The first address for FOS / TAC analysis

The new TitroLine® 5000

The new titrator TitroLine® 5000 makes your job easier. TitroLine® is the device of choice for FOS / TAC titrations. With innovative features for easy handling – combined with high accuracy.

  • With standard method for FOS / TAC-titration
  • No complicated parameter setting
  • Complete with robust and low-maintenance pH electrode
  • With high-contrast TFT display, which can be perfectly read even from the side
  • Storage of measurement results via USB port (PDF or CSV format) possible
  • Also suitable for the pH-measurement


FOS / TAC – an important parameter for fermentation processes in biogas plants

An important parameter for the assessment of the fermentation process of modern biogas plants is the so called FOS / TAC value. The TAC (= Totales inorganic carbonate, also known as lime buffer) obtained by the titration of 20 ml of a centrifuged fermenter sample to pH 5.0 with 0.05 mol / l sulfuric acid. The FOS (= Volatile Organic acids) is determined by titration of the same sample to pH 4.4. The two values obtained in ml are used in two empirically derived formulas:


TAC = ml H2SO4 to pH 5.0 × 250

FOS = (ml H2SO4 from pH 5.0 to pH 4.4 × 1.66 – 0.15) × 500

Also another sample volume than 20 ml can be considered. From the values of both results of the FOS / TAC value is calculated. This method with all parameters and calculation formulas is stored as a standard method to TitroLine® 5000 and can be used directly.

Ordering Information

Type no.  Article no.  Description
5000-M2/50 285225790 TL 5000 basic unit with ready-mounted 50 ml dosing TZ 3160 with hoses, fittings and titration, magnetic stirrer TM 50, controller TZ 3880, titration clamp Z 305 and stand rod TZ 1748, including low-maintenance pH combination electrode A 7780 NTC30 DIN N and buffer set.