internal standard


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internal standard

[in′tərn·əl ′stan·dərd]
(spectroscopy)
The principal line in spectrum analysis by the logarithmic sector method, a quantitative spectroscopy procedure.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
[2] Nonstandard abbreviations: DALY, disability-adjusted life years; A/IS, area drug to internal standard.
Internal standard, tyrosine (100 [micro]L), was added to each standard mixture or urine (100 [micro]L) and vortex mixed for 30 seconds followed by centrifugation (5 min at 3000 rpm); the supernatant (20 [micro]L) was injected.
20 [micro]L blood sample and 100 [micro]L acetonitrile (containing 20 ng/mL internal standard gelsenicine) were added in a 1.5 mL Eppendorf tube, mixed using a vortex mixer for 1.0 min, and centrifuged at 13,000 rpm for 10 min at 4[degrees]C.
Key words: calibration; chromatography; internal standards; quantitation; quantitative analysis; response factor.
By using the same pipette used for the calibration solution, 2 ml of the internal standard solution was mixed and diluted to 100 ml in other volumetric flask.
The selection of internal standard for LC-MS/MS method was different for HPLC-UV method.
Slightly different sample preparation conditions were used for SIL versus SILAC internal standard methods prior to LC-MS analysis as shown in Figure 1.
The DC for each blend, polymerized and unpolymerized, was determined by the ratio of the absorbance peak corresponding to the aliphatic carbon-carbon double bond (1637 [cm.sup.-1] peak height) with that of the internal standard (1715, 1608, and 1582 [cm.sup.-1] peak height), according to methods described in a previous study.
For example, it says Toyota never produced a document showing the company's internal standard for roof strength was tougher than the federal requirement, CBS News reported.

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