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Please see our Total Organic Carbon Analyzer (TOC Analyzers) section to find manufacturers that sell these products
A total organic carbon (TOC) analyzer measures the amount of TOC present in a liquid or water sample. In environmental applications, TOC is an important indicator of the amount of natural organic matter in the drinking water source, which correlates to the formation of carcinogens. In pharmaceutical and biotechnology applications, TOC is an indicator of the levels of endotoxins and microbes. TOC is also an indicator in monitoring manufacturing processes and cleaning procedures.
There are several TOC analyzers on the market for pharmaceutical and environmental applications.
TOC analysis methods
TOC analyzers can measure total carbon (TC), total organic carbon (TOC), inorganic carbon (IC), purgeable organic carbon (POC), and nonpurgeable organic carbon (NPOC).
TOC analyzers only actually measure total carbon. TOC analysis always requires accounting for IC. In the TOC technique, IC is removed first, and TOC is measured. In the TC-IC technique, TOC is measured as a difference between TC and IC. In the TOC-NPOC technique, TOC is measured as the sum of NPOC and POC.
Whatever technique is used, TOC analysis follows three stages: acidification, oxidation, and detection.
Acidification
The sample is acidified for the removal of the IC and POC gases. These gases can be released to the detector for TOC measurement by the TC-IC technique or to the air for TOC measurement by the TOC-NPOC technique.
Oxidation
TOC analyzers oxidize carbon to CO2 by several methods.
In the high-temperature combustion method, a sample is oxidized in a high-temperature furnace. The CM150 analyzer from UIC, Inc. relies on high-temperature combustion.
In the high-temperature combustion catalytic oxidation method, a sample is heated to 680 °C in an oxygen-rich environment and in the presence of a platinum catalyst to achieve total combustion. The TOC-L Series analyzers from Shimadzu rely on this method of oxidation.
A sample can be oxidized by the supercritical water oxidation (SCWO) method. In the SCWO method, a sample is oxidized in a supercritical state. The InnovOx analyzer from GE Analytical Instruments utilizes the SCWO method.
A sample can also be oxidized by the persulfate oxidation method. In the UV/persulfate oxidation method, UV is used to magnify the persulfate reaction. The M9 analyzer from GE Analytical Instruments relies on this method.
In the heated/persulfate oxidation method, heat is used to magnify the persulfate reaction. The TOC-VWS analyzer from Shimadzu is operated as a UV/persulfate, a heated/persulfate, or as a heated-UV-persulfate analyzer.
Detection
The use of conductivity is the most prevalent detection method of CO2. Detection is based on the differential measurement of conductivity before and after oxidization. This method is used by the M9 analyzer.
Another method of detection is nondispersive infrared (NDIR). Carbon is oxidized by the UV/persulfate oxidation method and the CO2 is swept through an NDIR. This method relies on the direct measurement of TOC instead of a differential measurement. The TOC-VWS analyzer relies on NDIR.
The use of static pressurized concentration (SPC) is a newer method. The CO2 produced in sample oxidation into the detector is concentrated and quantified in a single measurement. Teledyne Tekmar offers the Fusion analyzer and the Torch Combustion analyzer, which employ SPC.
Purchasing considerations for TOC analyzers
Choosing a TOC analyzer is a complex process. Below are some factors to consider.
Types of TOC analyzers
There are three categories of TOC analyzers: on-line, portable, and laboratory.
On-line TOC analyzers have applicability in pharmaceutical applications and for the continuous monitoring of water quality. GE Analytical Instruments provides the 500 RL analyzer for pharmaceutical applications for continuous monitoring of ultrapure and potable water.
TOC analyzers are also available as portable units for troubleshooting at any location in the water system. In the case of portable TOC analyzers, the weight of the analyzer becomes a factor. GE Analytical Instruments provides portable analyzers: the battery-operated CheckPoint sensor weighs 7.9 lb with battery and the M5310 C analyzer weighs 21.6 lb.
TOC analyzers are also available as laboratory units. An example is the M9 analyzer.
Types of samples
TOC analyzers can process a range of samples.
The CheckPoint sensor is applicable for pharmaceutical samples. The M9 Series and the 500 RL and 500 RLe analyzers are well suited for ultrapure water TOC analysis. The M5310 C Series analyzers are applicable for municipal drinking water TOC analysis.
The Shimadzu TOC-4200 analyzer is for TOC measurement in underground water and public drinking water.
The CM130 analyzer from UIC, Inc. provides TOC measurement in industrial, research, and educational laboratories.
Measurement mode
The majority of analyzers are able to measure all carbon elements as well as total nitrogen (TN) and total sulfur (TS).
The CS-2000 and CS-580 analyzers from ELTRA GmbH simultaneously measure CO2 and SO2.
The FormacsHT analyzer from Skalar Analytical B.V. measures TC, TIC, TOC, dissolved organic carbon (DOC), and NPOC; the FormacsTN analyzer measures TN; the FormacsHT/TN analyzer measures TOC and TN; and the FormacsLT analyzer measures TOC.
Measurement parameters
An important specification for TOC analyzers is the measuring range. The measuring range is in direct correlation with the oxidation method used.
As a general observation, for samples processed by the UV/persulfate oxidation method, the measuring range is lower (4 ppb to 50,000 ppb for the M5310 C analyzer and 0.3 ppb to 50,000 ppb for the M9 analyzer) than for samples processed by the high-temperature combustion method (less than 1 μg to over 10,000 μg for the CM150 analyzer).
For samples processed by the SCWO method, the measuring range is 0.5 ppm to 50,000 ppm for the InnovOx analyzer.
Regulatory compliance
Another important specification for TOC analyzers is compliance with regulations that govern their specific application.
The Standard Operating Procedure (SOP) of the CheckPoint sensor meets minimum United States Pharmacopeia (USP), European Pharmacopeia (EP), Chinese Pharmacopeia (CP), and Indian Pharmacopeia (IP) requirements.
The 500 RL and 900 Series analyzers support all other major global pharmacopeias, including USP, EP, CP, and IP.
Table 1 – Providers of TOC analyzers
Representative TOC analyzers
- Analytik Jena: multi N/C®, multi N/C 2100/2100 S, multi N/C 3100, multi N/C UV HS
- Applitek: AppliTOC®
- BioTector Analytical Systems Ltd.: BioTector analyzers
- Chemtrac: UV254 series (UV1, UVM1000, UVM51000)
- Elementar Americas: vario TOC cube, vario TOC select
- ELTRA GmbH: CS-2000, CS-580
- GE Analytical Instruments: M9 Series, 500 RL, 500 RLe, M5310 C Series, InnovOx
- Hach Company: ANATEL TOC600, 1950Plus online, ANATEL 1000 series (S-20P, XP, XP-S), GuardianBlue, ANATEL PAT700, Astro series, ANATEL A643a series
- LAR Process Analyzers AG: QuickTOCultra, QuickTOCairport, QuickTOCpurity, QuickTOCcondensate, QuickTOCpharma, QuickTOCeffluent
- Mettler-Toledo Inc.: 5000TOCi, 4000TOC, 450TOC, 502P
- Metrohm USA Inc.: ADI 7010 TOC
- OI Analytical: Aurora 1030 W, 1030C, 9210p
- Shimadzu: TOC-4200, TOC-L Series, TOC-VWS, TOC-VWP, TOC-VCSH
- Skalar Analytical B.V.: FormacsHT, FormacsTN, FormacsHT/TN, FormacsLT
- Teledyne Tekmar: Torch Combustion, Fusion
- TOC Systems: StarTOC
- UIC, Inc.: CM123, CM130, CM140, CM150, CM13, CM180, CM190, CM220, CM240, CM250
Latest development
Skalar Analytical B.V. has extended the PrimacsMCS TOC analyzer to operate in combination with the FormacsSERIES analyzers for TOC analysis on aqueous samples and solid materials.
Providers of TOC analyzers
A list of TOC analyzer providers is given in Table 1.
Lina Genovesi, Ph.D., JD, is a Technical, Healthcare, and Business Writer based in Princeton, NJ; e-mail: [email protected]; www.linagenovesi.com.
Please see our Total Organic Carbon Analyzer (TOC Analyzers) section to find manufacturers that sell these products