Determination of Drug-to-Antibody
Ratio for Antibody-Drug Conjugates
Puriﬁed from Serum
Using Automated Afﬁnity Puriﬁcation, LC/MS analysis,
and Novel DAR Calculation Software

Application Note

Authors

Introduction

Jing Chen, Michael Bovee, andAntibody-drug conjugates (ADCs) are an emerging class of biotherapeutics designed toprovide targeted drug delivery by linking drugs to monoclonal antibodies. Unlike small
molecule drugs, ADCs are not single molecular entities, but are instead a heterogeneous
population of antibodies that vary by the number of drugs on each antibody and byvariability in post-translational modiﬁcations. The drug-to-antibody ratio (DAR) is theaverage number of drugs coupled to an ADC. The DAR is a critical quality attribute of an
ADC that is optimized and closely monitored during ADC development, as it can affectefﬁcacy and toxicity1,2.

Steve Murphy
Agilent Technologies, Inc.

The DAR for an ADC can change over time in circulation due to drug release1,3.
Therefore, it is critical to have a robust solution for ADC DAR determination of samples
from pharmacokinetic (PK) studies. To determine ADC DAR, ﬁrst the ADC must be
puriﬁed from the serum, then analyzed by LC/MS. The sample preparation and data
analysis in this workﬂow are typically labor intensive and, therefore, susceptible tovariability and human error.
This Application Note presents a solution for determining the DAR of ADCs in serum
samples that uses the Agilent AssayMAP Bravo Platform to automate ADC afﬁnity
puriﬁcation, an Agilent 1290 Inﬁnity UHPLC coupled to an Agilent 6550 Q-TOF mass
spectrometer to acquire accurate intact protein mass data, and Agilent MassHunter
BioConﬁrm and DAR Calculator software to determine the ADC mass and DAR. This
workﬂow decreases the labor, variability, and the probability of human error associatedwith ADC DAR determination, while simultaneously allowing the number of samples tobe scaled with minimal additional effort.

Experimental
Materials
Recombinant human HER2 extracellulardomain (ECD) was purchased from
ACRO Biosystems (Newark, DE). EZ-Link
Sulfo-NHS-LC-Biotin and Pierce Biotin
Quantitation Kit were purchased from
Thermo Fisher Scientiﬁc (Grand Island,
NY). Rat serum was purchased from
BioreclamationIVT (Hicksville, NY).
AssayMAP Streptavidin cartridges (SA-W)
were from Agilent Technologies, Inc.
(Santa Clara, CA). All other chemicals
were from Sigma-Aldrich (St. Louis, MO).

Biotinylation and immobilization of
ADC antigen
HER2 ECD was biotinylated using
the EZ-Link Sulfo-NHS-LC biotin kit
per manufacturer’s instructions. The
molar ratio of biotin to HER2 ECD wasdetermined to be 9.0 by the Pierce Biotin
Quantitation Kit per manufacturer’s
instructions. Two micrograms of
biotinylated HER2 ECD were immobilizedon each AssayMAP SA-W cartridge using
the Agilent AssayMAP Bravo controlled
by the Immobilization application. Brieﬂy,
SA-W cartridges (microchromatography
cartridges packed with approximately
5 µL of packed resin to which streptavidin
was covalently coupled) were primed
and equilibrated with 1 % formic acid,then washed with HEPES buffer (10 mM
HEPES, 150 mM NaCl, pH 7.4) using
the Immobilization application default
settings for Prime, Equilibrate, andInternal Cartridge Wash 1. All other steps
in the Immobilization application wereturned off. Priming and equilibrating with

1 % formic acid purges the entrained
air from the cartridges, and acts as astringent wash to remove streptavidin
monomers that dissociate from thesolid support in the low pH condition
experienced in the ﬁnal elution. The
wash step prepares the cartridges tobind the biotinylated antigen. Next, each
SA-W cartridge was loaded with 2 µg of
biotinylated antigen in a 100 µL HEPES
buffer at a ﬂow rate of 5 µL/min followed
by one wash with HEPES buffer using
the AssayMAP Bravo controlled by the
Immobilization application. In this case,the default settings for the Sample Loadand Internal Cartridge Wash 1 were used,
and all other steps of the application
were turned off. Following this procedure,
2 µg of biotinylated ADC antigen were
coupled to each SA-W cartridge thereby
generating ADC afﬁnity cartridges.

ADC afﬁnity puriﬁcation
Commercially obtained lyophilized ADC
was reconstituted in deionized (DI) waterto 1 mg/mL, aliquoted, and stored at–80 °C until used. ADC was spiked into
rat serum and serially diluted to prepare
ADC concentrations of 20, 10, 5, 2.5, 1.25,
and 0.625 µg/mL. Rat serum without ADC
spiked was also included as a control.
These samples were further diluted 1:1
with HEPES buffer immediately before
loading the samples on ADC afﬁnity
cartridges. Afﬁnity puriﬁcation was
performed using the AssayMAP Bravo
controlled by the Afﬁnity Puriﬁcation
application. Brieﬂy, 100 µL of the diluted
rat serum containing ADC was loaded
onto each ADC afﬁnity cartridge (n = 4 foreach ADC concentration) at a ﬂow rate of2

3 µL/min, followed by four 50 µL washes(HEPES buffer, 1 M NaCl in HEPES buffer,
0.003 % formic acid, and water) at a ﬂow
rate of 10 µL/min. Finally, the puriﬁed
ADC was eluted with 15 µL of 1 % formic
acid per cartridge into an existing volumeof 15 µL 0.5 % ammonium hydroxide toneutralize the puriﬁed ADC.

LC/MS analysis
LC/MS analyses were conducted onan Agilent iFunnel Accurate Mass 6550
Q-TOF (Santa Clara, CA) equipped witha Dual Agilent Jet Stream ESI source
coupled with an Agilent 1290 Inﬁnity
UHPLC system (Santa Clara, CA). Table 1
and Table 2 list the LC/MS parametersused. Three microliters (1/10th of thetotal sample volume) of the ADC puriﬁed
from all the serum samples were injected
for MS only analysis; additionally, 10 µL(1/3rd of the total sample volume) of
the ADC puriﬁed from serum samples
containing ADC concentrations of 2.5,
1.25, and 0.625 µg/mL were injected
for MS only analysis. One hundred
nanograms of commercially obtained ADC
were injected (n = 4) as a control.

Data analysis
Raw data ﬁles were analyzed by
Agilent MassHunter BioConﬁrm
software. Spectra were extracted andaveraged between 2.2 and 3.2 minutes,
and deconvoluted. The DAR of ADC
and the percentage of ADC with eachdrug load were calculated using theAgilent MassHunter DAR Calculator andthe deconvoluted spectra. Table 3 shows
the deconvolution parameters.

Table 1. Liquid chromatography parameters.
Parameter

Agilent 1290 Inﬁnity UHPLC System

ColumnAgilent PLRP-S 1000Å 8 µm 150 × 2.1 mm (PL1912-3802)

Sample thermostat

5 °C

Mobile phase A

0.1 % Formic acid in water

Mobile phase B

0.1 % Formic acid in acetonitrile

Gradient (segmented)

Time (min)

%B

0–0.5

25

0.5–1.5

25–35.5

1.5–3.5

35.5

Stop time

3.5–5.0

35.5–50

5.0–5.550–25

5.5–7.525

7.5 minutes

Column temperature

80 °C

Flow rate

0.4 mL/min

Table 2. Mass spectrometer parameters.
Parameter

Agilent 6550 Q-TOF Mass Spectrometer

Ion mode

Positive ion mode

SourceAgilent Dual Jet Stream

Drying gas temperature

225 °C

Drying gas ﬂow

14 L/minSheath gas temperature

325 °C

Sheath gas ﬂow

12 L/min

Nebulizer

40 psiCapillary voltage

4,500 V

Nozzle1,500 V

Fragmentor voltage

250 V

Oct RF Vpp

750 V

Acquisition parameters
MS modeHigh (10,000 m/z) mass range,
Extended mass range (2 GHz),MS only mode,
Mass range 1,000–4,500 m/z.

Table 3. MassHunter BioConﬁrm parameters.
Parameter

Agilent MassHunter BioConﬁrm Deconvolute (MS): Protein

Deconvolution algorithm

Maximum entropy

Deconvolution settings

Mass range: 140–160 KDa
Mass step: 1.0 Da

Use limited m/z range

2,000–4,500 m/z

Baseline

Subtract baseline
Baseline factor 3.50

AdductProtonIsotope width

Automatic

3

Results and Discussion
A solution for determining the DAR
of ADCs from serum samples wasdeveloped. This solution includes
automated afﬁnity puriﬁcation of ADCs
from serum using ADC afﬁnity cartridges
on the AssayMAP Bravo, acquisitionof MS spectra of intact ADCs using a1290 Inﬁnity UHPLC and a 6550 Q-TOF
mass spectrometer, deconvolution of
MS spectra using Agilent MassHunter
BioConﬁrm, and calculation of DAR using
Agilent MassHunter DAR Calculator(Figure 1).
The ﬁrst step of this workﬂow is theautomated puriﬁcation of ADC fromserum. To accomplish this step, custom
AssayMAP afﬁnity cartridges weregenerated by immobilizing biotinylated
ADC antigen on AssayMAP SA-W
cartridges using the AssayMAP Bravo
controlled by the Immobilization
application, which is speciﬁcallydesigned to generate custom afﬁnity
cartridges. Two micrograms of antigen
were immobilized per cartridge, which
represents approximately a 4-foldmolar excess of antigen compared tothe maximum amount of antibody tobe puriﬁed in this Application Note.
Optimization studies demonstrated thata 4-fold molar excess was sufﬁcient for
efﬁcient capture of the target ADC (datanot shown), at the ﬂow rate used in thisApplication Note. The ﬂow rate and levelof molar excess are related, and both canbe altered depending on the experimental
design. It should be noted that theamount of antigen used was not limitedby the capacity of the SA-W, which isapproximately 75 µg for this particularantigen, but was instead chosen
to minimize the amount of antigen
consumed by these experiments.

SA-W

SA-W

Sample preparation

LC/MS

DAR calculation

Figure 1. ADC DAR determination workﬂow.

Commercially obtained ADC was spiked
into rat serum at a concentration of
20 µg/mL, then afﬁnity puriﬁed using
the ADC afﬁnity cartridges and the
AssayMAP Bravo controlled by theAfﬁnity Puriﬁcation application. One
hundred nanograms of the commerciallyobtained ADC (Figure 2A) and 100 ng
of ADC afﬁnity puriﬁed from the serum
samples (Figure 2B), assuming 100%
recovery, were analyzed by LC/MS. The
major peak, observed between 2.2 and3.2 minutes, represents the elution of
the ADC. Minor additional peaks wereobserved in the afﬁnity puriﬁed ADC
between 1 and 1.5 minutes, representing
residual salts and between 4.7 and5.5 minutes, representing copuriﬁedproteins from rat serum with the massenvelope centered around 1,500 m/z.
These residual copuriﬁed proteins do
not interfere with the ionization of the4

ADC as they are completely separated
by the ﬁne-tuned LC gradient. Figures 2C
and 2D show that the extracted spectra
over the ADC elution window are nearly
identical. After deconvolution, sevenpeak groups representing DAR values of
0–7 were observed in the deconvoluted
mass spectra of both the commerciallyobtained ADC (Figure 2E) and the afﬁnity
puriﬁed ADC (Figure 2F), with four major
peaks in each peak group, representing
the ADC with various glycoforms (thatis, G0F/G0F, G0F/G1F, G1F/G1F or
G0F/G2F, and G1F/G2F). MassHunter
DAR Calculator was used to calculate
DAR using areas under the seven peakgroups. Similar DARs were calculated(DAR = 3.5) for both conditions. These
results demonstrate the high recovery
and high purity that can be achieved
with automated ADC puriﬁcation on the
AssayMAP Bravo Platform.

×10 8
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0

A

2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0

B

CountsCounts

×10 8

0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0
Acquisition time (min)0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0
Acquisition time (min)

×10 3
4.5

C

4.0

3.0

CountsCounts

3.5

2.5
2.0
1.5
1.0
0.5
0
2,200

2,600

×10 4
2.0
E
1.8

3,000
3,400
3,800
Mass-to-charge (m/z)

×10 3
3.6
3.4
3.2
3.0
2.8
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0

D

4,200

2,200

2,600

DAR 2

DAR 3

F

1.6

Avg. DAR = 3.5

DAR 4

DAR 2

1.2

DAR 5
CountsCountsAvg. DAR = 3.5
DAR 4

1.4

1.6
1.2
DAR 1
DAR 6

0.8

1.0

DAR 5

0.8

DAR 1
DAR 6

0.6

0.6
DAR 7

0.4
0.2

4,200

×10 4
DAR 3

1.4
1.0

3,000
3,400
3,800
Mass-to-charge (m/z)

DAR 0

0.4

DAR 7

0.2

0

DAR 0

0
148,000

149,500

151,000
152,500
154,000
Deconvoluted mass (Da)

155,500

148,000

149,500

151,000
152,500
154,000
Deconvoluted mass (Da)

155,500

Figure 2. Representative total ion chromatograms (TICs), extracted spectra, and deconvoluted spectra from commercially obtained ADC and the
afﬁnity puriﬁed ADC. A) TIC of commercially obtained ADC. B) TIC of afﬁnity puriﬁed ADC. C) Extracted spectra of commercially obtained ADC.
D) Extracted spectra of afﬁnity puriﬁed ADC. E) Deconvoluted spectra with DAR calculation of the commercially obtained ADC. F) Deconvoluted
spectra with DAR calculation of afﬁnity puriﬁed ADC.

5

20 µg/mL, CV = 3.44 %10 µg/mL, CV = 6.90 %5 µg/mL, CV = 8.61 %2.5 µg/mL, CV = 3.33 %1.25 µg/mL, CV = 10.85 %0.625 µg/mL, CV = 15.51 %0 µg/mL, CV = 7.54 %

×108
2.0

EIC: m/z
2,000–4,500

1.8
1.6
1.4
CountsTo assess the suitability of the workﬂow
for PK studies, the commercially obtained
ADC was spiked into and serially diluted
in rat serum to 20, 10, 5, 2.5, 1.25, and
0.625 µg/mL and puriﬁed as describedabove. Rat serum samples containing
no ADC were also puriﬁed as a control.
The amount of ADC in the serum sample
loaded onto each cartridge was 1,000,
500, 250, 125, 62.5, 31.25, and 0 ng,
respectively. Ten percent of the eluate
was injected for mass spectrometry
analysis for each afﬁnity puriﬁed sample,
corresponding to 100, 50, 25, 12.5,
6.25, 3.125, and 0 ng ADC on-column
assuming 100 % recovery. Figure 3 showsthe extracted ion chromatograph (EIC)
over the mass envelope of the ADC(2,000–4,500 m/z). Peaks between 2.2
and 3.2 minutes were integrated andthe coefﬁcients of variation (CVs) were
calculated for each ADC concentration.
Excellent reproducibility was achieved
with CVs less than 10 % for puriﬁed ADCs
from serum samples with concentrations
higher than 1.25 µg/mL. Note that the EICof afﬁnity puriﬁed serum control (no ADC
spiked) are essentially ﬂat, demonstrating
the absence of copuriﬁed proteins in the
ADC elution window. This speciﬁcity wasachieved with the low nonspeciﬁc bindingof the SA-W cartridge, the high speciﬁcityof the ADC for the antigen, and theﬁne-tuned wash conditions. No detergent
was needed for removal of copuriﬁedproteins.

1.2
1.0
0.8
0.6
0.4
0.2
0
1.6 1.7 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 4.0 4.1
Acquisition time (min)Figure 3. Extracted ion chromatographs (EIC) of afﬁnity puriﬁed ADC at various serum concentrations.
Fifty microliters of rat serum containing 20, 10, 5, 2.5, 1.25, 0.625 and 0 µg/mL ADC (n = 4 for eachconcentration) was afﬁnity puriﬁed with ADC afﬁnity cartridges using Agilent AssayMAP Bravo. Tenpercent of the puriﬁed ADC from serum samples was injected for mass spectrometry analysis for eachafﬁnity puriﬁed sample. EICs (2,000–4,500 m/z) were extracted. Peaks between 2.2 and 3.2 minutes were
integrated and coefﬁcients of variation (CV) were calculated for the samples at each ADC concentration.

Figure 4 shows the deconvoluted
spectra and DAR of afﬁnity puriﬁed ADC
from rat serum samples with 20, 10, 5,
2.5, 1.25, and 0.625 µg/mL ADC. The
signal-to-noise ratio (S/N) decreases as
the amount of ADC analyzed decreases
so 33 % of the puriﬁed ADC from serum
samples with ADC concentrations of 2.5,
1.25, and 0.625 µg/mL were analyzed
compared to 10 % of the puriﬁed
ADC from serum samples with ADC
concentrations of 20, 10, and 5 µg/mL.
This allowed higher quality deconvoluted
spectra to be obtained from the samples
with lower ADC concentrations.
Comparable deconvoluted spectra
and DARs were obtained for all ADC
concentrations tested (Figure 4, Table 4).
The percentages of ADC with various
drug loads (D0-D7) were comparable
for ADCs puriﬁed from serum samples

6

with ADC concentrations of 20, 10, 5 and2.5 µg/mL, and closely resemble those of
the commercially obtained ADC directly
injected for MS analysis. The percentagesof the various drug loads were less wellaligned to the commercially obtained
ADC for ADCs puriﬁed from serum
samples with ADC concentrationsof 1.25 and 0.625 µg/mL (Table 4,
Figure 5). To improve spectra quality anddecrease detection/quantitation limitof the workﬂow, a higher percentage ofthe eluate may be injected for LC/MS
analysis. Additionally, deglycosylation
may be performed before elution of the
ADC to simplify spectra, and to increase
the signal. These results demonstratethat the presented workﬂow canreproducibly determine DAR and thepercentages of ADC with different drugloads at low serum ADC concentrations.

×10 4

1.4
DAR 2

1.2
CountsC ADC = 20 µg/mL
Avg. DAR = 3.5

DAR 4

1.0

DAR 5

0.8

DAR 1

0.6

0.2

DAR 7

151,000
152,500
154,000
Deconvoluted mass (Da)

DAR 1

3

DAR 6
DAR 7

DAR 0

148,000

155,500
×10 2
3.5

DAR 3
C ADC = 10 µg/mL
Avg. DAR = 3.5

DAR 4

149,500

151,000
152,500
Deconvoluted mass (Da)E

155,500

C ADC = 1.25 µg/mL
Avg. DAR = 3.5

DAR 4

DAR 2

DAR 2

154,000

DAR 3

3.0
2.5

DAR 5

CountsCounts

B

DAR 1
DAR 6

2.0

DAR 1

DAR 5

1.5

DAR 6

1.0

DAR 7

DAR 0

DAR 7

DAR 0

0.5
0

148,000

149,500

151,000
152,500
154,000
Deconvoluted mass (Da)148,000

155,500

×10 2

×10 2
1.4

DAR 3

C

4.8

DAR 4

4.2

C ADC = 5 µg/mL
Avg. DAR = 3.5

2.4
DAR 6

1.8

F

1.2

DAR 4

DAR 0

0

154,000

155,500

C ADC = 0.625 µg/mL
Avg. DAR = 3.5

DAR 2
DAR 5

0.8

DAR 1

0.6
0.4

DAR 7

151,000
152,500
Deconvoluted mass (Da)
DAR 3

1.0
DAR 5

CountsDAR 1

3.0

149,500

1.2

DAR 2

3.6
CountsDAR 5

4

0
149,500

×10 4

0.6

DAR 4

DAR 2

5

1

DAR 0
148,000

5.4

C ADC = 2.5 µg/mL
Avg. DAR = 3.5

2

0

1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0

DAR 3

6

DAR 6

0.4

D

7

Counts

1.6

×10 2
8

DAR 3

A

DAR 6 DAR 7

DAR 0

0.2
0

148,000

149,500

151,000
152,500
154,000
Deconvoluted mass (Da)148,000

155,500

149,500

151,000
152,500
154,000
Deconvoluted mass (Da)

155,500

Figure 4. Representative deconvoluted spectra and DAR of afﬁnity puriﬁed ADC from rat serum. Fifty microliters of rat serum containing 20, 10,5, 2.5, 1.25, 0.625, and 0 µg/mL ADC (n = 4 for each concentration) was afﬁnity puriﬁed with ADC afﬁnity cartridges using Agilent AssayMAP
Bravo. Ten percent of the puriﬁed ADC from serum samples containing ADC at 20 µg/mL (A), 10 µg/mL (B), and 5 µg/mL (C) were injected for MS
analysis; 33 % of the puriﬁed ADC from serum samples containing ADC at 2.5 µg/mL (D), 1.25 µg/mL (E), and 0.625 µg/mL (F) were injected for
MS analysis. CADC: Concentration of ADC in rat serum.

7

Table 4. The DAR and the percentage of ADC for each drug load.
Percentage of ADC for each drug load (%)
Sample

DAR

DAR 0

DAR 1

DAR 2

DAR 3

DAR 4

DAR 5

DAR 6

DAR 7

Commercially obtained (n = 4)3.50±0.02

2.11±0.75

9.9±1.08

17.35±0.33

22.82±1.69

19.88±1.81

15.35±0.47

7.97±0.93

4.65±0.77

Afﬁnity puriﬁed from 20 µg/mL
serum samples (n = 4)

3.49±0.02

2.4±0.68

9.45±1.05

17.32±0.25

23.32±1.45

20.17±1.63

14.97±0.59

7.58±0.69

4.8±0.88

Afﬁnity puriﬁed from 10 µg/mL
serum samples (n = 4)

3.46±0.02

2.54±0.19

9.72±0.24

17.38±0.18

23.87±0.47

19.73±0.13

14.36±0.13

7.47±0.24

4.95±0.38

Afﬁnity puriﬁed from 5 µg/mL
serum samples (n = 4)

3.49±0.03

3.47±0.21

9.67±0.74

16.6±0.16

22.3±0.1

19.83±1.08

14.41±0.21

8.49±0.26

5.24±0.74

Afﬁnity puriﬁed 2.5 µg/mL
serum samples (n = 4)3.43±0.06

3.08±0.26

9.94±0.22

17.83±0.53

23.21±0.59

19.55±0.18

13.64±0.23

8.01±0.65

4.73±0.54

Afﬁnity puriﬁed 1.25 µg/mL
serum samples (n = 4)

3.4±0.1

4.43±0.22

11.31±1.68

17.96±0.89

20.73±0.65

18.17±0.94

12.55±1.17

9.08±0.55.78±0.66

Afﬁnity puriﬁed 0.625 µg/mL
serum samples (n = 4)

3.48±0.08

6.49±0.66

10.95±1.45

16.43±0.8

17.9±0.98

16.61±0.49

12.67±1.29

11.91±0.71

7.05±0.43

Commercially available
Afﬁnity puriﬁed 20 mg/mL
Afﬁnity puriﬁed 10 mg/mL
Afﬁnity puriﬁed 5 mg/mL
Afﬁnity puriﬁed 2.5 mg/mL
Afﬁnity puriﬁed 1.25 mg/mL
Afﬁnity puriﬁed 0.625 mg/mL

25% of total ADC

20

15

10

5

0
D0

D1

D2

D3
D4
Drug load

D5

D6

D7

Figure 5. Percentage of ADC for each drug load.

8

Conclusions

References

Agilent provides a complete ADC DAR
determination solution that includes
automated afﬁnity puriﬁcation with
the Agilent AssayMAP Bravo, LC/MS
acquisition with the Agilent 1290 Inﬁnity
UHPLC and an Agilent 6550 Q-TOF,
deconvolution with Agilent MassHunter
BioConﬁrm software, and DAR
determination with Agilent MassHunter
DAR Calculator. This ADC DAR
determination solution:

1. Perez, H. L.; et al. Antibody-drug
conjugates: current status and future
directions. Drug Discovery Today 2014,19(7), 869-881.

•

Reduces manual labor, variability,
and the probability of human error•

Puriﬁes ADCs from serum withhigh yield and purity•

Generates high resolution spectra•

Provides easy DAR calculation

2. Beck, A.; et al. Cutting-edge mass
spectrometry methods for themulti-level structural characterizationof antibody-drug conjugates. Expert
Reviews of Proteomics 2016, 13:2,
157-183.
3. Xu, K.; et al. Characterization of
intact antibody-drug conjugatesfrom plasma/serum in vivo by
afﬁnity capture capillary liquid
chromatography-mass spectrometry.
Analytical Biochemistry 2011, 412,
56-66.

9

www.agilent.com/chem/bioconﬁrm
For Research Use Only. Not for use in diagnostic
procedures.
This information is subject to change without notice.
© Agilent Technologies, Inc., 2016
Published in the USA, March 30, 2016
5991-6621EN