Skip to Content
MilliporeSigma
  • Possibilities and limitations of signal summing for an immunosuppressant LC-MS/MS method.

Possibilities and limitations of signal summing for an immunosuppressant LC-MS/MS method.

Analytical and bioanalytical chemistry (2015-06-15)
Steven Pauwels, Ivo Jans, Nele Peersman, Jaak Billen, Dirk Vanderschueren, Koen Desmet, Pieter Vermeersch
ABSTRACT

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is the method of choice for quantifying small molecules in research and clinical setting. Although there is a large toolkit to increase quantification levels for LC-MS/MS, these techniques are sometimes insufficient to attain the needed limits of quantification (LOQs) or the method becomes too impractical for routine use. We examined the possibilities and limitations of signal summing, an under-utilized, easy-to-apply practice to increase LOQs for an immunosuppressant LC-MS/MS method. The limits of signal summing for everolimus were tested by running samples of everolimus at three concentrations in triplicate programming, increasing amounts of identical transitions in a constant cycle time up to the maximum number the software permitted to sum. The increase in peak area and the signal-to-noise ratio were determined. The effect on imprecision of peak areas and response ratios was evaluated by injection of a low concentration of everolimus tenfold using respectively one and five identical transitions, retaining an identical ion counting time. We compared the imprecision, LOQ, and recovery for our routine everolimus method (using one transition for everolimus and one for d3-everolimus) and an adapted method summing three identical transitions for everolimus (and one for d3-everolimus). The increase in signal was close to the theoretically expected one with a larger experimental spread for everolimus once more than five transitions were used. There was no clear beneficial effect of summing on imprecision. The adapted everolimus method showed a lower LOQ, but comparable imprecision and recovery as the routine method. Quantification levels can be improved by signal summing. No clear effect on imprecision was observed.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Acetonitrile solution, contains 0.05 % (w/v) ammonium formate, 5 % (v/v) water, 0.1 % (v/v) formic acid, suitable for HPLC
Pricing and availability is not currently available.
Sigma-Aldrich
Acetonitrile solution, contains 10.0% acetone, 0.05% formic acid, 40.0% 2-propanol
Pricing and availability is not currently available.
Sigma-Aldrich
Ammonium acetate, 99.999% trace metals basis
Pricing and availability is not currently available.
Sigma-Aldrich
Ammonium acetate solution, 50 % (w/v), for copper determination
Pricing and availability is not currently available.
Sigma-Aldrich
Ammonium acetate, BioXtra, ≥98%
Pricing and availability is not currently available.
Sigma-Aldrich
Ammonium acetate solution, for molecular biology, 7.5 M
Pricing and availability is not currently available.
Sigma-Aldrich
Ammonium acetate, reagent grade, ≥98%
Pricing and availability is not currently available.
Sigma-Aldrich
Methanol, NMR reference standard
Pricing and availability is not currently available.
Sigma-Aldrich
Ammonium acetate, for molecular biology, ≥98%
Pricing and availability is not currently available.
Sigma-Aldrich
Acetonitrile solution, contains 0.1 % (v/v) trifluoroacetic acid, suitable for HPLC
Pricing and availability is not currently available.
Sigma-Aldrich
Methanol, HPLC Plus, ≥99.9%, poly-coated bottles
Pricing and availability is not currently available.
Sigma-Aldrich
Acetonitrile solution, contains 0.05 % (v/v) trifluoroacetic acid
Pricing and availability is not currently available.
Sigma-Aldrich
Methanol, SAJ first grade, ≥99.5%
Pricing and availability is not currently available.
Sigma-Aldrich
Methanol, JIS 300, ≥99.8%, for residue analysis
Pricing and availability is not currently available.
Sigma-Aldrich
Methanol, SAJ special grade
Pricing and availability is not currently available.
Sigma-Aldrich
Methanol, suitable for HPLC
Pricing and availability is not currently available.
Sigma-Aldrich
Methanol, JIS special grade, ≥99.8%
Pricing and availability is not currently available.
Sigma-Aldrich
Methanol, suitable for HPLC, gradient grade, 99.93%
Pricing and availability is not currently available.
Sigma-Aldrich
Methanol, anhydrous, 99.8%
Pricing and availability is not currently available.
Sigma-Aldrich
Acetonitrile solution, contains 0.1 % (v/v) formic acid, suitable for HPLC
Pricing and availability is not currently available.
Sigma-Aldrich
Acetonitrile, anhydrous, 99.8%
Pricing and availability is not currently available.
Sigma-Aldrich
Acetonitrile, ≥99.5%, ACS reagent
Pricing and availability is not currently available.
Supelco
Acetonitrile, HPLC grade, ≥99.93%
Pricing and availability is not currently available.
Sigma-Aldrich
Acetonitrile, HPLC Plus, ≥99.9%, poly-coated bottles
Pricing and availability is not currently available.
Sigma-Aldrich
Acetonitrile, for residue analysis, JIS 5000
Pricing and availability is not currently available.
Sigma-Aldrich
Acetonitrile, for chromatography
Pricing and availability is not currently available.
Sigma-Aldrich
Acetonitrile, JIS special grade, ≥99.5%
Pricing and availability is not currently available.
Sigma-Aldrich
Acetonitrile, ≥99.8%, suitable for HPLC
Pricing and availability is not currently available.
Sigma-Aldrich
Acetonitrile, SAJ first grade, ≥99.0%
Pricing and availability is not currently available.
Sigma-Aldrich
Formic acid, JIS special grade, ≥98.0%
Pricing and availability is not currently available.