Profile of selenium in soil and crops in seleniferous area of Punjab,India by neutron activation analysis

In the Nawanshahr–Hoshiarpur region of Punjab, India, more than 1000 hectares of agricultural land is significantly affected by high levels of selenium (Se). Studies were carried out to examine Se levels in soil and crops such as wheat grains, wheat husk, rice, maize and mustard using neutron activation analysis. The Se concentrations in soil and crop products were found to be ranging from 2.7 to 6.5 mg kg⁻¹ and 13 to 670 mg kg⁻¹, respectively, indicating significantly high selenium in these crop products. Two reference materials were analysed for Se contents by INAA as controls.     

Selenium supplementation of Portuguese wheat cultivars through foliar treatment in actual field conditions

Selenium (Se) is a trace element essential to the well-being and health quality of humankind. Plant-derived foodstuffs, namely cereals, are the major dietary sources of Se in most countries throughout the world, even if Se contents are strongly dependent upon the corresponding levels in cereal-growing soils. Therefore, wheat is one of the staple crops that appears as an obvious candidate for Se biofortification, considering its gross-tonnage production and nutritional relevance worldwide. The present paper focuses on the ability of bread and durum wheat—Triticum aestivum L. and Triticum durum Desf., respectively—to accumulate Se after supplementation via a foliar-addition procedure. Two of the most representative wheat cultivars in Portugal—Jordão (bread) and Marialva (durum)—have been selected for supplementation trials, following the same agronomic practices and field schedules as the regular (non-supplemented) crops of those varieties (sowing: November 2010; harvesting: July 2011). Foliar additions were performed at the booting and grain-filling stages, using sodium selenate and sodium selenite solutions at three different Se concentrations—equivalent to field supplementation rates of 4, 20 and 100 g of Se per ha—with and without potassium iodide. Selenium contents in wheat grains obtained under foliar application are compared to data from regular wheat samples (field blanks) grown at the same soil/season, yet devoid of any Se supplementation. Total Se in all field samples was determined by cyclic neutron activation analysis (CNAA), via the short-lived nuclide ^77mSe (half-life time: 17.5 s), in the Portuguese Research Reactor (RPI; CTN-IST, Sacavém). Quality control of the analytical procedure was asserted through concurrent analyses of NIST-SRM^® 1567a (Wheat Flour). Results show that foliar additions can increase Se contents in mature grains up to 15 and 40 times for Marialva and Jordão, respectively, when compared to non-supplemented crops. Jordão and Marialva varieties responded differently to the stage of application.     

Simultaneous speciation of arsenic (As(III), MMA, DMA, and As(V)) and selenium (Se(IV), Se(VI), and SeCN−) in petroleum refinery aqueous streams

High-performance liquid chromatography (HPLC) coupled to an ICP-MS with an octapole reaction system (ORS) has been used to carry out quantitative speciation of selenium (Se) and arsenic (As) in the stream waters of a refining process. The argon dimers interfering with the ⁷⁸Se and ⁸⁰Se isotopes were suppressed by pressurizing the octapole chamber with 3.1 mL min⁻¹ H₂ and 0.5 mL min⁻¹ He. Four arsenic species arsenite—As(III), arsenate (As(V)), monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA)—and three inorganic Se species—selenite Se(IV), selenate Se(VI), and selenocyanate (SeCN⁻)—were separated in a single run by ion chromatography (IC) using gradient elution with 100 mmol L⁻¹ NH₄NO₃, pH 8.5, adjusted by addition of NH₃, as eluent. Repeatabilities of peak position and of peak area evaluation were better than 1% and about 3%, respectively. Detection limits (as 3σ of the baseline noise) were 81, 56, and 75 ng L⁻¹ for Se(IV), Se(VI), and SeCN⁻, respectively, and 22, 19, 25, and 16 ng L⁻¹ for As(III), As(V), MMA, and DMA, respectively. Calibration curve R ² values ranged between 0.996 and 0.999 for the arsenic and selenium species. Column recovery for ion chromatography was calculated to be 97 ± 6% for combined arsenic species and 98 ± 3% for combined selenium species. Because certified reference materials for As and Se speciation studies are still not commercially available, in order to check accuracy and precision the method was applied to certified reference materials, BCR 714, BCR 1714, and BCR 715 and to two different refinery samples—inlet and outlet wastewater. The method was successfully used to study the quantitative speciation of selenium and arsenic in petroleum refinery wastewaters.     

Study of the bioavailability of selenium in cows’ milk after a supplementation of cow feed with different forms of selenium

The purpose of the work described in this paper was to develop an easy and quick in-vitro method for comparing the bioavailability of selenium in cows’ milk after different cow feed. The study focuses on bioavailability differences resulting from the use of different selenium species (organic selenium as selenised yeast and sodium selenite) for supplementation of forage. A procedure for determination of selenium in cows’ milk and dialysates, by hydride-generation atomic-fluorescence spectrometry (HG-AFS) after microwave-assisted acid digestion, was optimised. The results show it is possible to obtain cows’ milk enriched with selenium at different concentration without altering the original composition of the milk. The bioavailability was statistically greater for cows’ milk obtained after supplementation of forage with organic selenium at levels of 0.4 and 0.5 μg Se g⁻¹ than for that obtained after supplementation with inorganic and organic selenium at levels of 0.2 and 0.3 μg Se g⁻¹.     

Separation and determination of selenium in water samples by the combination of APDC coprecipitation: X-ray fluorescence spectrometry

A sensitive and non chromatographic analytical procedure for the separation of inorganic selenium species in natural water has been performed. A combination of APDC coprecipitation and determination by an absolute thin layer Energy dispersive X-ray fluorescence spectrometry method was used. The influence of various analytical parameters such as element concentration, oxidation states and pH on the recoveries of Se (IV) was examined. The presence of organic matter and bicarbonate anions, typical components in Cuban groundwater samples, was also tested. Negligible matrix effects were observed. At pH 4 a 100% recovery was found for Se (IV). The coprecipitation recovery of the oxidized selenium species (Se (VI)) was null for the selected concentration range (5–100 μg L⁻¹). When the Se (VI) was reduced by heating the solution with 4 mol L⁻¹ HCl, quantitative recovery was also obtained. The determination of total selenium was conducted by the application of the oxidation–reduction process and the analytical procedure for Se (IV). Se (VI) content was calculated as the difference between total selenium and Se (IV). The detection limit was 0.13 μg L⁻¹. The relative standard deviation was lower than 3.5% for 5 μg L⁻¹ of Se (IV). The trueness of the method was verified by using standardized hydride generation-atomic absorption spectrometry technique. The results obtained using the EDXRF technique were in good agreement with the ones determined by HG-AAS. The proposed method was applied to the determination of Se (IV) in surface water and groundwater samples.     

Radiotracing selenium in bread-wheat seeds for a Se-biofortification program: an optimization study in seed enrichment

Selenium (Se) is an essential micronutrient for human health, but its deficiency may affect at least one billion people worldwide. Plants and plant-derived products transfer the soil-uptaken Se to humans through the food chain, which is hardly enough when soils have been always poor or already exhausted in bioavailable Se species. Other than agronomic approaches for enhancing Se levels in cereals, such as soil and foliar supplements, seed enrichment may be viewed as an alternative Se-biofortification technique. This study addresses the protocol for preparing Se-enriched wheat seeds, with the specific purpose of optimizing the administration of Se to the seeds prior to sowing. The first step was to soak an amount of bread-wheat seeds in an active Se solution, made with irradiated [Na₂O₄Se], and then monitoring ⁷⁵Se in periodically-retrieved samples from that original amount. To avoid losing Se to soil (after sowing), and, especially, to ensure that Se gets really absorbed into the seeds—and not just adsorbed onto them—the washing time of the seeds should be optimized as well. This was carried out by washing Se-treated seeds several times, until no significant amount of the radiotracer could be detected in the washing water. In what concerns the full optimization procedure, the overall results of the present study point to an optimum time of 48 h for soaking and 24 h for washing.     

Selenium speciation in cow milk obtained after supplementation with different selenium forms to the cow feed using liquid chromatography coupled with hydride generation-atomic fluorescence spectrometry

The purpose of this paper is to develop an easy and quick on-line selenium speciation method (LC-UV-HG-AFS) in cow milk obtained after different supplementation to cow feed. This study focuses on selenium speciation in cow milk after the use of different selenium species (organic selenium as selenised yeast and inorganic selenium as sodium selenite) in the supplementation of forages. Separation was carried out on a μBondapack C₁₈ column with the positively charged ion-pairing agent tetraethylammonium chloride in the mobile phase. The optimization of pre-reduction conditions was carried out; this step was done with UV irradiation and a heating block to improve the reduction of the different Se-compounds. Variables such as exposure time, hydrochloric acid concentration and temperature were studied. The detection limits for SeCyst₂, Se(IV), SeMet and Se(VI) were 0.4, 0.5, 0.9 and 1.0 μg l⁻¹, respectively. The proposed method was applied to cow milk samples. The milk samples obtained after an organic supplementation of feeding as selenised yeast present three species of selenium, SeCyst2, Se(IV) and SeMet, while only SeCyst2 and Se(IV) are present in milk samples obtained after an inorganic supplementation of feeding.     

GC–ICP–MS determination of dimethylselenide in human breath after ingestion of <Superscript>77</Superscript>Se-enriched selenite: monitoring of in-vivo methylation of selenium

The amount of volatile dimethylselenide (DMSe) in breath has been monitored after ingestion of sub-toxic amounts of selenium (300 μg ⁷⁷Se, as selenite) by a healthy male volunteer. The breath samples were collected in Tedlar bags every hour in the first 12 h and then at longer intervals for the next 10 days. The samples were subjected to speciation analysis for volatile selenium compounds by use of cryotrapping–cryofocussing–GC–ICP–MS. Simultaneously, all urine was collected and subjected to total selenium determination by use of ICP–MS. By monitoring m/z 82 and 77, background or dietary selenium and selenium from the administered selenite were simultaneously determined in the urine and in the breath—dietary selenium only was measured by monitoring m/z 82 whereas the amount of spiked ⁷⁷Se (99.1% [enriched spike]) and naturally occurring selenium (7.6% [natural abundance]) were measured by monitoring m/z 77. Quantification of DMSe was performed by using DMSe gas samples prepared in Tedlar bags (linear range 10–300 pg, R ²=0.996, detection limit of Se as DMSe was 10 pg Se, or 0.02 ng L⁻¹, when 0.5 L gas was collected). Dimethylselenide was the only selenium species detected in breath samples before and after the ingestion of ⁷⁷Se-enriched selenite. Additional DM⁷⁷Se was identified as early as 15 min after ingestion of the isotopically-labelled selenite. Although the maximum concentration of ⁷⁷Se in DMSe was recorded 90 min after ingestion, the natural isotope ratio for selenium in DMSe (77/82) was not reached after 20 days. The concentration of DMSe correlated with the total Se concentration in the urine during the experiment (R ²=0.80). Furthermore, the sub-toxic dose of 300 μg selenium led to a significant increase of DMSe and renal excretion of background selenium, confirming that selenium ingested as selenite is homeostatically controlled by excretion. The maximum concentration of DMSe resulting from the spiked selenite was 1.4 ng Se L⁻¹ whereas the dietary background level was less than 0.4 ng Se L⁻¹. Overall excretion as DMSe was calculated to be 11.2% from the ingested selenite within the first 10 days whereas urinary excretion accounts for nearly 18.5%.     

Updated estimates of the selenomethionine content of NIST wheat reference materials by GC–IDMS

Updated estimates of the selenomethionine content of four NIST wheat reference materials have been obtained by use of a revised gas chromatography–stable-isotope dilution mass spectrometric method. The revised method makes use of digestion with methanesulfonic acid, which enables more complete recovery of endogenous selenomethionine than was previously achieved by overnight denaturing treatment in 0.1 mol L⁻¹ HCl. The NIST wheat reference materials each contain approximately 55% of their total Se content as selenomethionine. Information about forms of Se in reference materials adds value to these materials in Se speciation studies. Estimates of selenomethionine content are also provided for other wheat samples, including several grown under conditions of exposure to high Se levels. These samples also contain approximately 55% of their total Se content as selenomethionine. The consistent level of 55% of total selenium occurring in the form of selenomethionine when the total selenium content varies by a factor of 500 is suggestive of an active mechanism of incorporation of selenium into wheat grain. Figure Selenomethionine content of wheat samples     

Investigation of the appearance of supplemental enriched Se-76 using the human nail as a dietary monitor

The principal objective of this study was to determine if the use of a stable enriched tracer of Se-76 could be used to determine the delay time between a dietary intake of selenium and its appearance in fingernails and toenails. Selenium is an essential trace element in human nutrition. It has been studied at the Missouri University Research Reactor (MURR) for the past 15 years using an Instrumental Neutron Activation Analysis (INAA) technique. The principal route of human exposure to selenium is through the diet. Selenium concentrations of nails, blood, hair, and urine have been used as indicators of dietary selenium intake. In this study, a cohort consisting of seven men and five women ingested three selenium supplements of 150 g each over a three day period. The selenium was enriched in Se-76 (96.48%) and ingested as selenite in orange juice following an overnight fast. Fingernails and toenails were collected prior to the selenium supplementation and for several months afterward to be used as biochemical indicators. The peak⁷⁶Se concentration in the fingernails and toenails occurred at 19–23 and 16–32 weeks after supplementation, respectively.     

Concentration factors for 226Ra in the mullet (Mugilidae) species Mugil cephalus from the South Adriatic Sea

²²⁶Ra activity concentration in the mullet (Mugilidae) species Mugil cephalus whole individuals, and some organs (gills, gastrointestinal system, fins, muscle and bones), was measured by the γ-coincidence spectrometer PRIPYAT-2M. ²²⁶Ra transfer parameters [concentration factors (CFs)] from seawater, sediment and mud with detritus to fish tissues, and annual intake by humans consuming this fish species, have been estimated. Minimum detected radium activity concentration in whole M. cephalus individuals was found to be 0.89 ± 0.42 to 3.09 ± 0.41 Bq kg⁻¹, with arithmetic mean of 1.65 ± 0.39 Bq kg⁻¹. An average concentration in muscles is found to be 2.28 ± 0.84 Bq kg⁻¹, in gills—5.02 ± 1.85 Bq kg⁻¹, in gastrointestinal system—12.88 ± 1.71 Bq kg⁻¹, and in bones—14.72 ± 3.75 Bq kg⁻¹. No one fins showed radium activity above minimum detectable one. Annual intake of ²²⁶Ra by human consumers of this fish species is estimated to provide an effective dose of 0.006 mSv year⁻¹. CFs for ²²⁶Ra indicating transfer from seawater to whole individuals ranged from 8.9 to 30.9, and those indicating transfer from the sediment and mud with detritus—from 0.11 to 0.39 and from 0.08 to 0.3, respectively. The seawater to bones CFs varied from 97.9 to 197.3, to gastrointestinal system—from 59 to 178.8, to gills—from 22.5 to 68.3, to muscles—from 17 to 30.8.     

Study of the influence of carboxymethylcellulose on the absorption of selenium (and selected metals) in a target plant

The aim of the present paper is the study of the influence of a polysaccharide (carboxymethylcellulose, CMC) on uptake by a target plant Lactuca sativa (LS) of selenium and some metals. LS was grown on a well characterized soil: such as, treated with 1.5 mg kg⁻¹ Se(IV) only and with two levels of CMC (3 and 30 mg kg⁻¹). Similar experiments were carried out by using Se(VI) instead of Se(IV). Uptake was evaluated through the quantification of total content of Se in dried leaves and roots by a suitable technique (graphite furnace atomic absorption spectrophotometry, instrumental neutron activation analysis and differential pulse cathodic stripping voltammetry). Results evidenced as the uptake of selenium was dependent on the form of selenium added to the soil: Se(VI) is accumulated much more then Se(IV) according to its lower toxicity and higher mobility. The simultaneous presence of CMC led to a lower selenium uptake in leaves, whereas no clear influence was evidenced in roots. Furthermore, the presence of CMC influenced also the mobility process (soil→plant) of several other metals: a lower content of them was detected in plants when CMC was present in the soil.     

Selenium and mercury determination in biological samples using gamma–gamma coincidence and Compton suppression

Biological materials containing trace amounts of mercury and selenium were examined using neutron activation analysis. They were analyzed using Compton suppression and γ–γ coincidence counting. The 279 keV photopeak of activated mercury (²⁰³Hg) was analyzed in order to observe the mercury content in these samples. Selenium, an element found in many biological samples, interferes with the analysis of ²⁰³Hg when activated (⁷⁵Se). Because the selenium interference comes from a cascading emission, Compton suppression was utilized to reduce this interference. In order to fully characterize the selenium content in the samples, γ–γ coincidence was used which reduced the background and eliminated bremsstrahlung interference produced from neutron activated phosphorous through the ³¹P(n, γ)³²P reaction which is a pure beta emitter. As a result, we determined the mercury and selenium concentrations in three standard reference materials, which contain varying ratios of mercury to selenium concentrations. This study also showed that these types of concentrations can be determined from small (<500 mg) sample masses. Further work needs to be done on wet samples that require dehydration, as mercury can be lost through this process.     

Use of granulated modified zeolite Y for the removal of inorganic arsenic and selenium species

Column studies were performed to evaluate the performance of modified zeolite-Y with ion Fe (zeolite-FeY) in removing As(III), As(V), Se(IV) and Se(VI) from groundwater. The removal capacities for zeolite-FeY was carried out on arsenic and selenium species in aqueous solution by co-precipitation technique with DBDTC-Pp complex in the pH range of 1.5–2.5 followed by the neutron activation analysis (NAA) using a TRIGA-MkII reactor with an average flux of 2.1 × 10¹² neutrons cm⁻² s⁻¹ and inductively coupled plasma-mass spectrometry (ICP-MS) technique as comparison. The accuracy between the results obtained from both techniques were compared and evaluated.     

Speciation analysis of selenium enriched green onions (Allium fistulosum) by HPLC-ICP-MS

Green onions (Allium fistulosum) enriched with 10 or 100 μg mL^− 1 Se(IV) or SeMet were analyzed for total selenium and species distribution. Anion and cation exchange chromatographies were applied for the separation of selenium species with mass spectrometric detection. Two different sample preparation methods (NaOH and enzymatic) were compared from the Se extraction efficiency point of view. Total selenium concentration accumulated by the onions reached the 200 μg g^− 1 level expressed for dry weight when applying SeMet at a concentration of 100 μg mL^− 1 as the source of Se. Speciation studies revealed that both in onion bulbs and leaves the predominant form of organic selenium is Se-methyl-selenocysteine (MeSeCys). When Se(IV) was applied for Se-enrichment at a concentration level of 100 μg mL^− 1 both onion leaf and bulb contained a significant amount of inorganic selenium. An unknown compound was also detected.     

Determination of selenium status using the nail biologic monitor in a canine model

Toenails and fingernails are routinely used to estimate selenium status in epidemiological studies; however, literature validating nail selenium concentration as a surrogate for critical organs is limited. In this study diets of intact male dogs were selenium supplemented at two physiological levels (3 and 6 μg/kg/day) in two different forms, selenomethionine and selenium-enriched bioformed yeast. The selenium-adequate basal diet consumed by the treatment and control groups during the 4-week run-in period and throughout the trial contained 0.3 ppm selenium. After 7 months the dogs in the two treatment groups and the control group were euthanized. Representative tissue samples from prostate, brain, liver, heart and skeletal muscle were collected, rinsed and frozen. Toenail clippings from multiple toes were also collected. Selenium was determined by neutron activation analysis using Se77m (half life = 17.4 s) at the University of Missouri Research Reactor Center. NIST SRM 1577, Bovine Liver was analyzed as a quality control. The analysts were blinded to control and treatment group assignments. As expected, tissue selenium levels increased proportionally with supplementation. A slightly greater increase in tissue selenium was observed for the purified selenomethionine compared to the bioformed yeast; however this trend was significant only for brain tissue. Toenail selenium concentrations and tissue selenium were highly correlated (p < 0.003) with Pearson coefficients of 0.759 (skeletal muscle), 0.745 (heart), 0.729 (brain), 0.723 (prostate), and 0.632 (liver). The toenail biologic monitor accurately assesses selenium status in skeletal muscle, heart, brain, prostate, and liver in the canine model.     

Retention study of inorganic and organic selenium compounds on a silica-based reversed phase column with mixed ion-pairing reagents

Summary Separation of seven inorganic and organic selenium compounds, namely selenic acid [Se(VI)], selenous acid [Se(IV)], trimethylselenonium iodide (TMSe⁺), selenocystine (SeCys), selenomethionine (SeMet), selenoethionine (Seet), and selenocystamine (SeCM), has been performed on a LiChrosorb C 18 column by using mixed ion-pair reagents; 1-butanesulfonic acid and tetramethylammonium hydroxide. Flame atomic absorption spectrometry (FAAS) was used as an element-specific detector. The retention behaviors of selenium compounds in terms of several chromatographic parameters, such as pH of the mobile phase, the concentrations of ion-pair reagents, and the content of organic modifier (methanol) were investigated. It was found that the separation of both inorganic and organic selenium compounds can be achieved within 12 min with a mobile phase of 10 mM 1-butanesulfonic acid −4 mM tetramethylammonium hydroxide −4 mM malonic acid −0.05% methanol adjusted to pH 4.5 at a flow rate of 1.0 mL min⁻¹. The results obtained in this study showed that the use of mixed ion-pair reagents is very useful to improve the separation of selenium compounds. The applicability of this technique for the speciation of selenium compounds in real samples was demonstrated by the determination of selenium compounds in a selenium nutritional supplement. The results were found to be in good agreement with those obtained by ion-exchange HPLC-ICP-MS.     

Folate analysis in foods by UPLC-MS/MS: development and validation of a novel, high throughput quantitative assay; folate levels determined in Australian fortified breads

An ultra-performance liquid chromatography-tandem mass spectrometry method was developed, optimised and validated for the quantification of synthetic folic acid (FA), also called pteroyl-l-glutamic acid or vitamin B9 and naturally occurring 5-methyltetrahydrofolate (5-MTHF) found in folate-fortified breads. Optimised sample preparation prior to analysis involved addition of ¹³C₅ labelled internal standards, treatments with α-amylase and rat serum, solid-phase extraction using aromatic-selective cartridges and ultra-filtration. Analytes were separated on a Waters ACQUITY HSS T3 column during a 6-min run and analysed by positive ion electrospray selected reaction monitoring MS/MS. Standard calibration curves for the two analytes were linear over the range of 0.018–14 μg FA/g of fresh bread (r ² = 0.997) and 9.3–900 ng 5-MTHF/g of fresh bread (r ² = 0.999). The absolute recoveries were 90% and 76% for FA and 5-MTHF, respectively. Intra-day coefficients of variation were 3% for FA and 18% for 5-MTHF. The limit of detection was 9.0 ng/g for FA and 4.3 ng/g for 5-MTHF, determined using pre-extracted tapioca starch as the blank matrix. The assay is rugged, fast, accurate and sensitive, applicable to a variety of food matrices and is capable of the detection and quantification of the naturally occurring low levels of 5-MTHF in wheat breads. The findings of this study revealed that the FA range in Australian fortified breads was 79–110 μg/100 g of fresh bread and suggest that the flour may not have the mandated FA fortification level (200–300 μg/100 g of flour), though this cannot be determined conclusively from experimental bread data alone, as variable baking losses have been documented by other authors.     

Variability in the distribution of selenium in healthy heart tissue measured by neutron activation analysis

Chronic dietary deficiency of selenium has been shown to be associated with degenerative heart disease in production animals in the U.S. and in the human in parts of China. In the latter, subjects in the endemic areas suffer high rates of a cardiomyopathy known as Keshan's Disease which is normally fatal in early adulthood and can be prevented, or reversed in its early stages, via selenium supplementation. Selenium, as the active moiety in the enzyme glutathione peroxidase, protects against oxidative attack of cell membranes by peroxides formed during normal metabolism. In this study, we investigated the distribution of selenium in healthy porcine and bovine heart tissue freshly collected at slaughter. The whole heart was perfused with DI water and carefully de-fatted. Representative samples of left and right atria and ventricles and the interventricular septum were collected, lyophilized and homogenized prior to preparing replicate samples for analysis. Replicates were analyzed for selenium via an INAA scheme employing a 5, 15 and 25 second irradiation (φ_th = 8·10¹³ n·cm⁻²·s⁻¹), decay and real-time count (^77mSe,T _1/2=17.4 s), respectively, using high-resolution gamma-ray spectroscopy with Westphal pulse pile-up correction. Selenium distribution will be discussed relative to differentiated function and oxygenation of the specific tissues.     

Structural and optical characterization of colloidal Se nanoparticles prepared via the acidic decomposition of sodium selenosulfate

Colloidal selenium nanoparticles (NPs) were synthesized via acidic decomposition of sodium selenosulfate. The effects of synthesis and post-synthesis treatment conditions on the size, structure and size distribution of the Se nanoparticles are discussed. It is shown that the decomposition of sodium selenosulfate with non-oxidative acids (e.g., HCl) in aqueous solutions of polymers (sodium polyphosphate, gelatin, polyvinyl alcohol, polyethyleneglycole) and surfactants (sodium dodecylsulfonate, cetylpyridinium chloride) results in the formation of amorphous 25–200 nm Se nanoparticles converting upon ageing at 90 °C into trigonal 150–250 nm Se nanocrystals. Optical properties (absorption and Raman spectra) of freshly prepared and aged Se nanoparticles both in colloidal solutions and in polymeric (polyvinyl alcohol) films are analyzed.