vial + 49 samples) with 5 ml size
TW 7650-TitriSoft	285227840	For the use with headspace oven TO 7280. Up to 50 vials (1 zero vial + 49 sample vials) with 5 ml size. With TitriSoft 3.5 P
TO 7280 - TW 7650 set	285227850	Set includes KF headspace oven TO 7280 and the autosampler TW 7650. With TitriSoft 3.5 P
TM 235 TO	285227860	For TO 7280. Scope of supply: basic unit with two 100 ml DURAN ®-bottles including threads, holder TZ 3992 for the bottles, PTFE tubes including screw connections, gas flow meter and holder, 100 vials and grimper, molecular sieve, power supply (110 ... 240 V)

Ordering Information Accessories and Spares

Type No.	Order No.	Description
TZ 3990	285227890	Crimp caps made of aluminum with opening, 10 mm diameter, septa made of silicone/PTFE, 100 pcs
TZ 3993	285227920	Connection tube including screw connections for connection headspace oven TO 7280 - titration vessel TZ 1754/gas flow meter
TZ 3994	285227930	Fittings set drying bottle for TM 235 TO, 2 x fittings and 2 x O-ring
TZ 3997	285227960	Tube set complete for connection headspace oven TO 7280 - TM 235 TO
TZ 1632	285227990	Dosing tip made out of glass for titration vessel TZ 1754