WO200201220-A2  L E RIPLEY ET AL: "Improved alkalimetric monitoring for anaerobic digestion of high-strength wastes" JOURNAL WPCF, vol. 58, May 1986 (1986-05), pages 406-411, XP002902103;  DATABASE DIALOG INF. SERVICES [Online] File 103, Energy SciTec, February 1994 (1994-02) S. TORP ET AL : "Development of an on-line gas chromatographic measuring system for volatile fatty acids (VFA) determination and automated regulation of biogas reactors with regard to specific VF acids" XP002902101;  J W PAUL ET AL: "Rapid-extraction and analysis of volatile fatty acids in soil" COMMUN. IN SOIL SCI. PLANT ANAL., vol. 20, no. 1,2, 1989, pages 85-94, XP002902102EP1307735-B1  DATABASE DIALOG INF. SERVICES [Online] File 103, Energy SciTec, February 1994 (1994-02) S. TORP ET AL : "Development of an on-line gas chromatographic measuring system for volatile fatty acids (VFA) determination and automated regulation of biogas reactors with regard to specific VF acids" XP002902101;  J W PAUL ET AL: "Rapid-extraction and analysis of volatile fatty acids in soil" COMMUN. IN SOIL SCI. PLANT ANAL., vol. 20, no. 1,2, 1989, pages 85-94, XP002902102;  L E RIPLEY ET AL: "Improved alkalimetric monitoring for anaerobic digestion of high-strength wastes" JOURNAL WPCF, vol. 58, May 1986 (1986-05), pages 406-411, XP002902103WO200201220-A3  DATABASE DIALOG INF. SERVICES [Online] File 103, Energy SciTec, February 1994 (1994-02) S. TORP ET AL : "Development of an on-line gas chromatographic measuring system for volatile fatty acids (VFA) determination and automated regulation of biogas reactors with regard to specific VF acids" XP002902101;  J W PAUL ET AL: "Rapid-extraction and analysis of volatile fatty acids in soil" COMMUN. IN SOIL SCI. PLANT ANAL., vol. 20, no. 1,2, 1989, pages 85-94, XP002902102;  L E RIPLEY ET AL: "Improved alkalimetric monitoring for anaerobic digestion of high-strength wastes" JOURNAL WPCF, vol. 58, May 1986 (1986-05), pages 406-411, XP002902103;  DATABASE DIALOG INF. SERVICES February 1994 (1994-02-01), S. TORP ET AL: "Development of an on-line gas chromatographic measuring system for volatile fatty acids (VFA) determination and automated regulation of biogas reactors with regard to specific VF acids", XP002902101,relevantClaims[1-5,9-19,24-26],relevantPassages[&lt;pp&gt;A&lt;/pp&gt;Dialog accession no. 03698706,DK-94-001433,NEI-DK-1584,(36p)];  J W PAUL ET AL: "Rapid-extraction and analysis of volatile fatty acids in soil", COMMUN. IN SOIL SCI. PLANT ANAL., vol. 20, no. 1,2, 1989, pages 85 - 94, XP002902102,relevantClaims[1-5,14-17],relevantPassages[&lt;pp&gt;86&lt;/pp&gt;&lt;ppl&gt;88&lt;/ppl&gt;];  L E RIPLEY ET AL: "Improved alkalimetric monitoring for anaerobic digestion of high-strength wastes", JOURNAL WPCF, vol. 58, May 1986 (1986-05-01), pages 406 - 411, XP002902103,relevantClaims[1-26],relevantPassages[&lt;pp&gt;1&lt;/pp&gt;&lt;ppl&gt;2&lt;/ppl&gt;&lt;linel&gt;12&lt;/linel&gt;]