German term (edited): substanzähnliche Quantifizierung

Using alpha-pinene as the reference.

http://www.multigips.de/wp-content/uploads/2017/01/2012_05_a...
2) Indentifizierung und Quantifizierung mittels HPLC/DAD-Referenzsubstanz.
4) Identifizierung mittels GC/MS ueber Spektrenbibliothek, substanzaehnliche Quantifizierung.
5) Identifizierung mittels GC/MS ueber Spektrenbibliothek, Quantifizierung als Toluolaequivalent.
8) Identifizierung und Quantifizierung mittels Referenzsubstanz, GC/MS.

http://www.gerstelus.com/media/1076/1997-02_tds-g-biogenic-e...
Figure 5. Comparison of liquid injection and thermal desorption methods. Compounds are first normalized to their molar mass and then normalized to the monoterpene α-pinene internal standard.

https://onlinelibrary.wiley.com/doi/full/10.1046/j.1432-1033...
The esters formed were extracted with 250 µL pentane containing 5 µL·L−1 α‐pinene as internal standard, vortexed for 1 min and 1 µL of the pentanic phase was injected into the GC for analysis [14].

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Note added at 1 day 19 hrs (2018-06-07 09:40:27 GMT)
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After more digging, I think this phrase means that the α-pinene, as a similar compound to the analyte, was used as the reference standard during the quantitative determination. A brief way of expressing this could be "quantitated using α-pinene as surrogate standard."

http://www.freepatentsonline.com/EP2111959A2.html
Die Quantifizierung erfolgt über eine lineare Mehrpunktkalibrierung der entsprechenden Referenzsubstanzen sowie dem relativen Responsefaktor des internen Standards (Toluold8). Verbindungen, für die kein entsprechender Standard verfügbar war, wurden substanzähnlich quantifiziert (vgl. Tabelle 2)...
Tabelle 2: Standards zur Quantifizierung von Nebenkomponenten
Verbindung // Standard
Terpene // α-Pinen, Toluol

https://www.cdc.gov/niosh/nioshtic-2/20030298.html
Evaluation of surrogate standards for GC/MS quantitation of asphalt fume condensate.

https://aerosolschool.web.psi.ch/gothenburg_2008/Participant...
Slide 12
α-pinene (surrogate for monoterpenes)