Evaluation of Fourier deconvolution ion mobility spectrometer as high-performance gas chromatography detector for the analysis of plant extract flavors.

The Fourier deconvolution ion mobility spectrometer (FDIMS) offers multiplexing and improves the resolving power and signal-to-noise ratio. To evaluate the FDIMS as a detector for gas chromatography for the analysis of complex samples, we connected a drift tube ion mobility spectrometer to a commercial gas chromatograph and compared the performance including resolving power, sensitivity, and linear range using 2,6-di­tert-butylpyridine. Mixed standards were also injected into the tandem system to evaluate the performance under optimized conditions. A complex plant extract sample used as natural flavoring was investigated using the resulting system. The results show that the instrument implemented with the Fourier deconvolution multiplexing method demonstrated higher performance over the traditional signal averaging method including higher resolving power, better limit of detection, and wider linear range for a variety of compounds and natural plant extract flavorings.

Endogenous n-Alkanes in Vegetable Oils: Validation of a Rapid Offline SPE-GC-FID Method, Comparison with Online LC-GC-FID and Potential for Olive Oil Quality Control.

The potential of endogenous n-alkane profiling for the assessment of extra virgin olive oils (EVOO) adulteration (blends with cheaper vegetable oils) has been studied by relatively few authors. Analytical methods used for this purpose often involve tedious and solvent-intensive sample preparation prior to analytical determination, making them unattractive. A rapid and solvent-sparing offline solid phase extraction (SPE) gas chromatography (GC) flame ionization detection (FID) method for the determination of endogenous n-alkanes in vegetable oils was, therefore, optimized and validated. The optimized method demonstrated good performance characteristics in terms of linearity (R2 > 0.999), recovery (on average 94%), and repeatability (residual standard deviation, RSD < 11.9%). The results were comparable to those obtained with online high-performance liquid chromatography (HPLC)-GC- FID ( RSD < 5.1%). As an example of an application to prove the potentiality of endogenous n-alkanes in revealing frauds, the data set obtained from 16 EVOO, 9 avocado oils (AVO), and 13 sunflower oils (SFO), purchased from the market, was subjected to statistical analysis and principal component analysis. Two powerful indices, namely (n-C29 + n-C31)/(n-C25 + n-C26) and n-C29/n-C25, were found to reveal the addition of 2% SFO in EVOO and 5% AVO in EVOO, respectively. Further studies are needed to confirm the validity of these promising indices.

Multidimensional Gas Chromatography of Organosulfur Compounds in Coffee and Structure-Odor Analysis of 2-Methyltetrahydrothiophen-3-one.

Organosulfur compounds (OSCs) in coffee remain challenging to analyze by conventional gas chromatography (GC) due to their low concentrations amid coffee's complex matrix and susceptibility to chiral-odor influences. In this study, multidimensional GC (MDGC) methods were developed to profile OSCs in coffee. Conventional GC was compared to comprehensive GC (GC×GC) for untargeted OSC analysis in eight specialty coffees, and GC×GC was found to improve the fingerprinting of OSCs in coffee (50 vs 16 OSCs identified). Of the 50 OSCs, 2-methyltetrahydrothiophen-3-one (2-MTHT) was of high interest due to its chirality and known aroma contribution. Following that, a heart-cutting method for chiral GC (GC-GC) was developed, validated, and applied to the coffees. The mean enantiomer ratio of 2-MTHT was observed to be 1.56 (R/S) in brewed coffees. Overall, MDGC techniques allowed for more comprehensive analyses of coffee OSCs, from which (R)-2-MTHT was found to be the predominant enantiomer with the lower odor threshold.

Investigation of the effect of refining on the presence of targeted mineral oil aromatic hydrocarbons in coconut oil.

The goal of this work was to investigate the impact of refining on coconut oil particularly on the most toxicologically relevant fraction of the mineral oil aromatic hydrocarbon (MOAH) contamination, namely the fraction composed by the three to seven aromatic rings. A fully integrated platform consisting of a liquid chromatography (LC), a comprehensive multidimensional gas chromatography (GC) (LC-GC × GC) and flame ionization detector (FID) was used to obtained a more detailed characterization of the MOAH sub-classes distribution. The revised EN pr 16995:2017-08 official method was used for preparing the samples, both with and without the auxiliary epoxidation step. Crude coconut oil was spiked with different MOAH standards, namely naphthalenes, alkylated naphthalenes, benzo(a)pyrene, and its alkylated homologues. Refining was modelled by deodorization at 230 °C, stripping with 10 kg/h of steam under 1 mbar vacuum for 3 h. Complete removal of the naphthalenes and reduction of more than 98.8% of the benzo(a)pyrenes was observed. Epoxidation had a significant impact on the MOAH fraction with more than three rings, but with a high dependency on the sample matrix, being significantly less evident in the refined samples than in the crude ones.

The integrated exposure assessment and potential risks of five organophosphorus pesticides in vegetables in Zhejiang, China (2018-2020).

This research surveyed the concentrations of five organophosphorus pesticides (OPs) in vegetables with the purpose of assessing the potential integrated health risks of residents. From 2018 to 2020, 870 samples of eight kinds of vegetables from Zhejiang Province were collected. Gas chromatography coupled with a flame photometric detector (GC-FPD) analyzed the five OPs. OPs were most frequently detected in celery (18.9% of samples), cowpeas (18.3% of samples), and leeks (16.9% of samples) compared to other vegetables. Among the 11 cities in Zhejiang, the cities with high detection rates of OPs were Ningbo and Hangzhou. The integrated concentrations of OPs in different cities ranged from 71.9 to 376 µg/kg. The cumulative risk assessment revealed that the estimated daily intake (EDI) of leek in Wenzhou was the highest, which was 0.0077 (mg/kg bw) and 0.0059 (mg/kg bw) in adults and children respectively. The health risks of residents who consume these vegetables were within a safe range. The data provided demonstrate the distribution and potential health hazards of OPs in commonly consumed vegetables.

Separation of C1-C15 Alkanes with a Disk-Shaped Aluminum Column Employing Mesoporous AAO as the Stationary Phase.

A new type of gas chromatographic (GC) column employing a mesoporous anodic aluminum oxide (AAO) layer as the stationary phase was developed. The gas fluidic channels were fabricated on both sides of an aluminum disk via a mechanical stamping process. The tops of the gas fluidic channels were sealed with a thick aluminum foil and a thin glass liner. The cross section of this fluidic channel is triangular in shape and consists of two aluminum surfaces and one glass surface. The diameter of the aluminum disk is 8.7 cm, and the length of the GC column is 6.0 m. The AAO layer was grown on the aluminum surface and had an average pore diameter of 50 nm and a specific surface area of 4.13 m2 g-1. The thickness of the AAO stationary phase ranged from 6-150 µm. Although thin AAO is insufficient for separating light alkanes, methane and ethane can be separated with a resolution of 4.25 using a 150 µm thick AAO stationary phase at room temperature in less than 100 s. C1 to C15 alkanes can be completely separated within 20 min when using a temperature program ramped from room temperature to 350 °C. Some limitations of this preliminary design, such as peak broadening probably arising from the triangular cross section, not yet being suitable for polar compounds, and the lack of a stationary phase on one-third of the column surface are discussed.

Development of a new and facile method for determination of chlorpyrifos residues in green tea by dispersive liquid-liquid microextraction.

In this work a simple, rapid, and environmentally friendly method has been established for the determination of chlorpyrifos residue in green tea by dispersive liquid-liquid microextraction and gas chromatography-flame photometric detection. Some experimental parameters that influence extraction efficiency, such as the kind and volume of disperser solvents and extraction solvents, extraction time, addition of salt and pH, were investigated. And the optimal experimental conditions were obtained, quantitative analysis was carried out using external standard method. The correlation coefficient of the calibration curves was 0.999 with in 0.05 mg/kg to 5 mg/kg. The results showed that under the optimum conditions, the enrichment factors of the chlorpyrifos was about 554.51, the recoveries for standard addition fell in the range from 91.94 to 104.70% and the relative standard deviations was 4.61%. The limit of quantification of chlorpyrifos in green tea was 0.02 µg/mL at the signal/noise ratio of 3.

Detection and Risk Assessments of Multi-Pesticides in Traditional Chinese Medicine Chuanxiong Rhizoma by LC/MS-MS and GC/MS-MS.

With the internationalization of traditional Chinese medicines (TCMs) and the increasing use of herbal medicines around the world, there are concerns over their safety. In recent years, there have been some sporadic reports of pesticide residues in Chuanxiong Rhizoma (CX), although the lack of systematic and comprehensive analyses of pesticide residues and evaluations of toxicological risks in human health has increased the uncertainty of the potential effects of pesticides exposure in humans. This study aimed to clarify the status of pesticide residues and to determine the health risks of pesticide residues in CX. The findings of this study revealed that 99 batches of CX samples contained pesticide residues ranging from 0.05 to 3013.17 µg/kg. Here, 6-22 kinds of pesticides were detected in each sample. Prometryn, carbendazim, dimethomorph, chlorpyrifos, chlorantraniliprole, pyraclostrobin, and paclobutrazol were the most frequently detected pesticides, with detection rates of 68.69-100%. Insecticides and fungicides accounted for 43.23% and 37.84% of the total pesticides detected, respectively. Here, 86.87% of the pesticide content levels were lower than 50 µg/kg, and a small number of samples contained carbofuran, dimethoate, and isofenphos-methyl exceeding the maximum residue levels (MRLs). A risk assessment based on the hazard quotient/hazard index (HQ/HI) approach revealed that the short-term, long-term, and cumulative risks of pesticide residues in CX are well below the levels that may pose a health risk. Worryingly, six banned pesticides (carbofuran, phorate sulfone, phorate-sulfoxide, isofenphos-methyl, terbufos-sulfone, and terbufoxon sulfoxide) were detected. This study has improved our understanding of the potential exposure risk of pesticide multi-residues in CX. The results of the study will have a positive impact on improving the quality and safety of CX and the development of MRLs for pesticide residues.

Direct Methylation for Determination of Fatty Acids in Coffee Samples by GC-FID.

The direct methylation method developed in this work for coffee samples allowed the determination of fatty acids using smaller sample amounts (100 mg), lower solvent volumes (5 mL) and shorter experimental run time (~12 min). Hence, the experiments are more economical and collaborate with green chemistry, besides favoring the health of the analyst who handles a smaller amount of solvents in a short period. Design Expert software was employed to determine the optimal concentration of the acid and base (0.7 e 1.75 molL-1) and evaluate the sonication time (5 min for both procedures). The experiments were carried out on different coffee samples in which the fat content ranging from 10.18% to 14.86%. The relative standard deviation values for intraday and interday were 2.78% and 7.8%, respectively, confirming the good precision of the proposed method for fatty acid derivatization.

The graft framework: Quantitative changes in cell wall matrix polysaccharides throughout the tomato graft union formation.

Plant cell walls provide essential functions in cell recognition, differentiation, adhesion and wound responses. Therefore, it is tempting to hypothesize that cell walls play a key role in grafting, but to date there are no quantitative studies targeting on cell wall changes during grafting. The aim of this work was to investigate the dynamics of pectic and hemicellulosic polysaccharides at the graft junctions in tomato homografts throughout the first 12 days after grafting. Cell wall fractionation, combined with ATR-FTIR spectroscopy and gas-chromatography, evidenced a marked increase in pectin content and a decrease in the degree of methyl-esterification of homogalacturonan in scion and rootstock throughout grafting. Also, recovery of tightly-bound hemicelluloses decreased at late times after grafting suggesting an increase of cross-linked hemicelluloses along grafting. In addition, immuno-dot assays revealed an increase in xyloglucan and arabinogalactan proteins in the first days after grafting, pointing to a presumed role in tissue adhesion-cohesion.

Gas chromatography of essential oil: State-of-the-art, recent advances, and perspectives.

This review is an overview of the recent advances of gas chromatography in essential oil analysis; in particular, it focuses on both the new stationary phases and the advanced analytical methods and instrumentations. A paragraph is dedicated to ionic liquids as gas chromatography stationary phases, showing that, thanks to their peculiar selectivity, they can offer a complementary contribution to conventional stationary phases for the analysis of complex essential oils and the separation of critical pairs of components. Strategies to speed-up the analysis time, thus answering to the ever increasing request for routine essential oils quality control, are also discussed. Last but not least, a paragraph is dedicated to recent developments in column miniaturization in particular that based on microelectromechanical-system technology in a perspective of developing micro-gas chromatographic systems to optimize the energy consumption as well as the instrumentation dimensions. A number of applications in the essential oil field is also included.

Preliminary prospection of phytotherapic compounds from the essential oils from barks and leaves of Umburana (Commiphora Leptophloeos)

Abstract The potential of the biome caatinga (exclusive from northeastern Brazil) has been evaluated in recent research for application in the pharmaceutical industry. Among the species of medicinal plants from caatinga, one can highlight the Commiphora leptophloeos (umburana), which has been used as infusions and syrups by the regional population for inflammatory and infectious diseases. Essential oils from umburana leaves and barks were obtained in a Clevenger apparatus and analyzed by gas chromatography/mass spectrometry, and total phenolic and flavonoids were determined by spectrophotometric analysis. It was observed that a large part of the major compounds present in the essential oil is described as having antitumor activity, enabling research in investigational oncology with umburana (C. leptophloeos). In addition, some little explored components have been identified, such as cadinene, alpha-selinene, and elemenone. Despite being easily found in several plants, there are no clinical trials involving their biological activity in a well-defined isolated form, which could make exploring new studies possible. Furthermore, the presence of phenolic compounds and flavonoids allows future studies about the potential antimicrobial and antioxidant activity.

Effects of Biostimulants on the Chemical Composition of Essential Oil and Hydrosol of Lavandin (Lavandula x intermedia Emeric ex Loisel.) Cultivated in Tuscan-Emilian Apennines.

In recent years, it has been shown that biostimulants can efficiently enhance plant metabolic processes, leading to an increased production of essential oil (EO) in aromatic plants. The present study aimed to evaluate the effects of two different commercial biostimulants composed of amino acids and seaweed extract, normally used for food organic crops, on the production and composition of EO and hydrosol of Lavandula x intermedia, cultivar "Grosso". The products were applied during 2020 growing season on lavender crops in three different locations of the Northern Italian (Emilia-Romagna Region) Apennines. Plants were harvested and EOs extracted by steam distillation and analyzed by gas chromatography. Both biostimulants affected the yield of EO per plant (+11% to +49% depending on the treatment/farm combination) without significantly changing the chemical composition of EOs and hydrosols. Conversely, the composition of EOs and hydrosols are related to the location, and the main compounds of "Grosso" cultivar, limonene, 1,8-cineole, cis-ocimene, linalool, camphor, borneol, terpinen-4-ol, and linalyl acetate, show different ratios at the experimental test sites. The differences might be due to the sunlight exposure and various maintenance of the crops over the years. In conclusion, these results suggest that the employment of biostimulants on lavandin crops do not endanger the quality of the EO while increasing biomass production and promoting the sustainability of the crop.

Comparison of dimension reduction methods on fatty acids food source study.

Serum fatty acids (FAs) exist in the four lipid fractions of triglycerides (TGs), phospholipids (PLs), cholesteryl esters (CEs) and free fatty acids (FFAs). Total fatty acids (TFAs) indicate the sum of FAs in them. In this study, four statistical analysis methods, which are independent component analysis (ICA), factor analysis, common principal component analysis (CPCA) and principal component analysis (PCA), were conducted to uncover food sources of FAs among the four lipid fractions (CE, FFA, and TG + PL). Among the methods, ICA provided the most suggestive results. To distinguish the animal fat intake from endogenous fatty acids, FFA variables in ICA and factor analysis were studied. ICA provided more distinct suggestions of FA food sources (endogenous, plant oil intake, animal fat intake, and fish oil intake) than factor analysis. Moreover, ICA was discovered as a new approach to distinguish animal FAs from endogenous FAs, which will have an impact on epidemiological studies. In addition, the correlation coefficients between a published dataset of food FA compositions and the loading values obtained in the present ICA study suggested specific foods as serum FA sources. In conclusion, we found that ICA is a useful tool to uncover food sources of serum FAs.

New Insights on Volatile Components of Vanilla planifolia Cultivated in Taiwan.

Vanilla (Vanilla planifolia) is a precious natural flavoring that is commonly used throughout the world. In the past, all vanilla used in Taiwan was imported; however, recent breakthroughs in cultivation and processing technology have allowed Taiwan to produce its own supply of vanilla. In this study, headspace solid-phase microextraction (HS-SPME) combined with GC-FID and GC-MS was used to analyze the volatile components of vanilla from different origins produced in Taiwan under different cultivation and processing conditions. The results of our study revealed that when comparing different harvest maturities, the composition diversity and total volatile content were both higher when the pods were matured for more than 38 weeks. When comparing different killing conditions, we observed that the highest vanillin percentage was present after vanilla pods were killed three times in 65 °C treatments for 1 min each. From the experiment examining the addition of different strains, the PCA results revealed that the volatiles of vanilla that was processed with Dekkera bruxellensis and Bacillus subtilis was clearly distinguished from which obtained by processing with the other strains. Vanilla processed with B. subtilis contained 2-ethyl-1-hexanol, and this was not detected in other vanillas. Finally, when comparing the vanillin percentage from seven different regions in Taiwan, vanilla percentage from Taitung and Taoyuan Longtan were the highest.

Actividad antibacteriana de un gel experimental de Eucalyptus globulus Labill frente a Porphyromonas gingivalis / Antibacterial activity of an experimental Eucalyptus globulus Labill gel against Porphyromonas gingivalis

Introducción: Las plantas medicinales han demostrado poseer propiedades antibacterianas para el control de la periodontitis. Objetivo: Determinar la actividad antibacteriana frente a Porphyromonas gingivalis ATCC 33277 de un gel experimental compuesto por aceite esencial de Eucalyptus globulus Labill. Métodos: Se realizó un estudio experimental in vitro. Se empleó el programa EPi InfoTM para el cálculo de las repeticiones. El aceite esencial se obtuvo por el método de arrastre de vapor; se identificó su composición química por cromatografía de gases acoplada a espectrometría de masas. Se evaluó la concentración mínima inhibitoria (CMI) y concentración mínima bactericida (CMB). Se realizó un ensayo de difusión en Agar para medir los halos de inhibición del gel experimental al 4,46 por ciento frente a P. gingivalis, la comparación con clorhexidina al 0,12 por ciento se evaluó con la prueba U de Mann-Whitney. Se adoptó un nivel de significancia del 5 por ciento . Resultados: Se identificaron 11 constituyentes en el aceite esencial, los principales componentes químicos fueron 3-heptadecene, (Z)- (36,13 por ciento ), 1-tridecene (14,7 por ciento ) y 1,8-cineole (9,72 por ciento ). La CMI del aceite esencial fue 36,195 mg/mL y la CMB fue 39,114 mg/mL. Los halos de inhibición del gel experimental de P. gingivalis fueron 25,533 mm ± 0,960. mm. Se observaron diferencias estadísticamente significativas frente a clorhexidina al 0,12 por ciento (23,282 ± 0,345) (p < 0,05). Conclusiones: El gel experimental al 4,46 por ciento compuesto por aceite esencial de Eucalyptus globulus Labill presentó una actividad antibacteriana importante frente a Porphyromonas gingivalis ATCC 33277(AU)

Introduction: Medicinal plants have proved to have antibacterial properties for the control of periodontitis. Objective: Determine the antibacterial activity against Porphyromonas gingivalis ATCC 33277 of an experimental gel composed of essential Eucalyptus globulus Labill oil. Methods: An in vitro experimental study was conducted. The software EPi InfoTM was used to estimate the repetitions. The essential oil was obtained by steam entrainment, and its chemical composition was determined by gas chromatography / mass spectrometry. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were also evaluated. An agar diffusion test was performed to measure the inhibition haloes of the 4.46 percent experimental gel against P. gingivalis. Comparison with 0.12 percent chlorhexidine was evaluated with the Mann-Whitney U test. A 5 percent significance level was adopted. Results: A total 11 constituents were identified in the essential oil. The main chemical components were 3-Heptadecene, (Z)- (36.13 percent), 1-Tridecene (14.7 percentand 1,8-cineole (9.72 percent). MIC of the essential oil was 36.195 mg/ml, whereas MBC was 39.114 mg/ml. The inhibition haloes of the experimental P. gingivalis gel were 25.533 mm ± 0.960 mm. Statistically significant differences were observed versus 0.12 percent chlorhexidine (23.282 ± 0.345) (p < 0.05). Conclusions: The 4.46 percent experimental gel composed of Eucalyptus globulus Labill essential oil displayed considerable antibacterial activity against Porphyromonas gingivalis ATCC 33277(AU)

Separation performance of the copolymer and homopolymer of aliphatic polycarbonate diols as the stationary phases for capillary gas chromatography.

This work presents the investigation of two aliphatic polycarbonate diols (CAPC and HAPC) as the stationary phases for capillary gas chromatography (GC). The CAPC and HAPC capillary columns showed moderate polarity and high column efficiency of 3704 - 4545 plates/m measured by n-octanol and naphthalene at 120 °C. It was found that despite their similar chemical compositions, CAPC and HAPC differ largely in their selectivity towards the isomers of alkanes, methylpyridines and xylenes. As demonstrated, the CAPC column exhibits advantageous comprehensive performance over the HAPC column and the commercial PEG column. Particularly, the CAPC column exhibits higher resolving performance towards the isomers indicated above and the Grob mixture than the HAPC column. Also, it shows distinct advantages over the PEG column in separating the Grob mixture, the isomers of diethylbenzenes and cymenes, and practical analysis of chemical products and the essential oil from the leaves of Rhododendron dauricum L. Additionally, the CAPC column has excellent repeatability and reproducibility on analyte retention times with the relative standard deviation (RSD) values in the range of 0.05% - 0.08% for run-to-run, 0.12% - 0.19% for day-to-day and 2.6% - 4.9% for column-to-column, respectively. Its applications to purity test of chemical products and GC-MS analysis of the essential oil demonstrate its promising future for practical GC analyses.

Preparation and characterization of selenium-rich polysaccharide from Phellinus igniarius and its effects on wound healing.

The modified of polysaccharides show various bio-activities. In our work, Phellinus igniarius Selenium-enriched mycelias polysaccharides (PSeP) were prepared from Phellinus igniarius, and its antioxidant and anti-inflammatory effects on injured mice were evaluated. The selenium content and physical properties of polysaccharides were characterized by GC, HPGPC, and FT-IR analysis. The results showed that PSeP could reduce reactive oxygen species (ROS) levels, myeloperoxidase (MPO) activity as well as malondialdehyde (MDA) content. Meanwhile, it increased the enzyme activities of glutathione peroxidase (GSH-Px) and catalase (CAT). Finally, it showed obvious wound healing effects in vivo. Moreover, PSeP could clear the ROS without obvious cytotoxicity. PSeP could further improve its ability to clear ROS level to promote skin wound healing in mice three days in advance.

Measuring Conjugated Linoleic Acid (CLA) Production by Bifidobacteria.

The biological significance of conjugated fatty acids (CFAs) has been linked to positive health effects based on biomedical, in vitro, and clinical studies. Of note, conjugated linoleic acids (CLAs) are the most widely characterized fatty acids as geometric isomers cis-9,trans-11 and trans-10,cis-12 CLA occur naturally in ruminant fats, dairy products, and hydrogenated oils. Concerning CLAs, it is known that bacterial biohydrogenation, a process whereby ruminal bacteria or starter cultures of lactic acid bacteria have the ability to synthesize CLA by altering the chemical structure of essential fatty acids via enzymatic mechanisms, produces a multitude of isomers with desirable properties. Bifidobacterium species are classed as food grade microorganisms and some of these strains harness molecular determinants that are responsible for the bioconversion of free fatty acids to CLAs. However, molecular mechanisms have yet to be fully elucidated. Reports pertaining to CLAs have been attributed to suppressing tumor growth, delaying the onset of diabetes mellitus and reducing body fat in obese individuals. Given the increased attention for their bioactive properties, we describe in this chapter the qualitative and quantitative methods used to identify and quantify CLA isomers produced by bifidobacterial strains in supplemented broth media. These approaches enable rapid detection of potential CLA producing strains and accurate measurement of fatty acids in biological matrices.

Baseline red blood cell and breast milk DHA levels affect responses to standard dose of DHA in lactating women on a controlled feeding diet.

BACKGROUND: The importance of providing the newborn infant with docosahexaenoic acid (DHA) from breast milk is well established. However, women in the United States, on average, have breast milk DHA levels of 0.20%, which is below the worldwide average (and proposed target) of >0.32%. Additionally, the relationship between maternal red blood cell (RBC) and breast milk DHA levels may provide insight into the sufficiency of DHA recommendations during lactation. Whether the standard recommendation of at least 200 mg/day of supplemental DHA during lactation is sufficient for most women to achieve a desirable RBC and breast milk DHA status is unknown. METHODS: Lactating women (n = 27) at about 5 weeks postpartum were enrolled in a 10-12 week controlled feeding study that included randomization to 480 or 930 mg choline/d (diet plus supplementation). As part of the intervention, all participants were required to consume a 200 mg/d of microalgal DHA. RBC and breast milk DHA levels were measured by capillary gas chromatography in an exploratory analysis. RESULTS: Median RBC DHA was 5.0% (95% CI: 4.3, 5.5) at baseline and 5.1% (4.6, 5.4) after 10 weeks of supplementation (P = 0.6). DHA as a percent of breast milk fatty acids increased from 0.19% (0.18, 0.33) to 0.34% (0.27, 0.38) after supplementation (P<0.05). The proportion of women meeting the target RBC DHA level of >5% was unchanged (52% at baseline and week 10). The proportion of women achieving a breast milk DHA level of >0.32% approximately doubled from 30% to 56% (p = 0.06). Baseline RBC and breast milk DHA levels affected their responses to supplementation. Those with baseline RBC and breast milk DHA levels above the median (5% and 0.19%, respectively) experienced no change or a slight decrease in levels, while those below the median had a significant increase. Choline supplementation did not significantly influence final RBC or breast milk DHA levels. CONCLUSIONS: On average, the standard prenatal DHA dose of 200 mg/d did not increase RBC DHA but did increase breastmilk DHA over 10 weeks in a cohort of lactating women in a controlled-feeding study. Baseline DHA levels in RBC and breast milk affected the response to DHA supplementation, with lower levels being associated with a greater increase and higher levels with no change or a slight decrease. Additional larger, dose-response DHA trials accounting for usual intakes and baseline DHA status are needed to determine how to best achieve target breast milk DHA levels and to identify additional modifiers of the variable breast milk DHA response to maternal DHA supplementation.