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Access Agilent eNewsletter, August 2013

Detect virtually everything your LC separates – the Agilent 1290 Infinity Evaporative Light Scattering Detector

By Graham Cleaver
Agilent Business Development Manager

The Agilent 1290 Infinity Evaporative Light Scattering Detector (ELSD) and the Agilent 1260 Infinity Evaporative Light Scattering Detector are becoming well established as the detectors of choice for compounds with little or no UV chromophore. With sensitivity often as much as 100 times that of a refractive index detector and compatibility with solvent gradients, many pharmaceutical and food laboratories widely use ELSD. The unique features of the Agilent 1290 Infinity ELSD include:

  • Greater sensitivity by virtue of the blue laser light source; limits of detection are up to 20-fold better than the previous model.
  • Unique low temperature evaporation coupled with proprietary gas flow technology means that low molecular weight and semi volatile compounds are detected rather than destroyed.
  • Agilent ELSD Dimension Software that uses gas flow programming to ensure uniform compound response across even the steepest solvent gradients.
  • The heated nebulizer provides supercritical fluid (SFC) compatibility without modification.
  • Achievement of 0.1 to 5 mL/min operation without the need to split the flow or to change the nebulizer.
  • Compounds libraries that have been stored in dimethylsulfoxide (DMSO) can be accurately screened without extensive sample preparation prior to analysis.

In-depth information from library of Agilent technical and application notes

Since the launch of the new ELSD portfolio, we have released an ever-increasing number of technical and application notes, which demonstrates our commitment to your success with evaporative light scattering detection.

One Agilent Technical Note demonstrates the ease of transfer of an existing method from an Agilent 385 ELSD to an Agilent 1290 Infinity ELSD with an immediate 20-fold gain in sensitivity after just a small optimization step. (See Figure 1 and Table 1.) We used the measurement of lactose as an example because the determination of residual lactose in lactose-free dairy products is an important application.

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Figure 1. Injection of lactose on an Agilent 1290 Infinity ELSD under optimized gas flow settings; results show 20-fold sensitivity improvement over Agilent 385 ELSD.

 

Agilent 385 ELSD

Agilent 1290 Infinity ELSD

LOD (S/N) = 3

50 mg/L

2.5 mg/L

LOQ (S/N) = 10

100 mg/L

5 mg/L

R.T. RSD (%)

0.29

0.11

Area RSD (%)

3.68

3.51

Table 1. Comparison of limit of detection (LOD), limit of quantitation (LOQ) and relative standard deviation (RSD) of retention time (RT) and peak area for Agilent 385 ELSD and Agilent 1290 Infinity ELSD.

Optimize performance of the Agilent 1290 Infinity ELSD

In another Agilent Technical Note, we show how to achieve best performance of the Agilent 1290 Infinity ELSD. This note shows and explains the influence of various parameter settings on sensitivity and resolution. It is an invaluable reference to achieve the lowest limits of detection for your samples.

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Figure 2. Overlay of chromatograms of amino acids (0.1 mM) with various evaporator temperatures shows the importance of optimization.

40 °C

Compound

Signal (mV)

Noise (mV)

S/N

 

Valine

1.83

0.06

3.14

 

Leucine

1.83

0.06

3.24

 

Phenylalanine

2.50

0.06

4.45

50 °C

Compound

Signal (mV)

Noise (mV)

S/N

 

Valine

9.25

0.04

15.14

 

Leucine

4.75

0.04

8.52

 

Phenylalanine

11.01

0.04

17.91

Table 2. Dramatic signal-to-noise (S/N) improvement at 50°C: amino acids with two evaporator temperatures.

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Figure 3. Much easier analyte detection: removal of DMSO by increasing gas flow with no loss in acetanilide at 30 °C.

High throughput screening of samples stored in DMSO

An in-depth Agilent Application Note describes how you can use the Agilent 1290 Infinity Evaporative Light Scattering Detector for high throughput screening of drug candidates, to analyze samples from combinatorial libraries that are stored in the solvent dimethylsulfoxide (DMSO). Often compounds of interest may elute under or close to the solvent front, making them almost impossible to detect without removal of DMSO prior to analysis. By optimization of the gas flow, the ELSD removes the DMSO and saves analyst time.

Learn more and explore the possibilities

Watch our video that illustrates with some exciting graphics the complete ELSD process from nebulization through detection. A number of examples help to demonstrate and expand on the unique features of the Agilent 1290 Infinity ELSD, and to illustrate the wide range of configurations from UHPLC through SFC, LC/MS, and gel permeation chromatography (GPC).

Figure 1.

Injection of lactose on an Agilent 1290 Infinity ELSD under optimized gas flow settings; results show 20-fold sensitivity improvement over Agilent 385 ELSD.

Figure 2.

Overlay of chromatograms of amino acids (0.1 mM) with various evaporator temperatures shows the importance of optimization.

Figure 3.

Peak ID

  1. Adenosine monophosphate
  2. DMSO
  3. Acetaminophen
  1. Caffeine
  2. Acetanilide
  3. Phenacetin

Much easier analyte detection: removal of DMSO by increasing gas flow with no loss in acetanilide at 30 °C.