User Guide

For an introduction to the application and use of Certified Reference Materials in absorption spectrophotometry

Starna Scientific offers an extensive range of Certified Reference Materials for qualifying the wavelength scale of ultaviolet spectrophotometers, with an overall wavelength coverage from 190 nm to 870 nm. Rare earth oxide solutions are accepted by most Pharmacopoeias for wavelength qualification in the ultraviolet region, and Starna’s unique range of these materials gives the most extensive wavelength coverage available from any supplier.

Holmium Oxide Solution (240 - 650 nm)

Holmium-oxide-solution 

The most widely used liquid wavelength reference, recognised by  most Pharmacopoeias and standardisation bodies, including:

  • European Pharmacopoeia
  • Deutsches Arzneibuch (German Pharmacopoeia).
  • United States Pharmacopoeia
  • American Society for Testing and Materials
  • Therapeutic Goods Administration (Australia)
  • British Pharmacopoeia

When prepared in dilute perchloric acid, holmium oxide gives a spectral scan containing 14 characteristic and well - defined peaks covering the wavelength range from  240 nm to  650 nm.

Approximate peak wavelength values (in nm) are:
241, 250, 278, 288, 334, 346, 361, 385, 417, 451, 468, 485, 537, 641

More information

 

Didymium Oxide Solution (290 – 870 nm)

Didymium Oxide solution

The spectrum of didymium in perchloric acid contains 14 peaks that can be certified for wavelength, covering the range from 290 nm to 870 nm. This reference is useful for its NIR coverage, but has few peaks in the UV and is not accepted by the Pharmacopoeias for wavelength qualification in this region.

Approximate peak wavelength values (in nm) are:
298, 329, 354, 444, 469, 482, 512, 522, 576, 732, 740, 794,799, 864

More information

 
 

Combined Holmium/Didymium Solution (240 – 795 nm

 samarium

 This reference has useful peaks evenly distributed over its whole wavelength range, from 240 to 795 nm.

14 peaks are certified, with nominal values: 241, 287, 361, 416, 444, 482, 485, 522, 537, 575, 641, 732, 740 and 794 nm.

 

More information

  
 

Holmium Oxide Glass (240 - 640 nm)

 Holium glass

This solid material is physically more robust than Its liquid equivalent and can therefore be used in a more demanding  environment, so is useful as a routine wavelength calibration check. It is, however, not accepted  by all the Pharmacopoeias for  wavelength qualification

Approximate peak wavelength values (in nm) are:
242, 279, 288, 334,  361, 419, 446, 454, 460, 537, 638

More information

  
 

Combined Holmium/Neutral Density Glass

 holmium and didymium

With this combined filter, the holmium spectrum is superimposed on an approximately constant 1A background, useful as an absorbance accuracy check. 7 peak wavelengths are certified at nominal values of 361, 419, 446, 454, 460, 537 and 638 nm.

Absorbance values, nominally 1A, are certified at wavelengths between the holmium peaks at 431, 516, 557, 594 and 623 nm

 

More information

  

Didymium Glass Filter (430 – 890 nm)

RM-DG

The didymium (neodymium & praseodymium) Glass  filter  produces characteristic peaks in the  visible region of the spectrum, with 11 well-defined peaks  from  430 nm to 890 nm.

Approximate peak wavelength values (in nm) are: 
431, 473, 513, 529, 573, 585, 685, 741, 749, 807, 879.

More information

  

Combined Didymium/Neutral Density Glass

didymium and ndf

With this combined filter, the holmium spectrum is superimposed on an approximately constant 1A background, useful as an absorbance accuracy check. 9 peak wavelengths are certified at nominal values of 473, 514, 530, 572, 586, 739, 748, 807 and 879 nm.

Absorbance values, nominally 1A, are certified at wavelengths between the didymium peaks, at 410, 455, 550, 637 and 773 nm.

More information

  

Rare Earth Oxide Solution
(200 -270 nm)

Samarium-Oxide-

With five certified peaks in this region, this rare earth solution is a convenient way of qualifying spectrophotometers in the far UV.

Approximate peak wavelength values (in nm) are: 201, 211, 223, 240, 254 

More information

  
 

Deep UV Reference (190 - 230 nm)

 DUV

This novel reference material is certified for wavelength qualification at nominal values of 191 nm, 209 nm and 226 nm. It is also certified for absorbance qualification at these wavelengths. Approximate absorbance values are 0.9 A, 0.3 A and 0.9 A respectively.

More information

  
 

Starna Green Broadband References
(250 - 650 nm)

 Starna-Green-Broadband-References-

Specially developed for instruments with wider Spectral Band Widths (up to 20 nm), but a good general purpose reference, Starna Green has broad peaks at  258 nm, 416 nm and 630 nm. This reference material may also be used to qualify the absorbance scale, and four different concentrations cover an absorbance range from approximately 0.25 A to 1.A. The references are available singly or in any combination.

More information

  
 

Samarium Oxide Solution
(230 – 560 nm)

 samarium

Samarium perchlorate is a particularly useful reference material for checking the wavelength scale over the commonly  used region from 200 nm to 500 nm. 
Approximate peak wavelength values (in nm) are:
235, 279, 290, 305, 318, 332, 344, 362, 374, 391, 401, 415, 464, 479

More information

  

 

Starna wide-range wavelength references 
(335 – 1945 nm)

This exceptionally wide-range filter contains a mixture of rare earth oxides and provides 20 peaks for wavelength calibration between in the NIR. It is equivalent to NIST SRM 2065. Nominal peak wavelength values (in nm) are: 335, 345, 361, 375, 386, 402, 418, 485, 538, 583, 642, 748, 804, 976, 1076, 1151, 1222, 1366, 1469, 1945

 

More information