Liquid Waveguide Capillary Cell, 50 cm pathlength, 2 mm ID

Order code

Long pathlengths for small sample volumes

  • 50 cm pathlength, 1.57 mL Internal Sample Volume
  • 50–500 fold sensitivity improvement in comparison to 1cm cuvette
  • 0.55 mm ID for low sample volume sampling
  • 2 mm ID for unfiltered liquid samples
  • SMA 905 fiber optic connections
  • Wavelength Range: 230-730nm

Click here to view the current Data Sheet.  

For more information or help choosing an appropriate flow cell, see the LWCC Details page.


  • Adapts to most fiber optic detection systems
  • 20 years of manufacturing experience
  • Low UV drift


  • Trace detection of nutrients (nitrite, nitrate, phosphate, iron) in seawater
  • Environmental and oceanographic monitoring
  • Drinking water analysis
  • Colored dissolved organic matter (CDOM)
  • Process control

UV/VIS/NIR absorbance spectroscopy is governed by Beer’s Law, where the absorbance signal is proportional to chemical concentration, light path length and the compound’s specific molar absorption coefficient. Typical optical pathlengths of cuvettes and flow cells are between 0.2cm and 10 cm. Longer pathlengths are difficult to achieve due to mechanical constraints. Liquid Waveguide Capillary Cells (LWCCs) fill this gap. LWCCs are fiber optic flow cells that combine an increased optical pathlength (10–500 cm) with small sample volumes ranging from 2.4 µL to about 3mL. Compared with a standard 1cm cell, a 1 mAU signal is enhanced one hundred fold with a 100 cm flowcell to 100 mAU, using WPI’s patented aqueous waveguide technology.* They can be connected via optical fibers to a spectrophotometer with fiber optic capabilities. Ultra-sensitive absorbance measurements can be performed in the ultraviolet (UV), visible (VIS) and near-infrared (NIR) to detect low sample concentrations in a laboratory or process control environment.

Your sample is the core of a light guide

WPI’s Liquid Waveguide Capillary Cells are made of fused silica tubing with an outer coating of a low refractive index polymer. Your liquid sample is guided through the capillary and represents the core of the waveguide. The hydrophilic character of the fused silica capillary inner wall results in high signal stability and easy removal of air bubbles trapped in the flow cell. However, the transmission of the LWCC is mainly dependent on the intrinsic attenuation of the sample liquid. In case of water, a usable wavelength range from 250 nm to 720 nm wavelength can be observed in a 100 cm pathlength LWCC. Using a 500 cm pathlength LWCC will reduce that transmission range from 300 nm to about 700 nm. However, when switching from water to methanol as a solvent, transmission into the NIR are possible with suitable light sources and detectors.


The LWCC-3xxx series of flow cells uses traditional HPLC type 10-32 coned port fittings with 1/32 inch tubing for liquid connection and 500 µm SMA fiber optic adapters for light input and output. The LWCC-4xxx series of flow cells uses 1/4-28 flangless flat bottom fittings with 0.125" tubing 500 µm SMA fiber optic adapters. Liquid can be pumped into the flow cells using (in the simplest case) a sample injector (58006) and a ministar peristaltic pump (MINISTAR). The LWCC may be connected directly to a fluid injection analysis (FIA) system or to a gas segmented fluid injection analysis (GFIA) system via a debubbler. Finally, for routing discrete measurements, WPI’s LWCC Injection system (89372) may be used when the sample is injected into a constant flow via an injection loop of 3–4 times the internal flow cell volume to ensure a stable baseline and avoid the introduction of micro air bubbles into the flow cell.


WPI’s LEDSpec detection system can be used for monochromatic light detection. For example, you may use it for nitrite analysis at 540 nm with up to four (4) LWCCs per instrument. When the entire spectral shape of an absorbance curve is required for analysis, WPI’s TIDAS E Base spectrometer with a D4H or a FO-6000, or the TIDAS S300 spectrophotometer can be used. LWCCs have been used in a variety of applications, such as liquid chromatography, stopped-flow and colormetric detection, drinking water analysis, as well as environmental and oceanographic monitoring systems. Accessory: LWCC Injection System For flow analysis, including simple fluid injection analysis (FIA) setups, add WPI’s LWCC injection system (89372). A selection valve provides baseline or cleaning solutions to the sample stream. The injection valve injects a sample into the stream, avoiding the introduction of air bubbles or changes of flow rate.

Related Patents

Micro Chemical Analysis Employing Flow Through Detectors, 1995, U.S. Patent No. 5,444,807.

Aqueous Fluid Core Waveguide, 1996, U.S. Patent No. 5,507,447.

Long Capillary Waveguide Raman Cell, 1997, U.S. Patent No. 5,604,587.

Chemical Sensing Techniques Employing Liquid-Core Optical Fibers, U.S. Patent No. 6,016,372


These spectra show the optimal detection limits for LWCCs of varying pathlength. 

  LWCC-3050 LWCC-3100 LWCC-3250 LWCC-3500  LWCC-4010 LWCC-4050 LWCC-4100
Optical Pathlength  50 cm  100 cm  250 cm  500 cm 10 cm 50 cm 100 cm
Internal Volume  125 µL  250 µL  625 µL  1250 µL 0.31 mL 1.57 mL 3.1 mL
Fiber Connection  500 µm SMA 600µm SMA
Transmission @254nm*  20  10  5  - 4 3 2
Transmission @540nm*  35  30  25  20 5 4 3
Noise [mAU]**  <0.1  <0.2  <0.1  <1.0 <0.1 <0.2 <0.5
Maximum Pressure  100 PSI
Wetted Material  PEEK, Fused Silica, PTFE
Liquid Input  Standard 10-32 Coned Port Fitting

* Referenced using coupled 500µm fibers        
** Measured using ASTM E685-93            
*** A one-meter waveguide of 550µm internal diameter requires approximately 1.5PSI for water flow of 1.0mL/min.


When comparing light throughput versus wavelength of three fiber optic cables, the greater the diameter of the cable, the better the LWCC performance up to 500µm which is the input diameter of the SMA connector.

   Standard 10-32 Coned Port Fitting


Ye, C., Zhou, X., Pu, D., Stutz, J., Festa, J., Spolaor, M., … Knote, C. (2016). Rapid cycling of reactive nitrogen in the marine boundary layer. Nature, 532(7600), 489–491.

Liu, Y., & Lu, K. (2015). In situ Monitoring of Atmospheric Nitrous Acid based on Multi-pumping flow system and Liquid Waveguide Capillary Cell: development and field applications. EGU General Assembly 2015, Held 12-17 April, 2015 in Vienna, Austria.  id.8298, 17.

Wise, M. E., Imholt, F., & Caylor, R. (2014). Composition and Optical Properties of Secondary Organic Aerosol Particles. Retrieved from

Catelani, T. A., Tóth, I. V., Lima, J. L. F. C., Pezza, L., & Pezza, H. R. (2014). A simple and rapid screening method for sulfonamides in honey using a flow injection system coupled to a liquid waveguide capillary cell. Talanta, 121, 281–7.

Zimmer, L. A., & Cutter, G. A. (2012). High resolution determination of nanomolar concentrations of dissolved reactive phosphate in ocean surface waters using long path liquid waveguide capillary cells (LWCC) and spectrometric detection. Limnology and Oceanography: Methods, 10(8), 568–580.

Müller, M., Acker, M., Taut, S., & Bernhard, G. (2010). Complex formation of trivalent americium with salicylic acid at very low concentrations. Journal of Radioanalytical and Nuclear Chemistry, 286(1), 175–180.

Heller, M. I., & Croot, P. L. (2010). Kinetics of superoxide reactions with dissolved organic matter in tropical Atlantic surface waters near Cape Verde (TENATSO). Journal of Geophysical Research, 115(C12), C12038.

Hecobian, A., Zhang, X., Zheng, M., Frank, N., Edgerton, E. S., & Weber, R. J. (2010). Water-Soluble Organic Aerosol material and the light-absorption characteristics of aqueous extracts measured over the Southeastern United States. Atmos. Chem. Phys. Atmospheric Chemistry and Physics, 10, 5965–5977.

Gimbert, L. J., Haygarth, P. M., & Worsfold, P. J. (2007). Determination of nanomolar concentrations of phosphate in natural waters using flow injection with a long path length liquid waveguide capillary cell and solid-state spectrophotometric detection. Talanta, 71(4), 1624–1628.

Belz, M. (2007). Simple and sensitive protein detection system using UV LEDs and liquid core waveguides. In T. Vo-Dinh, R. A. Lieberman, & G. Gauglitz (Eds.), Proceedings of SPIE (Vol. 6755, p. 675505). SPIE.

Schofield, O., Kerfoot, J., Mahoney, K., Moline, M., Oliver, M., Lohrenz, S., & Kirkpatrick, G. (2006). Vertical migration of the toxic dinoflagellate Karenia brevis and the impact on ocean optical properties. Journal of Geophysical Research, 111(C6), C06009.

Schofield, O., Bergmann, T., Oliver, M. J., Irwin, A., Kirkpatrick, G., Bissett, W. P., … Orrico, C. (2004). Inversion of spectral absorption in the optically complex coastal waters of the Mid-Atlantic Bight. Journal of Geophysical Research, 109(C12), C12S04.

United States. National Aeronautics and Space Administration. Office of Aero-Space Technology. (2002). Spinoff 2002. U.S. G.P.O.

Zhelyaskov, V. R., Liu, S., & Broderick, M. P. (2000). Analysis of nanoliter samples of electrolytes using a flow-through microfluorometer. Kidney International, 57(4), 1764–1769.

Zimmer, L. A., & Cutter, G. A. (2012). High resolution determination of nanomolar concentrations of dissolved reactive phosphate in ocean surface waters using long path liquid waveguide capillary cells (LWCC) and spectrometric detection. Limnology and Oceanography: Methods, 10(8), 568–580.

Ye, C., Zhou, X., Pu, D., Stutz, J., Festa, J., Spolaor, M., … Knote, C. (2016). Rapid cycling of reactive nitrogen in the marine boundary layer. Nature, 532(7600), 489–91. 

N. Rastogi, M. Oakes, J.Schauer, M. shafer, B. Majestic, R. Weber, "New Technique for Online Measurement of Water-Solulble Fe(II) in Atmospheric Aerosols ", Environmental Science and Technology, Feb 27, 2009, 43 (7), 2425-2430

M.Belz, “Simple and Sensitive Protein Detection System using UV LEDs and Liquid Core Waveguides”, Advanced Environmental, Chemical, and Biological Sensing Technologies V, Optics East, Oct 2007, Proc SPIE, Vol. 6755, 675505.

J.Z. Zhang, “Enhanced Sensitivity in Flow Injection using a Long Pathlength Liquid Waveguide Capillary Flowcell for Spectrophotometric Detection”, Analytical Sciences, Jan 2006, Vol. 22, 57.

J.Z. Zhang, “Shipboard Automated Determination of Trace Concentrations of Nitrite and Nitrate in Oligotrophic Water by Gas-Segmented Continuous Flow Analysis with a Liquid Waveguide Capillary Flow Cell”, Deep Sea Research I, 2000, Vol. 47, 1157.

M. Belz, P. Dress, A. Sukhitskiy, S. Liu, “Linearity and Effective Optical Pathlength of Liquid Waveguide Capillary Cells”, Part of the SPIE Conference on Internal Standardization and Calibration; Architectures for Chemical Sensors, Boston Mass., Sept 1999, SPIE Vol. 3856, 271.

Catelani TA, Tóth IV, Lima JL, Pezza L, Pezza HR, "A simple and rapid screening method for sulfonamides in honey using a flow injection system coupled to a liquid waveguide capillary cell," Talanta. 2014 Apr;121:281-7. doi: 10.1016/j.talanta.2013.12.034. Epub 2014 Jan 3.

Ma J, Yuan D, Byrne RH, "Flow injection analysis of trace chromium (VI) in drinking water with a liquid waveguide capillary cell and spectrophotometric detection," Environ Monit Assess. 2014 Jan;186(1):367-73. doi: 10.1007/s10661-013-3381-2. Epub 2013 Aug 13.

Feng S, Zhang M, Huang Y, Yuan D, Zhu Y, "Simultaneous determination of nanomolar nitrite and nitrate in seawater using reverse flow injection analysis coupled with a long path length liquid waveguide capillary cell," Talanta. 2013 Dec 15;117:456-62. doi: 10.1016/j.talanta.2013.09.042. Epub 2013 Sep 25.

Worsfold PJ, Clough R, Lohan MC, Monbet P, Ellis PS, Quétel CR, Floor GH, McKelvie ID, "Flow injection analysis as a tool for enhancing oceanographic nutrient measurements--a review," Anal Chim Acta. 2013 Nov 25;803:15-40. doi: 10.1016/j.aca.2013.06.015. Epub 2013 Jun 20.

Sánchez-Quiles D, Tovar-Sánchez A, Horstkotte B, "Titanium determination by multisyringe flow injection analysis system and a liquid waveguide capillary cell in solid and liquid environmental samples," Mar Pollut Bull. 2013 Nov 15;76(1-2):89-94. doi: 10.1016/j.marpolbul.2013.09.024. Epub 2013 Oct 3.

Kjær HA, Vallelonga P, Svensson A, Kristensen ME, Tibuleac C, Bigler M., "Continuous flow analysis method for determination of dissolved reactive phosphorus in ice cores," Environ Sci Technol. 2013 Nov 5;47(21):12325-32. doi: 10.1021/es402274z. Epub 2013 Oct 15.

Zhu Y, Yuan D, Huang Y, Ma J, Feng S. , "A sensitive flow-batch system for on board determination of ultra-trace ammonium in seawater: Method development and shipboard application," Anal Chim Acta. 2013 Sep 10;794:47-54. doi: 10.1016/j.aca.2013.08.009. Epub 2013 Aug 9.

Lin JF, Sun ZH, Cao WX, Hu SB, Xu ZT, "Construction and application of an onboard absorption analyzer device for CDOM," Guang Pu Xue Yu Guang Pu Fen Xi. 2013 Apr;33(4):1141-5. Chinese.

Tóth IV, Santos IC, Azevedo CF, Fernandes JF, Páscoa RN, Mesquita RB, Rangel AO, "Flow-injection spectrophotometric determination of bromate in bottled drinking water samples using chlorpromazine reagent and a liquid waveguide capillary cell," Anal Sci. 2013;29(5):563-70.

Statham PJ, Jacobson Y, van den Berg CM., "The measurement of organically complexed FeII in natural waters using competitive ligand reverse titration," Anal Chim Acta. 2012 Sep 19;743:111-6. doi: 10.1016/j.aca.2012.07.014. Epub 2012 Jul 20.

Horstkotte B, Alexovič M, Maya F, Duarte CM, Andruch V, Cerdá V., "Automatic determination of copper by in-syringe dispersive liquid-liquid microextraction of its bathocuproine-complex using long path-length spectrophotometric detection," Talanta. 2012 Sep 15;99:349-56. doi: 10.1016/j.talanta.2012.05.063. Epub 2012 Jun 5.

Páscoa RN, Tóth IV, Rangel AO., "Review on recent applications of the liquid waveguide capillary cell in flow based analysis techniques to enhance the sensitivity of spectroscopic detection methods," Anal Chim Acta. 2012 Aug 20;739:1-13. doi: 10.1016/j.aca.2012.05.058. Epub 2012 Jun 12. Review.

Sun ZH, Zhou W, Xu ZT, Ye HB, Yang CY, Lin JF, Hu SB, Yang YZ, Li C, Cao WX., "Progress in Teflon AF LWCC/LCW applications," Guang Pu Xue Yu Guang Pu Fen Xi. 2011 Nov;31(11):2881-5. Chinese.

Avivar J, Ferrer L, Casas M, Cerdà V., "Smart thorium and uranium determination exploiting renewable solid-phase extraction applied to environmental samples in a wide concentration range," Anal Bioanal Chem. 2011 Jul;400(10):3585-94. doi: 10.1007/s00216-011-5005-4. Epub 2011 May 14.

Avivar J, Ferrer L, Casas M, Cerdà V., "Lab on valve-multisyringe flow injection system (LOV-MSFIA) for fully automated uranium determination in environmental samples," Talanta. 2011 Jun 15;84(5):1221-7. doi: 10.1016/j.talanta.2010.12.018. Epub 2010 Dec 15.

Páscoa RN, Tóth IV, Rangel AO., "Spectrophotometric determination of zinc and copper in a multi-syringe flow injection analysis system using a liquid waveguide capillary cell: application to natural waters," Talanta. 2011 Jun 15;84(5):1267-72. doi: 10.1016/j.talanta.2011.01.023. Epub 2011 Jan 19.

Silva AS, Tóth IV, Pezza L, Pezza HR, Lima JL., "Determination of glyphosate in water samples by multi-pumping flow system coupled to a liquid waveguide capillary cell," Anal Sci. 2011;27(10):1031-6.

Patey MD, Achterberg EP, Rijkenberg MJ, Statham PJ, Mowlem M., "Interferences in the analysis of nanomolar concentrations of nitrate and phosphate in oceanic waters," Anal Chim Acta. 2010 Jul 19;673(2):109-16. doi: 10.1016/j.aca.2010.05.029. Epub 2010 May 26.

Avivar J, Ferrer L, Casas M, Cerdà V., "Automated determination of uranium(VI) at ultra trace levels exploiting flow techniques and spectrophotometric detection using a liquid waveguide capillary cell," Anal Bioanal Chem. 2010 May;397(2):871-8. doi: 10.1007/s00216-010-3600-4. Epub 2010 Mar 17.

Amornthammarong N, Zhang JZ., "Liquid-waveguide spectrophotometric measurement of low silicate in natural waters," Talanta. 2009 Aug 15;79(3):621-6. doi: 10.1016/j.talanta.2009.04.050. Epub 2009 May 3.

Ma J, Yuan D, Zhang M, Liang Y., "Reverse flow injection analysis of nanomolar soluble reactive phosphorus in seawater with a long path length liquid waveguide capillary cell and spectrophotometric detection," Talanta. 2009 Apr 15;78(1):315-20. doi: 10.1016/j.talanta.2008.11.017. Epub 2008 Nov 25.

Rastogi N, Oakes MM, Schauer JJ, Shafer MM, Majestic BJ, Weber RJ., "New technique for online measurement of water-soluble Fe(II) in atmospheric aerosols," Environ Sci Technol. 2009 Apr 1;43(7):2425-30.

Li QP, Hansell DA., "Intercomparison and coupling of magnesium-induced co-precipitation and long-path liquid-waveguide capillary cell techniques for trace analysis of phosphate in seawater," Anal Chim Acta. 2008 Mar 17;611(1):68-72. doi: 10.1016/j.aca.2008.01.074. Epub 2008 Feb 7.

Levitskaia TG, O'Hara MJ, Sinkov SI, Egorov OB., "Direct spectrophotometric analysis of Cr(VI) using a liquid waveguide capillary cell," Appl Spectrosc. 2008 Jan;62(1):107-15. doi: 10.1366/000370208783412690.

Wang ZA, Liu X, Byrne RH, Wanninkhof R, Bernstein RE, Kaltenbacher EA, Patten J., "Simultaneous spectrophotometric flow-through measurements of pH, carbon dioxide fugacity, and total inorganic carbon in seawater," Anal Chim Acta. 2007 Jul 16;596(1):23-36. Epub 2007 May 31.

Gimbert LJ, Haygarth PM, Worsfold PJ., "Determination of nanomolar concentrations of phosphate in natural waters using flow injection with a long path length liquid waveguide capillary cell and solid-state spectrophotometric detection," Talanta. 2007 Mar 15;71(4):1624-8. doi: 10.1016/j.talanta.2006.07.044. Epub 2006 Aug 30.

Zhang JZ., "Enhanced sensitivity in flow injection analysis using a long pathlength liquid waveguide capillary flow cell for spectrophotometric detection," Anal Sci. 2006 Jan;22(1):57-60.

Santana-Casiano JM, González-Dávila M, Millero FJ., "Oxidation of nanomolar levels of Fe(II) with oxygen in natural waters," Environ Sci Technol. 2005 Apr 1;39(7):2073-9.

Kirkpatrick GJ, Orrico C, Moline MA, Oliver M, Schofield OM., "Continuous hyperspectral absorption measurements of colored dissolved organic material in aquatic systems," Appl Opt. 2003 Nov 20;42(33):6564-8.

Deng G, Wei L, Collins GE., "Sensitive detection of beryllium using a fiber optic liquid waveguide cell," Talanta. 2003 May 28;60(1):9-16. doi: 10.1016/S0039-9140(03)00060-2.

Zhang JZ, Chi J., "Automated analysis of nanomolar concentrations of phosphate in natural waters with liquid waveguide," Environ Sci Technol. 2002 Mar 1;36(5):1048-53.

Dasgupta PK, Genfa Z, Li J, Boring CB, Jambunathan S, Al-Horr R., "Luminescence detection with a liquid core waveguide," Anal Chem. 1999 Apr 1;71(7):1400-7. doi: 10.1021/ac981260q.


Typical LWCC setup includes an injection system, a pump, and a spectrophotometer.

Copyright © World Precision Instruments. All rights reserved.