CIL Research Products

Amino Acids




Bile Acids

CIL Bile Acid Analytical Standards are Predominantly available in D-labeled and unlabeled forms and span primary, secondary, and conjugated classes. These bile acids are highly characterized, >97% isotopic enrichment and chemical purity and are available as a powder or in a solution.


Biological Standards

Information obtained in clinical diagnostics requires a level of confidence that is much higher than most other fields due to the implications of the results. They can be indicative of a disease state, a chronic illness, the effects of a drug or a substance in the body. For this reason, the staffing, instrumentation, reagents and supplies in these labs are of the highest quality. CIL offers a wide variety of high-quality isotope-labeled reagents that are routinely used as reference standards in both research and diagnostic settings. These products are manufactured to meet high quality control specifications for both isotopic enrichment and chemical purity, which are invaluable to accurate and precise results as required by clinical labs. As researchers in the clinical field search for faster, more accurate tests, they are often driven toward mass spectrometry. The use of stable isotopes combined with this technology is emerging as one of the most powerful ways to increase throughput and accuracy in clinical testing.


Buffers and Reagents

CIL offers a wide selection of deuterated buffers and reagents for use with aqueous solution.






CellFree Protein Expression

Producing proteins at will, often a bottleneck in post-genome studies, has become a reality with the advent of the robust wheat germ cell-free protein expression system. CellFree Sciences’ ENDEXT® wheat germ cell-free system permits both high throughput protein screening and microgram- to milligram-scale protein production overnight. Protein synthesis protocols for the ENDEXT® system have been optimized for a wide range of proteins. They have also been incorporated into robotic protein synthesizers, versatile Protemist® DT II and mass-producing Protemist® XE. Being eukaryotic and free from physiological constraints that hamper in vivo systems, the wheat germ cell-free system allows synthesis, with or without additives, of a broad spectrum of protein and protein complexes ranging from 10 kDa to 360 kDa in well-folded and soluble forms.


Cell Growth Media




Cellular Metabolism & Metabolomics

Isotope tracers are essential tools for monitoring metabolic pathway activity, i.e. flux. To quantitate flux in central carbon metabolism in cultured mammalian cells, D-Glucose (13C6, 99%) (CLM-1396) or L-Glutamine (13C5, 99%) (CLM-1822) is added to media lacking these principal nutrients. Cells are grown in the labeled media, and metabolite labeling is measured by GC/MS or LC/MS. Glucose has traditionally been considered to be the primary carbon source for many cell types, especially cancer cells. Recent studies show, however, the glutamine often plays a predominant role in feeding the tricarboxylic acid (TCA) cycle. The extent of contribution of glutamine to TCA cycle four-carbon units can be measured based on malate and asparate labeling, and to two-carbon units based on acetylCoA and fatty acid labeling. Citrate is a particularly informative molecule, because it reflects both two- and four-carbon units of the TCA cycle. With modern instrumentation, it is possible to measure in parallel the isotope labeling of all of these species, and dozens more, enabling systems-level flux quantitation. These methods can translate also to the in vivo setting, with mice or patients infused with labeled nutrients prior to resection of a tumor or other tissue specimen. The importance of metabolism in both bioengineering and disease pathophysiology is leading to wide application of these methods across the biochemical sciences.


Chemical Tagging Reagents

Metabolic incorporation of heavy isotopes into a proteome, as in SILAC and SILAM, is a popular method to prepare an internal standard or labeled control; however, some organisms and animals are not amenable to metabolic incorporation. Fortunately, analytes may be readily modified through chemical tagging reactions.  Examples include the reductive animation of primary amines in proteins or peptides and hydrazide tagging of free N-linked glycans in proteomic samples. Since tagging reagents are compatible with many biological sample types, CIL is delighted to offer a collection of reductive methylation reagents and a glycan-tagging kit termed INLIGHT® (Individuality Normalization when Labeling with Isotopic Glycan Hydrazide Tag) for 2- or 3-plex relative quantitation.



Elements and Compounds

CIL offers an extensive inventory of stable isotope-labeled elements and compounds. The isotopic enrichment and chemical purity is lot-/product-specific and is provided with the supplied material. The products are amenable to a wide ranging array of applications, encompassing conductivity, agriculture, botany, biosample (e.g. urine and bone), and quantitative proteomic analyses via element-specific detection (e.g., ICP-MS).


Fatty Acids & Lipids

Lipid metabolism refers to the metabolic processes involved in the synthesis and degradation of lipids in an organism. Fatty acid metabolism consists of the catabolic and anabolic processes that generate energy, primary metabolites and other key biological molecules from fatty acids. Combined with powerful mass spectrometry techniques, stable isotope tracers can be used to quantify the appearance and decomposition rates of lipids, fatty Related Products Catalog No. Description DLM-9180 Docosanoic acid (22,22,22-D3, 98%) CLM-1397 Glycerol (2-13C, 99%) CLM-1857 Glycerol (1,3-13C2, 99%) CLM-1510 Glycerol (13C3, 99%) DLM-1229 Glycerol (1,1,2,3,3-D5, 99%) DLM-558 Glycerol (D8, 99%) CDLM-7745 Glycerol (13C3, 99%; D8, 98%) CP 95% DLM-8510 Hexacosanoic acid (12,12,13,13-D4, 98%) CLM-3960 Linoleic acid, ethyl ester (linoleate-U-13C18, 98%) CP 95%+ DLM-208 Myristic acid (D27, 98%) CLM-293 Octanoic acid (1-13C, 99%) CLM-3981 Octanoic acid (13C8, 99%) CLM-3707 2-Octanoyl-1,3-distearin (octanoic-1-13C, 99%) CLM-2492 Oleic acid (methyl-13C, 99%) CLM-460 Oleic acid (U-13C18, 98%) CP 95% DLM-1891 Oleic acid (D33, 98%) CLM-8856 Oleic acid, potassium salt (U-13C18, 98%) CP 95% CLM-8763 Oleic acid, sodium salt (U-13C18, 98%) acids and glycerol in the body. Specifically, stable isotope tracers are often used to study fatty acid oxidation, glycerol kinetics and de novo lipogenesis, and lipolysis. Below is a list of stable isotopelabeled substrates that can be utilized to study fatty acid and lipid metabolism.


Deuterated Reagents for Electronics

CIL offers a series of deuterated organic molecules and deuterium gas commonly used in the manufacturing of microelectronics and OLEDs, which contribute to the increased lifetime of the devices.


Deuterated Reagents for Pharmaceuticals

In recent years, some pharmaceutical companies have begun to investigate deuteration of molecules that may provide advantages over their existing nondeuterated counterparts. In addition, increasing research into the potential medical advantages of new deuterated drugs is also occurring.


Drug Standards

CIL offers a wide selection of isotopically labeled drug standards that are ican be used for drug screeing.



Cambridge Isotope Laboratories, Inc. can provide a variety of gases, labeled with 13C, D, 15N, and/or 18O, to meet all of your research needs. We can also offer gas mixtures, and we are able to offer a range of packaging options for most gases.


cGMP Products

With increasing requirements from institutional review boards (IRBs) and governmental agencies, partnering with CIL for your next stable isotope cGMP (current good manufacturing practices) project can help ensure your regulatory compliance. With the world’s largest 13C and 18O isotope-separation plants, CIL is able to provide the raw materials necessary for your project. Your compound of interest most likely already appears in CIL’s extensive list of research compounds – if not, CIL’s team of PhD chemists can determine the best method of synthesis for incorporating 13C, 15N, D, 17O, and/or 18O into your compound.



The glycan standards available are in 13C6 -labeled and unlabeled forms. These encompass a broad range of categories (e.g., N-linked, O-linked, and fucosylated) and have been highly characterized using a number of analytical techniques (e.g. 1H NMR and ESI-MS). The standards are supplied as purified powders in 500 pmol quantities (alternate quantities available upon request) and can be used for a variety of applications (e.g. health and disease assessment).


IROA Biochemical Quantitation

These kits contain the protein reagents and tools necessary for the successful metabolic labeling, identification, and quantitation of metabolites in various cell populations. Refer to product list for details. Kit Features and Benefits Eliminates technical and analytical variance , Increases reliability, Removes artifacts and noise increases precision and determination of metabolome, Reproducible identification of knowns/unknowns, Accurate, relative quantitation, Easy statistical interpretation of sample results, Broad applicability with experimental perturbations being user-defined.


a-Keto Acids

CIL is proud to offer a large selection of α-ketobutyric and α-ketoisovaleric acids, along with 3-13C pyruvate, for use in selective methyl and side-chain labeling. Uniform 13C-labeled forms of the precursors are used in conjunction with 13C6 glucose to produce uniform 13C-labeled Ile and Leu.


Metabolomics Kits

Quality control (QC) of methods and processes is an essential factor toward the generation of reliable mass spectrometry (MS) data. In order to obtain accurate and precise metabolomic data that can be reproduced by independent laboratories around the world using different MS technologies, standardized protocols and reagents are necessary.


Methyl Labeling Kits and Amino Acids

CIL offers kits of conveniently packaged reagents for labeling proteins with isoleucine, leucine, valine, and alanine (i.e. “ILVA” labeling) or only alanine. These kits are for use with 1 L amounts of deuterated minimal media. Please see CIL Application Note 25 for more details regarding ILVA and alanine labeling. CIL also is offering methionine (2,3,3,4,4-D5 , methyl-13CH3 ) for use with deuterated minimal media to provide a new methyl probe in addition to Leu, Ile, Val, and Ala.


Microbiological and Pyrogen Tested

CIL offers microbiological and pyrogen testing for many of our research-grade products. For these products, denoted as -MPT, the bulk material is tested at release for S. aureus, P. aeruginosa, E. coli, Salmonella sp, aerobic bacteria, yeast, mold and bacterial endotoxins. Subsequent aliquots are not retested. Microbiological testing does not imply suitability for any intended use. For most -MPT products, CIL also offers an Enhanced Technical Data Package (EDP). It includes all data that normally accompanies the -MPT product, plus additional information pertaining to the synthesis, purity and stability of the product. This is available for an additional charge.


Mouse Express® Mouse Feed

SILAM has been accomplished using both stable isotope-labeled amino acids as well as 15N Spirulina. CIL offers custom feed for the metabolic incorporation of stable isotopes into mice and rats.


Mouse Express® Mouse Tissue

Mass spectrometry methods employing isotope-enriched internal standards have been used quite successfully to quantitatively characterize and compare the proteome from many different cell and tissue types. Quantification of a protein is best achieved by comparing a surrogate peptide with an identical peptide that is labeled with heavy isotopes. A typical quantitative MS-based proteomic workflow will include spiking a known amount of an isotope-enriched peptide to one or more samples to serve as a quantitative internal standard. Unfortunately, in order to simultaneously characterize a large number of proteins within the same sample or across samples, the use of multiple enriched peptides is required which can become prohibitively cumbersome and expensive. To solve this problem, CIL offers MouseExpress® Mouse Tissue, a whole mouse tissue highly enriched with Lysine13C6 or 15N. The tissue already contains thousands of different heavy-labeled proteins that will yield labeled peptides for use in quantification. MouseExpress® Mouse Tissue allows for an elegant, simultaneous direct comparison of hundreds or even thousands of proteins across samples. MouseExpress® Mouse Tissue may be further processed by the user to enrich certain fractions to simplify the analysis and enhance detectability. MouseExpress® Mouse Tissue may also be used to characterize non-murine, mammalian samples, due to sufficient genetic homology between mice and other mammals. CIL is pleased to offer intact stable isotope-enriched mouse tissue to assist the MS proteomic community. The use of enriched mouse tissue as an internal standard allows for proteomic investigation at the tissue level1,2 and will accelerate the quantitative proteome comparison across biological samples.


MRI/MRS Products

Isotope labeled substrates are widely used as metabolomic tracers in both magnetic resonance imaging (MRI) and Magnetic Resonance Spectroscopy (MRS). 13C and 15N-labeled substrates are also being utilized in the rapidly emerging field of magnetic resonance imaging using hyperpolarization.


MRM PeptiQuant™ Assay Kits

To help researchers establish a robust LC-MS/MS platform for system suitability and bottom-up proteomic quantitation, Cambridge Isotope Laboratories, Inc. (CIL) is pleased to offer a number of quality control (QC) and biomarker assessment kits (BAKS) from MRM Proteomics, Inc. The QC kits are used to evaluate performance efficiency, while the BAKs are designed to assess a target panel of candidate disease protein biomarkers in human or mouse plasma samples. Each kit contains the necessary reagents and tools to perform the desired analysis.


MS/MS Standards

Tandem mass spectrometry (MS / MS) is a specific type of MS method that has two mass analyzers separated by a fragmentation chamber (collision cell) that can break ionized molecules (precursor ions, intact molecular ions) into specific and reproducible and smaller pieces or product ions. Amino acids and acylcarnitines as classes of compounds produce common highly reproducible and characterizable fragments. Using MS / MS one can selectively detect just acylcarnitines or alpha amino acids in separate scans, simultaneously, without any chromatography yet still maintain high selectivity. Therefore, MS / MS can detect many different compounds in a single analysis in about two minutes per sample. It is for this reason that MS / MS has replaced older methods for amino acid analysis and detection of metabolites such as phenylalanine for PKU and has added a series of metabolites, i.e. the acylcarnitines for a series of disorders such as MCAD (medium chain acyl CoA dehydrogenase deficiency). In total, several dozen metabolites are detected in a single analysis. Quantification is critical to MS / MS analysis and therefore requires reference standards to properly measure the concentration of the markers.


Organic Acids and Conjugate Salts

Organic acids (OAs) are important metabolites that play an essential role in an array of energy metabolism pathways (e.g., glycolysis and tricarboxylic acid cycle). In addition, short chained OAs are emerging as important regulators of host immune responses and transcriptional regulation. Their significance to cellular metabolism is heightened by their association with diseases, such as cancer and diabetes. As a result, research has been focused on quantifying OAs in various biological samples (e.g., urine, plasma, serum). In these studies, measurements of OAs were accomplished by liquid chromatography (LC) or capillary electrophoresis (CE) coupled to mass spectrometry (MS).


Protein Standards

We offer a number of isotope-labeled recombinant proteins for MS and NMR research. In MS studies, these can be added to samples at the beginning of experimental workows to help control or correct for analytical variability. This is toward improving the accuracy of protein quantification. For NMR spectroscopy, these proteins are used to assess NMR spectrometer performance, aid the development of new pulse sequences, adn for training purposes.


Protein Reagents

A diverse array of isotope-labeled prokaryotic and eukaryotic cell growth media for the production of isotope-enriched recombinant protein is available from CIL.


SILAC Kits and Reagents

SILAC refers to labeling cultured cells with heavy amino acids for quantitative proteomic analysis. Labeling an entire proteome with heavy amino acids in vivo generates an ideal standard for quantitative proteomics. When a heavy labeled proteome is mixed with an unlabeled proteome then digested, every unlabeled peptide identified by the mass spectrometer can be quantified by its corresponding heavy peptide. In SILAC, the tryptic amino acids, arginine (R) and lysine (K), contain heavy stable isotopes, so if digesting with trypsin, every peptide is labeled. This metabolic labeling strategy has been employed by hundreds of proteomic studies (see example references below). The advantage of metabolic labeling over in vitro tagging techniques is that the heavy and unlabeled samples are mixed before sample preparation, preventing variability between preparations from distorting the final quantitation results. This is especially important when extensive sample preparation (e.g. isolation of an organelle) is required.



Spirulina (U-15N, 98%+) (NLM-8401), a unique blue-green algae, in combination with a protein/amino acid-free nutrient mix, provides an efficient feed to metabolically label the entire animal proteome with 15N. A 15N rodent diet can be prepared by a custom diet vendor or in your laboratory using 15N Spirulina. Please refer to: McClatchy, D.B. and Yates, J.R., III. 2008. Stable Isotope Labeling of Mammals (SILAM). Cold Spring Harbor Laboratory. Protoc, doi:10.1101/pdb.prot4940 Spirulina cells are grown under carefully controlled conditions in specially designed photobioreactors. Various parameters, such as temperature, pH, O2 and CO2 levels are continuously monitored and controlled during the growths. Media and growth conditions have been optimized to give consistently high levels of protein while suppressing algal toxins, such as microcystine. At harvesting, the Spirulina cells are carefully processed and separated to remove residual media and any other contaminants prior to lyophilization. Each batch of cells is tested by the “Brine Shrimp Test,” an industry standard for confirmation of nontoxicity. Our Spirulina cultures are routinely checked by microscopic examination to ensure that the strains are free from other algal contaminants.


Steroids and Hormones

The use of anabolic steroids among athletes to enhance performance in sports has become an increasingly large problem over the past few decades. These athletes are routinely tested by agencies such as the World Anti-Doping Agency, to determine levels of steroids present in their bodies. Many of these tests involve taking samples of serum or urine and spiking in an internal standard or a combination of internal standards to quantitate even low levels of a given steroid or group of steroids. CIL is proud to offer highly enriched stable-isotope labeled steroids to assist with ease of quantification in these critical tests. Below are the most widely used steroids.


Synthetic Intermediates





Vitamins are essential to maintaining the health of an individual. Some are produced endogenously and some are obtained only through one’s diet. Certain levels of each vitamin are required for the function of critical organs and the metabolism of carbohydrates, fats and proteins. Vitamin deficiencies can have detrimental impacts on a number of body processes and, therefore, levels often need to be tested. Historically, immunoassays have been used to determine vitamin levels, however, the accuracy of these tests is often questioned. Recently, the powerful combination of mass spectrometry and stable isotope-labeled internal standards has proven to be one of the most accurate ways to identify and quantitate vitamins in even a low-volume sample. These tests are becoming more robust, reproducible and accurate as the sensitivity of instrumentation and the availability of internal standards both increase. CIL’s recently expanded product listing of both carbon-13 and deuterium-labeled vitamins will assist in this effort.